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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 13 of 13. This is the beginning of the thread.
Posted by Sarah T. on February 24, 2005, at 0:51:45
I saw some old posts on this board about antidepressants that fall into the 5-HT2C receptor antagonist category. Does anyone know which AD's fall into this group? I know a few but I'd like to know all of them. If I remember correctly, these AD's are good for increasing serotonin without causing the decrease in dopamine that occurs with ssri's.
Posted by SLS on February 24, 2005, at 8:45:55
In reply to 5-HT2C receptor antagonists, posted by Sarah T. on February 24, 2005, at 0:51:45
> I saw some old posts on this board about antidepressants that fall into the 5-HT2C receptor antagonist category. Does anyone know which AD's fall into this group? I know a few but I'd like to know all of them. If I remember correctly, these AD's are good for increasing serotonin without causing the decrease in dopamine that occurs with ssri's.
Remeron was the first to come to mind. I think it would be helpful if your were to list those you already know of.
- Scott
Posted by Optimist on February 24, 2005, at 11:15:42
In reply to Re: 5-HT2C receptor antagonists, posted by SLS on February 24, 2005, at 8:45:55
My impression was that 5HT2a was the receptor responsible for reducing dopamine as well as causing insomnia, sexual dysfunction and agitation. Trazadone, Serzone, Buspar, Remeron, high dose Parnate, Periactin, Amantadine, and many of the antipsychotics block this receptor.
Blocking 5HT2c can result in weight gain which is why Remeron is so known to pack on the weight.
Brian
Posted by KaraS on February 24, 2005, at 14:43:29
In reply to Re: 5-HT2C receptor antagonists, posted by Optimist on February 24, 2005, at 11:15:42
> My impression was that as well as causing insomnia, sexual dysfunction and agitation. Trazadone, Serzone, Buspar, Remeron, high dose Parnate, Periactin, Amantadine, and many of the antipsychotics block this receptor.
>
> Blocking 5HT2c can result in weight gain which is why Remeron is so known to pack on the weight.
>
> Brian
How can it be that 5HT2a is the receptor responsible for reducing dopamine? I thought that the SSRIs known to produce apathy do so by eventually decreasing dopamine. Prozac and Effexor are famous for this and they both had that effect on me - yet you don't have them listed as blockers of 5HT2a.
Posted by linkadge on February 24, 2005, at 15:23:50
In reply to Re: 5-HT2C receptor antagonists » Optimist, posted by KaraS on February 24, 2005, at 14:43:29
Both 5-ht2a and 5-ht2c "agonism" causes reduced dopamine in the prefrontal cortex.
5-ht2a/c anatagonists can reduce this effect and increase prefrontal dopamine release.
5-ht2a agonism can cause anxiety and insomnia, and 5-ht2c agonism generally causes sexual dysfunction and decreased apetite.
However. Blocking the 5-ht2c receptor blocks the antidepressant effect of prozac. See the link...http://biopsychiatry.com/5ht2cantid.htm
So 5-ht2c antagonism might reduce the AD effect of a drug.
There is a lot over overlap between the 5-ht2a/c receptors and their clinical actions.
Linkadge
Posted by linkadge on February 24, 2005, at 15:25:17
In reply to Re: 5-HT2C receptor antagonists » Optimist, posted by KaraS on February 24, 2005, at 14:43:29
Oh, and BTW: Serzone is actually a 5-ht2a antagonist, but a 5-ht2c Agonist.
Weird.
Linkadge
Posted by KaraS on February 24, 2005, at 15:49:08
In reply to Re: 5-HT2C receptor antagonists, posted by linkadge on February 24, 2005, at 15:23:50
> Both 5-ht2a and 5-ht2c "agonism" causes reduced dopamine in the prefrontal cortex.
>
> 5-ht2a/c anatagonists can reduce this effect and increase prefrontal dopamine release.
>
> 5-ht2a agonism can cause anxiety and insomnia, and 5-ht2c agonism generally causes sexual dysfunction and decreased apetite.
>
>
> However. Blocking the 5-ht2c receptor blocks the antidepressant effect of prozac. See the link...
>
> http://biopsychiatry.com/5ht2cantid.htm
>
> So 5-ht2c antagonism might reduce the AD effect of a drug.
>
> There is a lot over overlap between the 5-ht2a/c receptors and their clinical actions.
>
>
> Linkadge
Thanks. You're so freakin' smart!!!K
Posted by KaraS on February 24, 2005, at 15:57:22
In reply to Re: 5-HT2C receptor antagonists, posted by linkadge on February 24, 2005, at 15:23:50
> Both 5-ht2a and 5-ht2c "agonism" causes reduced dopamine in the prefrontal cortex.
>
> 5-ht2a/c anatagonists can reduce this effect and increase prefrontal dopamine release.
>
> 5-ht2a agonism can cause anxiety and insomnia, and 5-ht2c agonism generally causes sexual dysfunction and decreased apetite.
>
>
> However. Blocking the 5-ht2c receptor blocks the antidepressant effect of prozac. See the link...
>
> http://biopsychiatry.com/5ht2cantid.htm
>
> So 5-ht2c antagonism might reduce the AD effect of a drug.
>
> There is a lot over overlap between the 5-ht2a/c receptors and their clinical actions.
>
>
> Linkadge
>But wait, Prozac is a 5ht2c antagonist and it depresses dopamine overall. Is this because of the strong 5-ht reuptake inhibition?
k
Posted by banga on February 24, 2005, at 17:36:26
In reply to Re: 5-HT2C receptor antagonists, posted by linkadge on February 24, 2005, at 15:23:50
> 5-ht2a/c anatagonists can reduce this effect and increase prefrontal dopamine release.>
AHA! That is what my pdoc was referring to this morning...he stated that the Abilify causes dopamine release, and before I could ask about it, we were on another topic...so the 5ht2a antagonism is what increases dopamine...(I had just asked about this in the thread below "adderall + strattera=anxiety relief...")But isnt that curious?, as other atypical antipsychotics also are potent 5ht2a antagonists..thus on the one hand they lead to dopamine release, yet on the other potently block certain dopamine sites.....
Posted by Optimist on February 24, 2005, at 23:04:36
In reply to Re: 5-HT2C receptor antagonists, posted by banga on February 24, 2005, at 17:36:26
>
> > 5-ht2a/c anatagonists can reduce this effect and increase prefrontal dopamine release.
>
> >
> AHA! That is what my pdoc was referring to this morning...he stated that the Abilify causes dopamine release, and before I could ask about it, we were on another topic...so the 5ht2a antagonism is what increases dopamine...(I had just asked about this in the thread below "adderall + strattera=anxiety relief...")
>
> But isnt that curious?, as other atypical antipsychotics also are potent 5ht2a antagonists..thus on the one hand they lead to dopamine release, yet on the other potently block certain dopamine sites.....Yeah, the D2 antagonism helps with the positive symptoms of schizophrenia whereas the 5HT2a antagonism helps with the negative symptoms. That's why the atypical AP's are so much better in that regard. The older AP's only mostly helped the positive symptoms.
Brian
Posted by banga on February 25, 2005, at 0:39:59
In reply to Re: 5-HT2C receptor antagonists » banga, posted by Optimist on February 24, 2005, at 23:04:36
You are right...I knew that atypicals are better for the positive symptoms...but as I became interested in antianxiety properties, I lost focus on noting what may be the mechanism for the relief of negative symptoms.... Huh. Interesting about the dopamine. Since 5ht2a antagonism seems key for me in lessening at least some aspects of anxiety.
Posted by linkadge on February 25, 2005, at 15:50:58
In reply to Re: 5-HT2C receptor antagonists, posted by banga on February 25, 2005, at 0:39:59
It's kind of a mixed bag. I read in a few places that there was a little paradox. Atypicals increase dopamine release in the frontal cortex via 5-ht2a angatonism, yet most of them bind fairly strongly to d2 receptors in the frontal cortex which can lead to some negation of their effect.
Yes, prozac dirtier than the other SSRI's. One of its interesting effects is that it acts as a 5-ht2c antagonist. Prozac leads to more dopamine in the frontal cortex than the other SSRI's.But, I would imagine that by taking prozac there would be an overall *agonism* at the 5-ht2c receptors. Ie it would only block a *certain portion* of the serotonin that it increases.
So I would imagine that this article is talking about blocking futher blocking the 5-ht2c receptor which seems to block the AD effect of the drug.
Linkadge
Posted by Sarah T. on February 28, 2005, at 23:54:45
In reply to Re: 5-HT2C receptor antagonists, posted by linkadge on February 25, 2005, at 15:50:58
Hi Linkage. Is Prozac the only ssri that functions as a 5-HT2C antagonist (or partial 5HT2C antagonist)? Do you think that the agonism negates the antagonism in Prozac?
This is the end of the thread.
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