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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 8 of 8. This is the beginning of the thread.
Posted by Questionmark on June 10, 2004, at 21:17:55
i have read a number of articles and posts, here, about which receptor is responsible for sexual side effects and anorgasmia in particular: 5-HT2A or 5-HT2C receptors. But i canNOT find a definitive answer! Some say it is the former and some say it is the latter. Maybe it is both, i don't know. But i wish i could verify this for sure. If anyone can help find a verifiable answer/conclusion to this i would be grateful and impressed. Thanks.
Posted by King Vultan on June 11, 2004, at 7:52:19
In reply to 5-HT2A vs. 5-HT2C, posted by Questionmark on June 10, 2004, at 21:17:55
> i have read a number of articles and posts, here, about which receptor is responsible for sexual side effects and anorgasmia in particular: 5-HT2A or 5-HT2C receptors. But i canNOT find a definitive answer! Some say it is the former and some say it is the latter. Maybe it is both, i don't know. But i wish i could verify this for sure. If anyone can help find a verifiable answer/conclusion to this i would be grateful and impressed. Thanks.
Stahl in "Essential Psychopharmacology" says it's the 5-HT2A receptors. Unfortunately, I don't have the book with me today at work, and I can't remember exactly what he says about the 5-HT2C receptors. I will try to remember to look it up when I get home.Todd
Posted by linkadge on June 11, 2004, at 9:49:37
In reply to Re: 5-HT2A vs. 5-HT2C » Questionmark, posted by King Vultan on June 11, 2004, at 7:52:19
I think it's the 2c receptors, the 2a receptors are involved in sleep.
look in www.biopsychiatry.com/refs under mirtazapine-sexual function, it seems to think the 2c receptors are the main culprit.
Linkadge
Posted by Sad Panda on June 11, 2004, at 10:49:08
In reply to 5-HT2A vs. 5-HT2C, posted by Questionmark on June 10, 2004, at 21:17:55
I only guess it's 5-HT2C because I haven't heard of too many cases of anorgasmia cured by taking TCA's. I don't think it really matters as it seems like a good idea to block both. One thing is certain, 5-HT2A blockade produces more deep sleep & is an antidote to serotonin syndrome.
Cheers,
Panda.
Posted by King Vultan on June 11, 2004, at 19:08:54
In reply to Re: 5-HT2A vs. 5-HT2C » Questionmark, posted by King Vultan on June 11, 2004, at 7:52:19
> Stahl in "Essential Psychopharmacology" says it's the 5-HT2A receptors. Unfortunately, I don't have the book with me today at work, and I can't remember exactly what he says about the 5-HT2C receptors. I will try to remember to look it up when I get home.
>
He says stimulating these receptors has these side effects:
2A (limbic cortex) agitation, anxiety, panic2A (spinal cord) orgasm dysfunction
2A (brain pleasure centers) loss of libido, apathy
2A (brainstem sleep centers) sleep disturbance, myoclonus
2A (basal ganglia) changes in motor movements, restlessness
2C (limbic cortex) agitation, anxiety, panic
2C (location not specified) reduced appetite
3 (hypothalamus) nausea
3 (brainstem) vomiting
3 & 4 (gastrointestinal tract) increased bowel motility, cramps, diarrhea
Todd
Posted by Sad Panda on June 12, 2004, at 3:26:49
In reply to Re: 5-HT2A vs. 5-HT2C followup, posted by King Vultan on June 11, 2004, at 19:08:54
>
> > Stahl in "Essential Psychopharmacology" says it's the 5-HT2A receptors. Unfortunately, I don't have the book with me today at work, and I can't remember exactly what he says about the 5-HT2C receptors. I will try to remember to look it up when I get home.
> >
>
>
> He says stimulating these receptors has these side effects:
>
>
> 2A (limbic cortex) agitation, anxiety, panic
>
> 2A (spinal cord) orgasm dysfunction
>
> 2A (brain pleasure centers) loss of libido, apathy
>
> 2A (brainstem sleep centers) sleep disturbance, myoclonus
>
> 2A (basal ganglia) changes in motor movements, restlessness
>
> 2C (limbic cortex) agitation, anxiety, panic
>
> 2C (location not specified) reduced appetite
>
> 3 (hypothalamus) nausea
>
> 3 (brainstem) vomiting
>
> 3 & 4 (gastrointestinal tract) increased bowel motility, cramps, diarrhea
>
>
> Todd
>
>Hard to argue against Stahl. :)
> 2C (location not specified) reduced appetite
Not hard to imagine why Remeron makes people fat, H1 & 5-HT2C antagonism both make people hungry. Remeron reduces my appetite, the happier I am, the less binge eating I do.
Cheers,
Panda.
Posted by Questionmark on June 12, 2004, at 5:25:47
In reply to Re: 5-HT2A vs. 5-HT2C followup, posted by King Vultan on June 11, 2004, at 19:08:54
Thank you Todd for the informative listing from that book by Stahl. i'm dissapointed, though, because it's incomplete. It didn't mention anything about 5-HT2C receptors being involved in sexual functioning, and they are almost certainly at least invOLved.
Linkadge, you made a good point about 5-HT2C receptors being involved in sexual function, but i disagree that 5-HT2A receptors are not involved as well. i have read more research indicating an involvement of the 5-HT2A receptors than the 5-HT2C receptors.
i'm still confused, but i am convinced that both receptor types are integrally involved, and stimulation of either often seems to have the same effects, in regard to sexual function. For instance, it seems that both receptor subtypes are involved in the inhibition of dopamine release in the brain's reward/pleasure centers (e.g., the nucleus accumbens). This means that stimulation of either receptor will lead to decreased libido and decreased reward & pleasure from sexual things, and eventually will precipitate delayed orgasm or anorgasmia as dopamine transmission continues to be lower. These receptors i think probably also have additional or differently-mediated effects on sexual response in other areas of the brain. And i am quite convinced that stimulation of 5-HT2A receptors in the spinal cord results in a decreased ability to have an orgasm & to ejaculate. Whether or not 5-HT2C receptors are involved in this (spinal inhibition) as well, i do not know. i'm curious.
Basically, i'm convinced that both receptor subtypes are generally related in their actions. i still wish i knew how they differed and in what ways (5-HT2C involvement in appetite is one probable example).
i so wish there was a selective 5-HT2A and/or 5-HT2C antagonist on the market. That would be great. Actually, why isn't there?! Imagine all the money it would make from the numerous people who have insomnia, anxiety, and especially sexual dysfunction from a serotonergic antidepressant! i don't understand why drug companies aren't racing to make a drug like this.
Anyway, i'm done rambling. Thanks your responses.
Posted by SLS on June 12, 2004, at 7:54:46
In reply to Re: 5-HT2A vs. 5-HT2C followup, posted by Questionmark on June 12, 2004, at 5:25:47
Serotonin receptors are friggin' complicated.
- Scott
This is the end of the thread.
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