I read into the pssd forum and the conesus is that presynaptic 5-ht1a receptors are desentitated but I personally have some difficulties to accept it to 100%
If so, then You should have overall increased 5-ht to a same degree, thus making You less or more anxious, alter perhaps Your sleep & etc.
 
Aynway it seems that the causes of 5-ht1a desentitation differ among the SSRI´s
 
Chronic administration of venlafaxine fails to attenuate 5-HT1A receptor function at the level of receptor-G protein interaction.
However, the lack of effect of chronic sertraline treatment on 5-HT1A receptor-stimulated [35S]GTPgammaS binding is in contrast to what has been observed previously following chronic administration of the SSRI fluoxetine, and suggests that different SSRIs may regulate somatodendritic 5-HT1A autoreceptor function differently depending on their pharmacology.
Our data also suggest that the desensitization of somatodendritic 5-HT1A autoreceptors observed in electrophysiological studies following chronic venlafaxine administration is not at the level of receptor-G protein interaction.
http://www.ncbi.nlm....pubmed/16035959
 
however some say that the cause is not at the g-protein level:
 
Effects of chronic treatment with escitalopram or citalopram on extracellular 5-HT in the prefrontal cortex of rats: role of 5-HT1A receptors
Therefore, it appears that 5-HT1A autoreceptor desensitization plays a minor role in enhancing the effect of chronic SSRI on extracellular 5-HT. It remains to be established whether other adaptive changes occurring after chronic treatment with SSRIs such as the desensitization of terminal 5-HT1B receptors or of the NMDA receptors controlling 5-HT release (Nowak et al., 1996; Pallotta et al., 2001) contribute to the enhancement of extracellular 5-HT.
http://www.ncbi.nlm....les/PMC1574969/
 
This one has some further suggestions but the g-protein might be altered according to them:
 
Regulation of 5-HT1A receptor function in brain following agonist or antidepressant administration.
Region-specific differences in the regulation of 5-HT(1A) receptor function may be based on compensatory changes distal to the receptor, such as regulatory changes at the level of effector (e.g. adenylyl cyclase or ion channel), or at the level of the G protein such as changes in G protein expression, or phosphorylation of the G protein. It may be that the increase in serotonin neurotransmission, due to somatodendritic autoreceptor desensitization following agonist or antidepressant treatment, to normo-sensitive 5-HT(1A) receptors in certain brain regions (e.g. hippocampus or cortex) and to sub-sensitive 5-HT(1A) receptors in other brain regions (e.g. amygdala or hypothalamus) underlies the therapeutic efficacy of these drugs.
http://www.ncbi.nlm....pubmed/12559389
 
Btw: according to the escitalopram/citalopram paper above, desentitation doesnt occured in rat which where anesthenized, so perhaps therefore are some results contrary
 
This one states again something different:
 
Differential regulation of serotonin-1A receptor stimulated [35S]GTPγS binding in the dorsal raphe nucleus by citalopram and escitalopram
Although citalopram and escitalopram have been shown to desensitize somatodendritic 5-HT1A autoreceptors, our data suggest that the mechanism(s) of desensitization may differ.
Perhaps the differences between the effects of chronic administration of citalopram or escitalopram on the regulation of 5-HT1A receptor function in the dorsal raphe nucleus may
be accounted for by allosteric modulation of the action of escitalopram by R-citalopram. It is not unreasonable to propose that longer binding to and therefore greater inhibition of the
serotonin transporter by escitalopram may result in greater activation of 5-HT1A receptors and regulation of 5-HT1A receptor function at the level of receptor-G protein interaction, as
opposed to regulation of 5-HT1A receptor function distal to receptor-G protein interaction. It would be of interest to determine whether differences in the mechanism of somatodendritic
5-HT1A autoreceptor desensitization are related to antidepressant drug efficacy, therapeutic response or clinical outcome.
http://www.ncbi.nlm..../nihms43816.pdf
 
This one made me wonder:
Differential Regulation of 5-HT1A Receptor-G Protein Interactions in Brain Following Chronic Antidepressant Administration
Our data suggest that the capacity of the 5-HT1A receptor to activate G protein is reduced in serotonergic cell body areas following chronic fluoxetine administration. No significant change in postsynaptic 5-HT1A receptor-stimulated [35S]GTPgammaS binding was observed in any of the forebrain areas examined following chronic treatment with either antidepressant. Thus changes in postsynaptic 5-HT1A receptor-mediated responses reported to follow chronic SSRI or tricyclic antidepressant administration appear to occur more distal to receptor-G protein interaction, perhaps at the level of effector, or involving changes in neuronal function at the system or circuit level.
http://www.nature.co...l/1395838a.html
 
I didnt had the time to read & comprehend it but why are they talking so much about the post 5-ht1a, if no changes in the g-proteins (or any other) were proved ?
Could it be that the pre 5-ht1a receptors in the Raphe dont have such a great impact but theres a synergy with the post 5-ht1a ?
 
Acute and chronic effects of citalopram on 5-HT1A receptor—Labeling by [18F]MPPF and—Coupling to receptors-G proteins
 
Chronic citalopram did not modify 5-HT1A receptor density in any of the brain regions studied. In addition, this treatment did not modify 8-OH-DPAT-stimulated [35S]-GTPγS binding in DR, although a significant increase was observed in frontal cortex and hippocampus. [18F]MPPF appears to be an efficient radioligand to quantify specifically 5-HT1A receptor density in brain imaging. The delayed therapeutic efficacy of citalopram did not appear to be linked to either a downregulation of 5-HT1A receptors or to a 5-HT1A receptor-G protein decoupling process in serotonergic neurons, but to increased functional sensitivity of postsynaptic 5-HT1A receptors.
http://onlinelibrary.../syn.20588/epdf
 
Anyway, How about to find ways to decrease the function of postsynaptic 5-ht1a or overexpress them like D2 receptors in Dyskinesia?
Because some people form the PSSD forum reported some very good improvements with Zinc
Admittely I believe the effect is due to 5-ht1a deactivation however it also activates SERT and some other things.
 
This could be a possible target i.e. the opposite of the sugessted lol so a pro-depressie state lol:
RGS inhibition at Gαi2 selectively potentiates 5-HT1A–mediated antidepressant effects
http://www.pnas.org/.../11086.full.pdf
 
therer are sparse informations about herbs and RGS interactions. The following might be promising at the first glance but PKC activation doesnt help because its afaik frequently activated.
but might maybe explain why Huperzine helps somewhat (?)
Anyway: 
 
Identification of Protein Kinase C Activation as a Novel Mechanism for RGS2 Protein Upregulation through Phenotypic Screening of Natural Product Extracts
Indolactam V, a known protein kinase C (PKC) activator, which selectively increased RGS2 protein levels in a time- and concentration-dependent manner. Similar results were obtained with phorbol 12-myristate 13-acetate as well as activation of the Gq-coupled muscarinic M3 receptor. The effect on RGS2 protein levels was blocked by the nonselective PKC inhibitor Gö6983
http://molpharm.aspe.../86/4/406.short
 
and heres something about RGS4 btw
 
Recent Updates in the Treatment of Neurodegenerative Disorders Using Natural Compounds
From the Indian medication, three plants (Rauvolfia serpentina, Withania somnifera, and Mandukparni) were selected for the investigation of their role in the management of schizophrenia by using the tools of bioinformatics. The active molecules from these plants were docked with RGS-4 protein (regulator for G protein signaling-4) considered to be responsible for schizophrenia. The docking of RGS-4 protein with the combinations of reserpine, withanolide, and asiaticoside from Rauvolfia serpentina, Withania somnifera, and Mandukparni, respectively, showed that such combination therapy could be helpful in the management of schizophrenia [8].
http://www.hindawi.c...am/2014/979730/
 
RGS6 is also interresting for Dopamine transmission or cell protection in parkinson
 
Sidenote: this is why I want to learn more about g-proteins
 
Regulators of G-protein-coupled receptor–G-protein coupling: antidepressants mechanism of action
Our knowledge concerning the basic mechanisms underlying the phenomenon of desensitization, internalization, downregulation and resensitization of the G-protein-coupled receptor has been advanced during the last decade. The present review discusses the possible involvement of regulators of G-protein-coupled receptor-G-protein coupling: beta-arrestins, G-protein-coupled receptor kinases and phosducin-like proteins, as well as beta-arrestins alternative signaling events, in the pathophysiology, diagnosis and treatment monitoring of mood disorders and in the mechanism of action of antidepressant medications.
Regulators of G-protein-coupled receptor-G-protein coupling: Antidepressants mechanism of action - ResearchGate. Available from: http://www.researchg...anism_of_action [accessed Oct 12, 2015].
http://www.researchg...anism_of_action
 
lol this is not a text wall but almost a book
					
					
					
							Edited by Flex, 11 October 2015 - 11:50 PM.