UA-45667900-1

Tuesday, 6 November 2018

When is an SSRI not an SSRI? Low dose SSRIs as Selective Brain Steroidogenic Stimulants (SBSSs) via Allopregnanolone modifying GABAa receptors and neonatal KCC2 expression


Today’s post might seem to have a very complicated tittle, but to regular readers it is really just another take on what we have seen time and time again.
Today we see how another steroid imbalance in autism – low levels of allopregnenolone in this case – affects the neurotransmitter GABA and indeed the chloride transporter KCC2.

Putting Prozac/Zoloft to a better use?

I did report previously on a trial in adults with autism where pregnenolone was used.


Recall that disturbed hormonal homeostasis is a key feature of autism. What matters is the level of each hormone inside the brain (i.e. centrally), not in your blood. The only way to get a reliable idea of what is going on would be to take a sample of spinal fluid.



Today we look at boosting allopregnenolone not with a steroid hormone, but with a 1/10th dose of Prozac (Fluoxetine) or indeed Zoloft (Sertraline). Prozac is a selective serotonin reuptake inhibitor (SSRI) when given at the usual dose of 20-80mg, but at 2.5mg it does not function as an SSRI.
At regular doses selective serotonin reuptake inhibitors (SSRI) drugs like Prozac are well known to cause problems, as do benzodiazepines like Clonazepam.
Thanks to Professor Catterall we saw in earlier posts how tiny doses of Clonazepam have an effect on one particular sub-unit of GABAA receptors. By fine tuning the response of this receptor we saw how a cognitive improvement can be achieved, in some people. The dose is so low there appear to be no long term side effects. At least one other professor of medicine, I am in contact with, has been treating his son with autism with low dose clonazepam for years.
Many adults and children with autism are prescribed Prozac for anxiety. Even Temple Grandin has said she takes Prozac.
At low, non-serotonergic doses, some drugs like Prozac show a different mode of action, they potently, positively, and allosterically modulate GABA action at GABAA receptors. These drugs achieve this by increasing the amount of the steroid hormone allopregnanolone.
Neurosteroid biosynthesis down‐regulation and changes in GABAA receptor subunit composition are a feature of several neurological conditions, including some autism.
Stimulating allopregnenalone biosynthesis will have multiple effects including on TSPO and endocannabinoid receptors.


Brain principal glutamatergic neurons synthesize 3α-hydroxy-5α-pregnan-20-one (Allo), a neurosteroid that potently, positively, and allosterically modulates GABA action at GABAA receptors. Cerebrospinal fluid (CSF) Allo levels are decreased in patients with posttraumatic stress disorder (PTSD) and major depression. This decrease is corrected by fluoxetine in doses that improve depressive symptoms. Emotional-like behavioral dysfunctions (aggression, fear, and anxiety) associated with a decrease of cortico-limbic Allo content can be induced in mice by social isolation. In socially isolated mice, fluoxetine and analogs stereospecifically normalize the decrease of Allo biosynthesis and improve behavioral dysfunctions by a mechanism independent from 5-HT reuptake inhibition. Thus, fluoxetine and related congeners facilitate GABAA receptor neurotransmission and effectively ameliorate emotional and anxiety disorders and depression by acting as selective brain steroidogenic stimulants (SBSSs).                               
When the results of these in vitro studies are compared to those of our in vivo studies, it becomes evident that in mice the doses of fluoxetine and norfluoxetine that cause a rapid increase in brain Allo levels do not exceed brain concentrations in the low nanomolar range, whereas the fluoxetine concentrations that directly activate 3a-HSD in vitro are in the micromolar range. Moreover, the high potency and stereospecificity of fluoxetine and norfluoxetine in decreasing aggressive behavior and normalizing brain Allo content during social isolation (see Table 1, and Figure 3) support the notion that these compounds facilitate the action of 5a-R type I or 3a-HSD by an unidentified indirect mechanism, which is most probably perturbed by protracted social isolation.

Thus, these drugs, which were originally termed ‘SSRI’ antidepressants, may be beneficial in psychiatric disorders because in doses that are inactive on 5-HT reuptake mechanisms, they increase the bioavailability of neuroactive GABAergic steroids. On the basis of these considerations, we now propose that the term ‘SSRIs’ should be changed to the more appropriate term ‘selective brain steroidogenic stimulants’ (SBSSs), which more accurately defines the pharmacological mechanisms expressed by fluoxetine and its congeners.

Conclusions

The pharmacology of the S stereoisomers of fluoxetine and norfluoxetine appears to be prototypic for molecules that possess specific neurosteroidogenic activity. The doses of S-fluoxetine and S-norfluoxetine required to normalize brain Allo content downregulation, pentobarbital action, aggressiveness, and anxiety in socially isolated mice are between 10-fold to 50-fold lower than those required to induce SSRI activity. However, the precise mechanisms of action by which S-fluoxetine and S-norfluoxetine increase neurosteroids remain to be investigated.

Derivatives of S-fluoxetine and S-norfluoxetine, acting with high potency and specificity on brain neurosteroid expression at doses devoid of significant action on brain 5-HT reuptake mechanisms, may represent a new class of pharmacological tools important for the management of anxiety, related mood disorders, dysphoria, fear, and impulsive aggression.

On the basis of these data, new drugs devoid of SSRI activity but that are potent neurosteroidogenic agents should be developed for the treatment of psychiatric disorders that result from the downregulation of neurosteroid expression, including major depression, and in the prevention of PTSD.

France often gets very negative comments about how it treats people with autism, but in the case studies below it looks like some innovative work is going on in some of their day hospitals, where boys and girls with severe autism are sent to pass their time. 

The system in England has recently been highlighted as being pretty appalling, where over 2,000 people with autism are currently detained in Assessment and Treatment Units (ATUs), privately run secure residential "hospitals", at great cost paid for by the State. Those inside might enter with the approval of their family to stay for 3 weeks for respite care, but end up being detained for 3 years, or even longer. The State assumes their guardianship and the individual and parents are powerless. The individuals are kept in prison-like conditions and not surprisingly get worse not better, the worse they get, the harder it is ever to be released. Hard to believe this is still happening.  If you live in England, best not to hand your child over to the State. Someone has even written a book about escaping from such a unit. This is no better than the old State Hospitals in the US, that finally were closed down in the 1970s, that warehoused mentally disabled people, until their premature death.


Autism Spectrum Disorder (ASD) is defined by the copresence of two core symptoms: alteration in social communication and repetitive behaviors and/or restricted interests. In ASD children and adults, irritability, self-injurious behavior (SIB), and Attention Deficit and Hyperactivity Disorders- (ADHD-) like symptoms are regularly observed. In these situations, pharmacological treatments are sometimes used. Selective Serotonin Reuptake Inhibitors- (SSRI-) based treatments have been the subject of several publications: case reports and controlled studies, both of which demonstrate efficacy on the symptoms mentioned above, even if no consensus has been reached concerning their usage. In this article four clinical cases of children diagnosed with ASD and who also present ADHD-like symptoms and/or SIB and/or other heteroaggressive behaviors or irritability and impulsivity treated with low doses of fluoxetine are presented.
Case 1 
An 8-year-old girl (19 kg) had an ASD diagnosis according to the DSM-5 and ADI-R criteria based on information provided by parents. She also had significant mental retardation, with severe SIB (banging her head against objects and biting her hands), forcing her entourage to maintain a daily and permanent physical restraint. She spends most of her time in a day hospital. She received the following pharmacological treatment: risperidone 2 mg/d and cyamemazine 80 mg/d without modifications to her SIB and at the price of a major slowing down and a manifestation of a tendency toward blunting. The CGI severity of illness score was at five (markedly ill). We decreased and stopped risperidone and started valproic acid. After four weeks of valproic acid 400 mg/d in combination with cyamemazine (60 mg/day), SIBs did not improve. Then, we added fluoxetine 2.5 mg/d and increased it after one week to 5 mg/d and to 10 mg/d in the third week. After one week, the CGI improvement scale (CGI-I) was at two; after three weeks, it lowered to 1 (very much improved). We also observed a significant decrease in anxiety as well as the disappearance of SIB (disappearance of the behavior consisting of the banging and rubbing her head against objects). However, it should be noted that the entourage kept the bandages on her hands because she continued to bite them, even if she did it with less intensity than before. There were no side effects. After three months of fluoxetine, her clinical state remains stable.

Case 2 
A 12-year-old boy (70 kg), with DSM-5 criteria for an ASD and ADI-R confirming this diagnosis, exhibited extreme irritability, violence, and impulsiveness as well as SIB (he had thrown seven television sets out of the window). The CGI severity illness scoring was at six (severely ill). In the day hospital where he spent most of his time, it was difficult for staff to manage his impulsivity and unpredictability. His treatment included risperidone 4 mg/d as well as loxapine 80 mg/d. Despite this pharmacological treatment, episodes of aggression and SIBs continued. This treatment induced a significant weight gain (8 kg in 5 months). Treatment with fluoxetine 2.5mg/d was introduced and increased to5mg/d after one week and to 10 mg/d at the beginning of the third week. After one week, there was a CGI-I score of three, which decreased to two after two weeks of treatment and to one after three weeks. Such a positive clinical response allowed for a reduction in risperidone to 2mg/d and in loxapine to 60 mg/d. The treatment was tolerated well by the patient, and he began to lose weight (4 kg). After two months off luoxetine, his clinical state remains stable.

Case 3
 A 6-year-old male child (30 kg) with DSM-5 criteria and ADI-R for an ASD exhibited problems of SIB and repetitive behaviors (washing his hands for more than 30 minutes at least two to three times per day), severe irritability, frequent crying, social withdrawal, and inappropriate speech. Treatment with risperidone 2mg/d had improved irritability and partially the SIB, but it had also produced significant weight gain (four kg in three months). A decrease in the risperidone dosage seemed necessary. Treatment with fluoxetine2.5mg/d was begun, which quickly led to a reduction in inappropriate behavior (for example, impulsive crawling on the ground in the classroom). After one week, the CGI-I scoring was at two. The dosage was gradually increased to 5 mg/d the second week and to 7.5mg/d the third week. The repetitive behaviors gradually subsided. After three weeks the CGI-I score was at one, and it remained stable for nine weeks. The risperidone dosage could be decreased to 0,5 mg/day and the patient’s weight remained the same.
Case 4 
A 12-year-old boy (62kg) withDSM-5 and ADI-R criteria for a severe case of ASD, including severe ADHD-like symptoms, often required physical restraint and did not improve despite a long-term treatment of risperidone 3 mg/d as well as melaton in 4mg at bedtime. The CGI severity illness scoring was at 6 (severely ill). The behavioral pattern included irritability, marked agitation, crying, severe hyperactivity, and other behaviors typical of this disorder. He was also anxious, rendering the situation at his day hospital where he spent most of his time all the more difficult. A prescription of fluoxetine 2.5mg/d was initiated with an immediate and complete improvement of ADHD-like symptoms:CGI-I at one week of treatment was at a one, making this case the most remarkable of the four presented here. Treatment with fluoxetine was continued with a dosage increase up to 5 mg/d to allow for a decrease in the risperidone dose to 1 mg/d. CGI-I score remained stable at one for the duration of the nine weeks.

Our reader Mira, whose son has FXS, recently referred to Dr Hagerman’s trial of low dose Sertaline/Zoloft in Fragile X. GABAA malfunction appears to be a feature of Fragile X, but it is not necessarily the identical malfunction to those with idiopathic autism who respond to bumetanide.

Objective

Observational studies and anecdotal reports suggest sertraline, a selective serotonin reuptake inhibitor (SSRI), may improve language development in young children with fragile X syndrome (FXS). We evaluated the efficacy of six months of treatment with low-dose sertraline in a randomized, double-blind, placebo-controlled trial in 52 children with FXS ages 2–6 years.


Results

Eighty-one subjects were screened for eligibility and 57 were randomized to sertraline (27) or placebo (30). Two subjects from the sertraline arm and three from the placebo arm discontinued. Intent-to-treat analysis showed no difference from placebo on the primary outcomes: the Mullen Scales of Early Learning (MSEL) expressive language age equivalent and Clinical Global Impression-Improvement (CGI-I). However, analyses of secondary measures showed significant improvements, particularly in motor and visual perceptual abilities and social participation. Sertraline was well tolerated, with no difference in side effects between sertraline and placebo groups. No serious adverse events occurred.

Conclusion

This randomized controlled trial of six-months of sertraline treatment showed no primary benefit with respect to early expressive language development and global clinical improvement. However, in secondary, exploratory analyses there were significant improvements seen on motor and visual perceptual subtests, the Cognitive T score sum on the MSEL, and on one measure of Social Participation on the Sensory Processing Measure–Preschool. Further, post hoc analysis found significant improvement in early expressive language development as measured by the MSEL among children with ASD on sertraline. Treatment appears safe for this 6-month period in young children with FXS, but we do not know the long-term side effects of this treatment. These results warrant further studies of sertraline in young children with FXS using refined outcome measures, as well as longer term follow-up studies to address long-term side effects of low-dose sertraline in early childhood.


Neurosteroid biosynthesis down‐regulation and changes in GABAA receptor subunit composition: a biomarker axis in stress‐induced cognitive and emotional impairment

By rapidly modulating neuronal excitability, neurosteroids regulate physiological processes, such as responses to stress and development. Excessive stress affects their biosynthesis and causes an imbalance in cognition and emotions. The progesterone derivative, allopregnanolone (Allo) enhances extrasynaptic and postsynaptic inhibition by directly binding at GABAA receptors, and thus, positively and allosterically modulates the function of GABA. Allo levels are decreased in stress-induced psychiatric disorders, including depression and post-traumatic stress disorder (PTSD), and elevating Allo levels may be a valid therapeutic approach to counteract behavioural dysfunction. While benzodiazepines are inefficient, selective serotonin reuptake inhibitors (SSRIs) represent the first choice treatment for depression and PTSD. Their mechanisms to improve behaviour in preclinical studies include neurosteroidogenic effects at low non-serotonergic doses. Unfortunately, half of PTSD and depressed patients are resistant to current prescribed 'high' dosage of these drugs that engage serotonergic mechanisms. Unveiling novel biomarkers to develop more efficient treatment strategies is in high demand. Stress-induced down-regulation of neurosteroid biosynthesis and changes in GABAA receptor subunit expression offer a putative biomarker axis to develop new PTSD treatments. The advantage of stimulating Allo biosynthesis relies on the variety of neurosteroidogenic receptors to be targeted, including TSPO and endocannabinoid receptors. Furthermore, stress favours a GABAA receptor subunit composition with higher sensitivity for Allo. The use of synthetic analogues of Allo is a valuable alternative. Pregnenolone or drugs that stimulate its levels increase Allo but also sulphated steroids, including pregnanolone sulphate which, by inhibiting NMDA tonic neurotransmission, provides neuroprotection and cognitive benefits. In this review, we describe current knowledge on the effects of stress on neurosteroid biosynthesis and GABAA receptor neurotransmission and summarize available pharmacological strategies that by enhancing neurosteroidogenesis are relevant for the treatment of SSRI-resistant patients. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc.

Too little allopregnanalone can induce autism.


Results
Autism spectrum disorder (ASD) is a neurodevelopmental disorder with core symptoms of social impairments and restrictive repetitive behaviors. Recent evidence has implicated a dysfunction in the GABAergic system in the pathophysiology of ASD. We investigated the role of endogenous allopregnanolone (ALLO), a neurosteroidal positive allosteric modulator of GABAA receptors, in the regulation of ASD-like behavior in male mice using SKF105111 (SKF), an inhibitor of type I and type II 5α-reductase, a rate-limiting enzyme of ALLO biosynthesis. SKF impaired sociability-related performance, as analyzed by three different tests; i.e., the 3-chamber test and social interaction in the open field and resident-intruder tests, without affecting olfactory function elucidated by the buried food test. SKF also induced repetitive grooming behavior without affecting anxiety-like behavior. SKF had no effect on short-term spatial working memory or long-term fear memory, but enhanced latent learning ability in male mice. SKF-induced ASD-like behavior in male mice was abolished by the systemic administration of ALLO (1mg/kg, i.p.) and methylphenidate (MPH: 2.5mg/kg, i.p.), a dopamine transporter inhibitor. The effects of SKF on brain ALLO contents in male mice were reversed by ALLO, but not MPH. On the other hand, SKF failed to induce ASD-like behavior or a decline in brain ALLO contents in female mice. These results suggest that ALLO regulates episodes of ASD-like behavior by positively modulating the function of GABAA receptors linked to the dopaminergic system. Moreover, a sex-dependently induced decrease in brain ALLO contents may provide an animal model to study the main features of ASD.



Results
Some steroids, whose levels are raised in autism (allopregnanolone, androsterone, pregnenolone, dehydroepiandrosterone and their sulfate conjugates) are neuroactive and modulate GABA, glutamate, and opioid neurotransmission, affecting brain development and functioning. These steroids may contribute to autism pathobiology and symptoms such as elevated anxiety, sleep disturbances, sensory deficits, and stereotypies among others.

Tuning the Brain
I did write a post a while back to show the effect of tuning GABAa receptors.




The effect of allopregnanolone of KCC2 expression and hence the level of chloride within neurons.

Neonatal allopregnanolone or finasteride administration modifies hippocampal K(+) Cl(-) co-transporter expression during early development in male rats.

Abstract

The maintenance of levels of endogenous neurosteroids (NS) across early postnatal development of the brain, particularly to the hippocampus, is crucial for their maturation. Allopregnanolone (Allop) is a NS that exerts its effect mainly through the modulation of the GABAA receptor (GABAAR). During early development, GABA, acting through GABAAR, that predominantly produces depolarization shifts to hyperpolarization in mature neurons, around the second postnatal week in rats. Several factors contribute to this change including the progressive increase of the neuron-specific K(+)/Cl(-) co-transporter 2 (KCC2) (a chloride exporter) levels. Thus, we aimed to analyze whether a different profile of NS levels during development is critical and can alter this natural progression of KCC2 stages. We administrated sustained Allop (20mg/kg) or Finasteride (5α-reductase inhibitor, 50mg/kg) from the 5th postnatal day (PD5) to PD9 and assessed changes in the hippocampal expression of KCC2 at transcript and protein levels as well as its active phosphorylated state in male rats. Taken together data indicated that manipulation of NS levels during early development influence KCC2 levels and point out the importance of neonatal NS levels for the hippocampal development.                                                                                                                           
Conclusion

Add very low dose Prozac to the long list of possible SIB therapies, more practical than electroconvulsive therapy (ECT), that is for sure!

This post was long waiting in my “to-complete” pile. I thought it would be a short one, but it kept growing.  It does draw together several interesting issues and shows there is a pattern developing in all these blog posts.
The majority of psychiatric drugs have such severe drawbacks that the great majority of children are better off without them.  However, there are many existing drugs that have little known neurological effects that can be highly beneficial and are known to be safe to use long term.
Psychiatric drugs that can be repurposed at lower dosages for different purposes may indeed be free of the major drawbacks encountered at higher doses.
It looks like humans with Fragile X Syndrome (FXS) are leading the way with low dose SSRI therapy to modulate GABA.  It would seem highly plausible that other idiopathic autism might also benefit and the French case studies in this post are examples of those who did benefit.
I think this is another example of fine-tuning the brain to optimize its functioning. It probably will not produce miracles, but the science shows that allopregnenalone can be tuned to vary mood in humans.  Low levels of allopregnenalone can produce autistic-like behaviours in mouse models.
The effect of allopregnenalone on KCC2 expression may only be present in tiny babies, if it continues into childhood that would be another reason to consider it as a target for modulation.  If that were the case, then Finasteride the cheap generic drug for prostate enlargement, should be investigated.
As is always the case in autism, both extremes are likely to exist; some people will likely benefit from low dose SSRIs but it will make some others worse (anxiety, SIB etc). If you start with elevated allopregnenalone, you would want less, not more.
Repurposing existing drugs has huge unrealized potential.
The OTC antihistamine Clemastine, which I highlighted in an earlier post as being a Positive Allosteric Modulator (PAM) of P2X7, and so helps remyelination, is yet another example of repurposing a safe drug.  Reportedly, it has this effect even below the regular dosage for allergy; at the high dosage usage in MS trials it will send you to sleep and risk some other side effects. As MS is not a singular condition, it seems that some people respond much more so than others. It also seems to have a benefit is some psychiatric disorders; not bad for a cheap OTC antihistamine.



36 comments:

  1. https://academic.oup.com/brain/article/141/1/85/4735219

    ReplyDelete
    Replies
    1. There are plenty of reasons to think Clemastine has broad therapeutic potential. Your paper is another example.

      Delete
  2. Thank you for the great article.

    Could mirtazapine be used as well in this type of treatment?

    Here is a relevant study I found:
    https://www.researchgate.net/publication/7424930_Influence_of_mirtazapine_on_plasma_concentrations_of_neuroactive_steroids_in_major_depression_and_3a-hydroxysteroid_dehydrogenase_activity

    ReplyDelete
    Replies
    1. There certainly is an overlap in the effect of low dose SSRI and mirtazapine.

      One reader of this blog reported that a smallish dose of mirtazapine produced a remarkable benefit in their child. The standard dose as an antidepressant is 30mg, I think he was using 4 or 5mg.

      The problem with Mirtazapine (Remeron) is that it has numerous effects on different receptors and the net effect varies with the dosage. At a very low dose it is a potent H1 antihistamine and it is very sedating. At higher doses there is another effect which is pro-alertness which counters the sedative effect of the H1 receptors in the brain.

      I think the low dose SSRI is likely the simplest, safest and most selective route.

      Delete
    2. Appreciate your reply.

      Yes, comparing the two, definitely agree on SSRI being the most precise.

      Delete
  3. Never tried a low dose SSRI before for this reason but on multiple boards forum there seems to interest in doing so to raise neurosteroid levels.
    However I have personally tried a low dose pregnonolone (5mg I believe it was) and felt rather odd (headache for around 3hours) then afterwards nothing.
    DHEA I have also tried (I believe it was 25mg) which also gave me headaches and no benefit.
    Now pregnenolone can be stored in the form of pregnenolone sulfate which is a NMDA potentiator and possibly giving me headaches through this pathway. Another possibility is that pregnenolone in my case gets shifted more towards testosterone production rather than progesterone production (and downstream allopregnenolone).

    In fact I believe that a low dose progesterone would be a wiser option than pregnenolone, progesterone also has a positive effect on gaba receptors for autism (it acts as an anticonvulsant). On top of that (atleast me personally) seem to do very well on herbal phyto-progestins (damiana and such).

    Also progesterone is one stop closer towards allopregnenolone than pregnenolone is. Read it up, theres multiple reports of adverse effects of pregnenolone supplementation, after it all the most basic of all hormones (it serves as a precursor to all of them).

    Im not sure if classic autism will benefit from progesterone aswell (there are multiple studies showing it can be good and multiple showing that prenatal progesterone exposure induces autism like symptoms, very weird and odd all).

    Anyhow...

    Reduced Maladaptive Behavior and Improved Social Function in a Child with PDD-NOS Treated with Progesterone
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3134438/

    On top of that it should be said that progesterone itself also has an influence on serotonin function and not just gaba function, for example it actually increases sertonin transporter expression and 5ht2a expression and decreasing 5ht1a expression.
    Basically progesterone seems an 'antidote' for high serotonin.

    ReplyDelete
  4. Latest paper on neuroinflammation and ion channel dysfunction:

    "We thus set out to test whether that a “pure” neuroinflammatory response induced by [..] lipopolysaccaride [..], could induce brain channelopathies. We focused on HCN channels as a model system because they are modified in CNS disorders associated with inflammatory conditions
    [..]
    Here, we report that intracerebroventricular injection of the prototypical inflammatory molecule lipopolysaccharide (LPS) in rats triggered a strong and long lasting inflammatory response in hippocampal microglia associated with a concomitant up-regulation of Toll-like receptor (TLR4) in pyramidal and hilar neurons. This, in turn, was associated with a significant reduction of the dendritic hyperpolarization-activated cyclic-AMP gated channel type 1 (HCN1) protein level.
    [..]
    HCN channels also play a key role in controlling dendritic integration in hippocampal CA1 pyramidal cells. The high density of Ih in distal dendrites attenuates the temporal summation of excitatory inputs and dampens neuronal excitability by decreasing the input resistance. Importantly, Ih tunes the membrane to respond optimally to inputs in the theta frequency band, a brain rhythm central to numerous cognitive processes. Therefore, alterations in HCN function may lead to network dysfunctions implicated in hyperexcitabilty and cognitive deficits."
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6070409/

    /Ling

    ReplyDelete
    Replies
    1. Ling, I am myself currently thinking about HCN channels.

      It looks particularly for people with a RASopathy like NF1, that an HCN agonist should help cognition.

      HCN channels are a novel therapeutic target for cognitive dysfunction in Neurofibromatosis type 1.
      https://www.ncbi.nlm.nih.gov/pubmed/25917366

      That would suggest people who respond to a PAK1 inhibitor (FRAX486, BIO 30, Ivermectin etc) might respond to an HCN agonist.

      People with seizures who take lamotrigine are already taking an HCN channel agonist.

      The ketone BHB is an HCN agonist.

      Delete
  5. Could salt water and oxygen in a special combination actually treat myelination issues in MS?
    This article says so:

    "The current study highlights the stimulation of myelin-specific gene expression in oligodendrocytes by RNS60 that contains charge-stabilized nanostructures. RNS60 also stimulated the expression of myelin-specific genes in mixed glial cells without altering the expression of GFAP, an astrocyte-specific marker, suggesting that the effect of RNS60 is oligodendroglia-specific. This is unique because RNS60, a saline-based agent, is devoid of any active pharmaceutical ingredient, and hence is not targeted to a specific protein. Moreover, two important controls RNS10.3 (saline processed without elevated level of oxygen) and PNS60 (unprocessed saline with the same elevated oxygen concentration as RNS60) did not exhibit myelin gene stimulating effect, suggesting that the bioactivity of RNS60 is based neither on processing nor oxygen content alone, but a combination of the two."
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5799355/

    Maybe not a very useful link, but a little bit thought provoking.

    /Ling

    ReplyDelete
    Replies
    1. Ling, on the subject of myelination, I think people whose autism suggests an overly thin myelin layer might consider a half dose of Clemastine for a couple of months. It is an OTC antihistamine, at least in some EU countries, and at 0.5mg a day is cheap. There is scientific and anecdotal evidence to support it.

      Delete
  6. Would be interesting to see how I will respond to donepezil too (especially considering its a sigma1 agonist).
    This paper was posted on reddit earlier, sigma1 ligands are an interesting target especially since endogenous (neuro)steroids are agonists and antagonists of sigma1 receptors, including pregnenolone sulphate (agonist), progesterone (antagonist).

    Sigma-1 receptor ligands control a switch between passive and active threat responses
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4912403/

    ReplyDelete
  7. Thanks for this article.
    After the birth of my daughter, I experienced pretty bad post-partum depression, and asked to be put on a low-dose of Prozac (I was breast-feeding). They gave me 5 mg/day. I had known for many years that I often responded well to micro-/low doses of medications and felt I would probably get a positive response from this low dose.

    I stayed on 5 mg of Prozac for about one year... I noticed at about at the 9 month marker that I was feeling much less creative, and a bit slow and thick-thinking. I stopped at about 12 months, and my creative/fast-thinking/thought processes came back (with great relief to me). I also was not depressed.

    I don't think my doctor or gynecologist or therapist believed that 5 mg. was effective, but I found relief within 24-hours of my first dose. The memory is still quite vivid all these years later.

    ReplyDelete
    Replies
    1. Silverseas I believe you,

      While not all SSRI's increase neurosteroids at low doses, the effect of first starting SSRI treatment (it takes 2 weeks to downregulate the 5ht1a autoreceptor in the DRN) I also strongly felt. In fact the first 2 weeks of treatment actually induces a low serotonin/high dopamine state. This is because activating the 5ht1a autoreceptor actually DECREASE serotonin content in the brain, its like a gating mechanism.

      You might find this interesting:

      Lower allopregnanolone during pregnancy predicts postpartum depression: An exploratory study.
      https://www.ncbi.nlm.nih.gov/pubmed/28278440

      https://www.scientificamerican.com/article/an-entirely-new-type-of-antidepressant-targets-postpartum-depression/

      http://fortune.com/2018/11/02/fda-poised-to-approve-zulresso-brexanolone-postpartum-depression-drug/
      The FDA Is Poised to Approve the First-Ever Postpartum Depression Drug (basically allopregnenolone)

      This was very recently (early november)

      Delete
    2. Silverseas to get back to you once more, I just found this:

      High occupancy of sigma-1 receptors in the human brain after >>> SINGLE ORAL administration of fluvoxamine <<<: a positron emission tomography study using [11C]SA4503. Biol Psychiatry 62(8):878–883
      https://www.ncbi.nlm.nih.gov/pubmed/17662961

      The study demonstrated that fluvoxamine bound to sigma-1 receptors in living human brain at therapeutic doses. These findings suggest that sigma-1 receptors may play an important role in the mechanism of action of fluvoxamine.

      Delete
    3. Aspie1983-- Thanks so much for the links/info. It will take me a while read them.

      Delete
  8. Been reading up on sphingolipids (something you seem to have never discussed yet Peter), they are lipids that acts as messengers and are indeed implicated in autism. Here is one such study:

    Potential serum biomarkers from a metabolomics study of autism
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4688025/

    We included 73 patients and 63 controls in the discovery cohort and 100 cases and 100 controls in the validation cohort. Metabolomic analysis of serum in the discovery stage identified 17 metabolites, 11 of which were validated in an independent cohort. A multiple logistic regression model built on the 11 validated metabolites fit well in both cohorts. The model consistently showed that autism was associated with 2 particular metabolites: >>> sphingosine 1-phosphate <<< and docosahexaenoic acid.

    Multiple Roles for Sphingolipids in Steroid Hormone Biosynthesis (including neurosteroids)
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4104360/

    The sigma1 receptor interacts with N-alkyl amines and endogenous sphingolipids
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3194046/

    Sigma-1 receptor: The novel intracellular target of neuropsychotherapeutic drugs
    https://www.sciencedirect.com/science/article/pii/S134786131400022X

    "The unique hydrophobic environment of the ligand-binding site may be enabling hydrophobic molecules to associate with the binding site. Indeed, the most sigma-1 receptor ligands possess hydrophobic or amphipathic property (e.g., haloperidol and fluvoxamine) (1), (5). Postulated endogenous ligands of the sigma-1 receptor include steroids (e.g., progesterone, DHEA-sulfate), hallucinogen N,N-dimethyltrypatamine, and sphingosine (15), (16), (17). Furthermore, a recent study suggested a possibility that monoglycosylated ceramide might possess a high affinity for the sigma-1 receptor (18). Among sigma-1 receptor-binding lipids, steroids (e.g., progesterone and testosterone, DHEA) seem to have relatively low affinities (0.3–10 μM) when compared with those of endogenous sphingolipids and monoglycosyated ceramides (15), (17), (18). Certain sphingolipids appear to possess affinities high enough to bind sigma-1 receptors at their physiologically relevant concentrations."


    Sphingolipids: membrane microdomains in brain development, function and neurological diseases
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451547/

    Probiotics:

    Sphingolipids as Mediators in the Crosstalk between Microbiota and Intestinal Cells: Implications for Inflammatory Bowel Disease
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5021499/

    Ceramide for example was shown to be a tlr4 agonist (reuteri atcc 6475 is an antagonist)

    ReplyDelete
  9. Sphingosine-1-Phosphate Metabolism and Its Role in the Development of Inflammatory Bowel Disease
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5412326/

    This study and multiple others think that sphingosine (but sphingosine 1-phosphate) are ligands for the sigma-1 receptor.

    Remember my very negative experience with vitamin k2 mk4/mk7 before? turns out that these 2 specific forms of vitamin k are very unique and brain specific, one of the reasons due to my bad response is the elevation of tissue plasminogen activator. However they also seem to modulate sphingolipids! Phosphatidylserine and alpha gpc (Alpha glycerylphosphorylcholine) are highly involved in sphingolipids.

    Also unraveling the mystery of vitamin b6/p5p in autism (why mega doses are needed often in a seemingly deficient state, yet again not always)?
    Look here:

    PLP-dependent enzymes as entry and exit gates of sphingolipid metabolism.
    https://www.ncbi.nlm.nih.gov/pubmed/21710479

    !!!
    Regulation of oxytocin receptor expression in cultured human myometrial cells by fetal bovine serum and lysophospholipids.
    https://www.ncbi.nlm.nih.gov/pubmed/12488330

    "ranscriptional activity of the OTR gene was the same with or without FBS treatment, but FBS increased OTR mRNA half-life about 5-fold. Lysophospholipids (>>>>>> lysophosphatidic acid and sphingosine 1-phosphate <<<<<<), which are present in serum, had similar effects as FBS."

    Gintonin in panax ginseng contains a recently discovered natural LPA ligand

    Gintonin, newly identified compounds from ginseng, is novel lysophosphatidic acids-protein complexes and activates G protein-coupled lysophosphatidic acid receptors with high affinity.
    https://www.ncbi.nlm.nih.gov/pubmed/22286231

    ReplyDelete
    Replies
    1. Aspie1983, I guess I'm the sphingolipid gal here. The whole subject of different lipids is huge, and it's not obvious which ones are working at what direction, at least not in the brain.
      Look for posts on buttermilk, MFGM or AUTS2 here on the blog to find some of the previous conversation.
      If I remember it right, phosphatidylserine is one part of sphingolipids but there are other less known ones worth researching. PKC looks like an important target for them.

      I've currently added buttermilk to our interventions, but since my daughter has a tooth coming up right now nothing is normal.
      On the subject of that Peter, did you have any suggestions except for Sytrinol (which didn't work very well last time) or statins for teething issues?

      /Ling

      Delete
    2. Hi Ling,
      Yep, I seem to have dramatic responses to alpha gpc (drastic increase in imagination), phosphatidylserine (relaxation and social calmness).
      As stated before however I also seem to get bad side effects especially from alpha gpc (acne and tenderness is my nipple area), what I found striking about alpha gpc is that in studies it raises free fatty acids + ketones ~2hour after intake (t+2hours after intake of 600mg alpha gpc I also noticed a drastic increase in mood) as you might know all my bloodtest showed LOW triglycerids (below bottom range). It is very obvious to me that my body seems to be unable to normall process lipids. also alpha gpc can lower TSH and im subclinical hypothyroid (on levothyroxine for that too).

      Phosphatidylserine helps me, it helps me A LOT in fact but... it seemed to be giving me fordyce lately, which is unacceptable for me, it was either due to combination with ginkgo + pqq or ginkgo + phosphatidylserine + pqq. PQQ im also a drastic responder to but always gives me side effects... it really sucks, when I tried it over a year ago I also had the side effects coming ~10days after starting.
      23andme also states that I have a decreased conversion from phosphatidylcholine into something else, so there is definetely a genetic problem atleast for me.
      Also krilloil which contains dha bound phospholipids gave me mania like energy and mood, but also seemed to give some immune activation/modulation and whenever that happens I always seem to get pains around my lymphnodes, back of my head/neck (oddly always around the area of my head where the cerebellum is located) and earpain/ear infections. Astragalus (immune activator) and Suma root (another immune activator) feel identical.

      Also Ive tried colostrum a few times with limited success, im quite scared to take it again as it also contains so many peptides and growth factors it might be ending up stimulating my immunesystem in a bad way, afaik colostrum also is a rich source of MFGM.

      Also phosphatidic acid as a supplement (this is a sports supplement has an extremely calming effect on me similar to how damiana feels, allowing others to come close to me so to speak), phosphatidic acid and DAG (peanutbutter) are interchangable and are in the PKC/IP3 pathway. Soy lecithin (filled to the max with phospholipids) also I respond to in the past, but all phospholipids seem to give me stomach problems (well known cholinergic effect as choline activity in the gut control naussea/cramping/contractions, where as vomiting is controlled by 5ht3a receptors).

      Delete
    3. And yep Ling, my body seems to respond well to PKC and PLC induction which both downstream increase IP3 release and regulates 5ht2a activity.
      sigma-1 also regulates PLC signalling.

      Also Ive recently (around 10 days ago) started with panax ginseng to help with my adhd problems (low dopamine) and I feel as it is helping really a lot with my anhedonia. In fact I find panax ginseng better than ritalin.
      A common overlap between most herbals that I seem to prefer is that most of them have an antagonistic effect on brain serotonin levels and some of them potentiate 5ht2a signallin. Panax ginseng for example has been shown to inhibit TPH synthesis, nitric oxide and arginine also inhibits TPH.
      Panax ginseng and eleuthero (siberian ginseng) are also progesteron and estrogen binding ligands.
      https://doi.org/10.1507/endocrj1954.29.567

      Anyhow I will wait till my psych gets back from holiday and then try donepezil, I got high expectations from that since its a potent sigma-1 ligand.

      High occupancy of σ1 receptors in the human brain after single oral administration of donepezil: a positron emission tomography study using [11C]SA4503
      https://academic.oup.com/ijnp/article/12/8/1127/678305

      "Doses of 5 mg and 10 mg donepezil bound to σ1 receptors in the human brain with occupancies of ∼60% and ∼75%, respectively, in a dose-dependent manner. This study demonstrated that donepezil binds to σ1 receptors in the living human brain at therapeutic doses. Therefore, σ1 receptors may be implicated in the pharmacological mechanism of donepezil in the human brain."

      Your daughter responds to phospholipids too I take it?

      Delete
    4. https://ibb.co/caWuTV

      As you can see Ling my genetic data tells me I have the highest phosphatidylcholine levels of the SNP, also problems with 18:2 fatty acids (low it seems?), which according to wikipedia are.... tada... PEANUTOIL (https://en.wikipedia.org/wiki/List_of_unsaturated_fatty_acids)
      Also my arachidonic acid levels seem higher, considering I have problems with these fatty acids, it seems pretty save to interpreter that I also have endocannabinoid problems.

      Once again, sigma-1 receptors also seem to regulate CB1 systems..

      The calcium-sensitive Sigma-1 receptor prevents cannabinoids from provoking glutamate NMDA receptor hypofunction: implications in antinociception and psychotic diseases
      https://academic.oup.com/ijnp/article/17/12/1943/2910014

      Delete
    5. Aspie1983, I wanted to thank you for the take on sigma-1 receptor, which I haven't looked into before but just now realized could have an impact on NMDAr signalling.

      It's often like this, someone posts something interesting here and I don't react until 6 months later when I start to understand it. Sometimes I even find my own comments, that I have forgotten!

      Re: Krill oil - it looks like it has an effect on ATP in hippocampus.

      By the way, are you the serotonin guy? You (or anyone else) don't happen to have a list on agonists/antagonists to different serotonin receptors... I'm also wondering if all 5HT receptors get upregulated both by agonists and antagonists.

      /Ling

      Delete
    6. Hi Ling!,

      First of all thanks and sorry for the late reply, but better late than never :).
      Not sure if you tried krilloil? I believe you did? From what I remember it was you telling me that it has an effect on p38 and RORa receptors, it felt like immune activation to me if I took more than one pill per 2 days. Keep in mind krilloil is EXTREMELY potent, atleast it was for me (also there have been reports on longecity of some people getting temporarily manic like symptoms from it showing it can have a very strong effect on serotonin).

      And yep I guess im the serotonin guy hahaha, I do not have an actual list that I keep or something but I have done tons of reading on them and also used lots of them. I seem to do well with 5ht2a agonism and serotonin antagonists, 5ht1a agonists I respond bad to.

      Delete
    7. Myself, I tried krill oil for maximum 2 weeks and didn't see any effect. My daughter can't swallow pills so I haven't been able to try it on her yet. Do you have any source to share on the krill oil effect on serotonin btw?

      Anyway, we are trying buttermilk powder (2 g daily) for two weeks now and I am seeing the same result as we saw earlier with phosphatidylserine - vivid dreams.

      If this isn't a coincidence and the result holds, it is amusing to know that you can replace your expensive bottle of PSerine with "Bob's Red Mill" Sweet Cream Buttermilk powder, intended for making American pancakes, and it will last forever!

      :-)

      /Ling

      Delete
    8. Ling, I have stopped the PS as I have said before it was either glutamine, pqq or phosphatidylserine that flared up fordyce. Pretty bad on my lip tbh probably will have to get it lasered out later on.
      So as you can imagine Im quite scared to experiment with phospholipids again.

      Regarding their efficiency: oh hell yes, they increase perception in me (something I highly search for as increasing perception in me corresponds to better social skills and empathy). Endogenous lipids are ligands for sigma-1 receptor, watch in years from now it will turn out that modulating this system is the only feasible long term option (agonism seems amplification of signalling and and antagonism means global dulling of intracellular signalling).

      Regarding studies, I cant find the one that it affects mao-a, 5ht1a and 5ht2a signalling anymore but an easy google search leads to this:

      Enhanced cognitive function and antidepressant-like effects after krill oil supplementation in rats
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3618203/

      Krill oil significantly decreases 2-arachidonoylglycerol plasma levels in obese subjects
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3048484/

      Looking at the fact that manipulates 2-AG levels one can allready tell it has a profound effect on endocannibinoids.

      Also what I have found striking regarding my own experience with substances it that when my brain signalling goes down (such as with damiana tea/pills) my empathy is better and I seem to become more introvert regarding personality. Its almost as if slowing down of perception/brain signalling allows for proper processing to occur.

      I know it was tyler or aj who recently also has emphasized this with a post and I can attest to that. I get a strong response to certain sleep like medications aswell including valerian, dramatically alters my perception (through adenosine a1 and 5ht5a).

      Delete
  10. Here is a paper about brain tumors and their effects on epilepsy symptoms that I have a hunch could be absolutely huge in the autism science space with respect to the findings regarding perineuronal nets and a novel understanding of what they do with interneurons, and in particular parvalbumin intereurons that many autism animal studies show are highly compromised.

    Press Release:

    https://www.sciencedaily.com/releases/2018/11/181109073036.htm

    Paper:

    https://www.nature.com/articles/s41467-018-07113-0

    The main finding in this paper that is relevant to autism is that perineuronal nets rather than simply promoting synaptic stability as was previously thought, also act as an insulator on neurons, especially GABAergic interneurons, that allows them to fire and supraphysiological firing rates. What this means is that if the perineuronal nets surrounding an interneuron are compromised, the interneuron will have a lower maximal firing rate. Many EEG studies for autism have consistently shown decreased gamma wave (greater than 40hz firing rate) power, and the consensus here is that this is due to decreased function of GABAergic interneurons that fire at this rate, and especially paralbumin interneurons.

    This paper of course does not draw these conclusions with respect to autism, but the correlations are strikingly obvious.

    Also, SpectrumNews discusses unpublished findings from a research group that came out last week at the Society of Neuroscience conference that specifically discusses perineuronal nets and autism:

    https://www.spectrumnews.org/news/webbing-around-neurons-altered-autism-mouse-models/

    Their findings, contrary to the hypothesis I presented above, suggest the perineuronal nets of parvalbumin interneurons are too thick in autism and that a drug which degrades them might help improve autism symptoms. Of course, it is very possible and likely that an excess or lack of perineuronal nets may vary widely in the autism brain, or that which scenario is predominant depends on autism subtype (SpectrumNews also discusses a mouse study that attempted to accomplish categorizing autism subtypes if you want to read through the recent news section of the last week).

    Last but not least, Wikipedia has a good summary of perineuronal nets if anyone is curious or never heard of them before:

    https://en.wikipedia.org/wiki/Perineuronal_net

    ReplyDelete
    Replies
    1. Hi Tyler,

      Great info, thanks very much for sharing! And I appreciate the connections you have made here - very interesting indeed.

      I hadn't seen the findings around perineuronal nets - given the function of perineuronal nets and the findings in both mouse models and iPS cells of certain related disorders, issues relating to perineuronal nets (too much or too little) could absolutely be very relevant.

      After reading up on your links, I looked a bit further into PNNs and found the following:

      https://www.biorxiv.org/content/early/2018/10/01/432419

      I wonder what impact Effexor may have on those whose condition is leading to an excess of PNNs.

      "Moreover, venlafaxine treated mice (30 mg/kg/day) show an increase in carbachol-induced gamma power in hippocampal slices."

      Also, the page on Spectrum News around SfN2018 is terrific - another great item you kindly shared. I went on SfN2018's site, and found the following page that allows us to look at the abstracts from the conference in PDF. Tons of info, and I bet a few gems in there.

      http://www.sfn.org/Meetings/Neuroscience-2018/Abstracts/Neuroscience-2018-Abstracts

      One fascinating thing I saw in the Wikipedia page you linked: "PNNs play a critical role in the closure of the childhood critical period, and their digestion can cause restored critical period-like synaptic plasticity in the adult brain."

      Thanks for sharing Tyler, lots of great info and an interesting avenue (Perineuronal nets) that I hadn't looked much into before.

      Have a great night Tyler!

      AJ

      Delete
    2. Am I deducing right that an EEG would be able to point in the direction whether there is an excess or lack? We never did EEG and I have myself compiled several studies but am unable to find someone who would be able to look at my daughters EEG and the papers and sort of form a conclusion as to what her results mean. Since my daughter is on track for Duke, I found this paper especially interesting: https://stemcellsjournals.onlinelibrary.wiley.com/doi/full/10.1002/sctm.18-0090

      Delete
    3. Most EEGs are basically useless above 20hz or so, even though some of the commercial dry sensor ones claim to be able to detect gamma and even lambda waves which is sort of a joke. Reliable detection of gamma waves requires a research grade setup and then a lot of computing horsepower to filter out the noise from the recordings so as to get useful information in the gamma band.

      Also, while GABAergic interneuron dysfunction seems to be the cause of reduced gamma power in many people with autism spectrum disorders, there is no consensus as to what is driving that dysfunction whether it is a glutamate receptor issue on the interneuron, a lack of receptors, a lack of dendrites hooking up to the axons of pyramidal neurons which drive them and gamma rhythms, something wrong somatically with the interneuron, an ion channel dysfunction, or a myriad of other potential reasons. Perineuronal nets rather could be just one of the possibilities.

      Delete
    4. Thanks Tyler - I had never heard about these perineuronal nets before. Fascinating!

      /Ling

      Delete
  11. Anyone who wants to know "everything" on KCC2 but only want to read one paper should probably read this recent review:

    Chloride transporters and GABA polarity in developmental, neurological and psychiatric conditions

    https://www.sciencedirect.com/science/article/pii/S0149763418300149?via%3Dihub

    Regular readers of the blog might find that they knew almost everything already, but eventually there are small stones that we haven't turned yet... There is an excellent Figure 1 too, for those who don't even want to read one article. ;)

    /Ling

    ReplyDelete
    Replies
    1. The above paper made me interested in how PKC contributes to KCC2 upregulation.

      So, there are 15 variants of PKC, divided into three groups: classical (or conventional), novel and atypical. All groups respond to phosphatidylserine, but the first group also needs Ca2+ and DAG and the second needs DAG in addition to PS.
      Each PKC has its own range of effects, like muscle memory or allergy or PTSD or KCC2. I recommend a look at Wikipedia on PKC variants for a quick orientation: https://en.m.wikipedia.org/wiki/Protein_kinase_C

      I have mostly looked at the atypical variants so far, PKCzeta for example could be relevant for apraxia.

      Anyway, for KCC2 it looks like at least PKCalpha and PKCepsilon regulate KCC2 positively. I haven’t looked into corresponding substances, but bryostatin might be beneficial: https://www.ncbi.nlm.nih.gov/m/pubmed/24637095/

      As an anecdote, I get less stressed when using phosphatidylserine, but the effect doesn't feel like it is of the magnitude that could change autism.

      /Ling

      Delete
    2. Ling very interesting!

      I would like to add that I also have had a good experience with phosphatidic acid, in fact a combination of both phosphatidylserine and phosphatidic used to be available as a supplement (see my post history):
      Effects of soy lecithin phosphatidic acid and phosphatidylserine complex (PAS) on the endocrine and psychological responses to mental stress.
      https://www.ncbi.nlm.nih.gov/pubmed/15512856

      A soy-based phosphatidylserine/ phosphatidic acid complex (PAS) normalizes the stress reactivity of hypothalamus-pituitary-adrenal-axis in chronically stressed male subjects: a randomized, placebo-controlled study.
      https://www.ncbi.nlm.nih.gov/pubmed/25081826

      I would like to point out that both PS and PA are mTOR activators btw (keep in mind there are many subtypes of mTOR and even agmatine activates mTOR, so its not that easy to say that either mtor = good or bad).

      Alsooooo phosphatidic acid can be interchanged to DAG (I posted about this over a year ago btw, but people seems to keep ignoring me back then, oh well their loss).

      Regulation of PDE-4 cAMP phosphodiesterases by phosphatidic acid.
      https://www.ncbi.nlm.nih.gov/pubmed/9631235

      Complex but also seems to influence opioid binding/tolerance:

      Enhancement of opiate binding by various molecular forms of phosphatidylserine and inhibition by other unsaturated lipids.

      Role of phospholipase D2/phosphatidic acid signal transduction in micro- and delta-opioid receptor endocytosis.
      https://www.ncbi.nlm.nih.gov/pubmed/20354103

      "Taken together, our results revealed that the regulation of opioid receptor endocytosis by PLD2 involves the conversion of its product PA to DAG resulting in an activation of the p38 MAPK pathway."

      Enhancement of opiate binding by various molecular forms of phosphatidylserine and inhibition by other unsaturated lipids.
      https://www.ncbi.nlm.nih.gov/pubmed/69441

      "The addition of acidic phospholipids such as phosphatidylserine, phosphoinositides, and phosphatidic acid significantly enhanced opiate binding. With the exception of phosphatidylserine, when the acidic phospholipids contained a polyunsaturated acyl group, they were actually inhibitory, along with neutral phospholipids derived from brain. Both the C18:0, C18:1 form (derived from myelin) and the C18:0, C22:6 form of phosphatidylserine (derived from synaptic membranes) produced as much as a 45% enhancement in opiate binding."

      Role of Phospholipase D2/Phosphatidic Acid Signal Transduction in μ- and δ-Opioid Receptor Endocytosis
      http://molpharm.aspetjournals.org/content/78/1/105

      "Taken together, our results revealed that the regulation of opioid receptor endocytosis by PLD2 involves the conversion of its product PA to DAG resulting in an activation of the p38 MAPK pathway"

      Back to sigma-1 receptors (very underlooked imo in autism, it will turns out that it all comes down to improper immune/gut homeostasis)

      Knockdown of interleukin-10 induces the redistribution of sigma1-receptor and increases the glutamate-dependent NADPH-oxidase activity in mouse brain neurons
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4599652/

      Conclusions
      It has been concluded that IL-10 deprivation, at least in part, can lead to the induction of ER-stress, which causes BiP expression and SigR1 redistribution between components of endoplasmic reticulum (ER) and plasma membrane. Moreover, IL-10 deficiency can change the specific organization of NMDAR, increasing the surface expression of SigR1-sensitive NR2B-containing NMDAR. -->>In these conditions, glutamate-dependent ROS production is greatly increased leading to the initiation of apoptosis. In this circumstances, sigma-ligands could play a preventive role against NMDA receptor-mediated excitotoxicity.<<--

      Delete
  12. And since I love simple figures that tell me more than 5 articles, I wanted to share this one:

    https://i0.wp.com/www.neurology.org/content/68/12/945/F1.large.jpg

    It shows the cascade from pregnenolone synthesis in mitochondria to most of its derivatives (estradiol and allopregnanolone at the bottom) and how they affect both NMDA receptors and GABAa receptors.
    Of course, it doesn't show the small details like subunits, but I found it very educational for a newbie on sex hormones/neurosteroids.

    /Ling

    ReplyDelete
  13. Hello Peter and all,

    Bumetanide has stopped being produced here in my country. Do you think that Furosemide would be equivalent ? (I've read that 40 mg of Furosemide is equivalent to 1 mg of Bumetanide.)
    Thanks for any input !

    ReplyDelete
    Replies
    1. Luis, Furosemide is very similar to bumetanide but there is an important difference which means it will not be as effective. Both drugs reduce the flow of chloride into neurons, but Furosemide also reduces the flow out by blocking KCC2.

      In Mexico they sell bumetanide as Miccil and in Spain it called Fordiuran. Both seem very easy to access if you have a friend or relative who goes to either country.

      Delete

Post a comment