Posted by King Vultan on August 23, 2004, at 12:52:36
In reply to Re: Nardil Observations » King Vultan, posted by Sad Panda on August 23, 2004, at 6:17:01
> Hi Todd,
>
> Nice report, just one question:
>
> Since both MAO-A & MAO-B metabolize dopamine, while serotonin & norepinephrine are only metabolized by MAO-A, wouldn't that mean that Nardil, Marplan & Parnate all raise dopamine levels more than serotonin & norepinephrine levels?
>
> Cheers,
> Panda.
>I don't think this is a conclusion that can necessarily be reached without doing some lab studies. While it is true that MAO-A also metabolizes dopamine, some studies have indicated that selective MAO-A inhibitors have no effect on the concentration of DOPAC, a key dopamine metabolite, whereas MAO-B inhibitors and nonselective MAOIs reduce DOPAC concentrations. The implication is that the latter two types decrease the consumption of dopamine by MAO, causing the amount of resultant dopamine metabolites to fall accordingly. Specifically, it would seem to be MAO-B that is involved, as this is the only type of MAO common to both nonselective MAOIs and MAO-B inhibitors.
Beyond the MAO inhibition issues, it's clear that Parnate raises dopamine levels more than either Nardil or Marplan, judging from Parnate's relative lack of sexual side effects compared to the other two drugs. However, this has nothing to do with MAO inhibition, but rather, Parnate's amphetamine-like structure and stimulant-type effects. As for Nardil, I was frankly a little surprised as to the poor libido and sexual side effects I observed while on it, as I would have thought its MAO-B (and MAO-A) inhibition would have liberated enough dopamine to negate these effects. Such was not the case, though, at least for me.
Todd
poster:King Vultan
thread:381095
URL: http://www.dr-bob.org/babble/20040821/msgs/381292.html