Posted by iris2 on July 10, 2004, at 22:36:01
In reply to Re: another question on gepirone » noa, posted by SLS on February 9, 2003, at 9:53:29
> > In re: gepirone (Ariza)
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> Gepirone is a serotonergic drug being developed by Organon. It is tentatively scheduled to be approved in 2004 as an extended-release preparation. Gepirone binds tightly to the serotonin receptor, 5-HT1a, without affecting dopamine D2 receptors. JRBecker explained this very well.
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> http://www.dr-bob.org/babble/20030208/msgs/140184.html
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> Gepirone is a full agonist of the 5-HT1a presynaptic autoreceptor. The stimulation of these receptors actually reduces the synthesis and release of serotonin, reducing neuronal activity. It also binds to postsynaptic 5-HT1a receptors, an action that tends to increase neuronal activity. Although bound to a receptor, it does not necessarily stimulate it. It is thus called a "partial agonist" at this site. Not only do 5-HT1a receptors exist on serotonergic neurons, they are also found on dopaminergic neurons. The stimulation of these receptors can increase the release of dopamine from these neurons.
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> * partial agonist: a drug with lower intrinsic activity than a full agonist, producing a lower maximum effect.
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> So, what is the net effect of gepirone on serotoninergic activity? I'm not sure. It appears to me that it might act as a sort of a synaptic stabilizer, moderating serotonergic tone to prevent hyperexcitability of neurons. There are several other sites along the neuron that 5-HT1a receptors are located. They appear on the axon (the "transmission cable") and the soma (cell body containing the nucleus and control machinery). I'm pretty sure that these receptors act as autoreceptors to regulate and decrease serotonergic activity. This is probably the mechanism by which it is reported by some that pindolol accelerates the antidepressant response to SSRIs (although not increasing the percentage of people who respond). Pindolol is probably acting as a temporary dampener of neuronal excitability until postsynaptic receptors are downregulated. That's my guess, anyway. I guess I should study this stuff more closely. I don't find myself with the energy nor motivation to research things so much anymore. I'd rather be married with children.
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> Oh well...
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> - Scott
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> Scott,You made my day!
"I'd rather be married with children." Let's research that one for a while. It would most likely be more informative and might actually yield measurable results!
iris
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poster:iris2
thread:139984
URL: http://www.dr-bob.org/babble/20040710/msgs/364867.html