Posted by psychobot5000 on January 26, 2007, at 13:45:35
In reply to Re: Can anyone have a 'Normal' life on Parnate?, posted by corafree on January 26, 2007, at 12:49:17
I've puzzled over that, too. I think that what it says is that desipramine and fluoxetine both 'sensitize' D2 receptors in those areas of the brain, meaning I suppose that they somehow indirectly get the brain to be more sensitive to dopamine at those receptors.
Tranylcypromine, however, does something different (though it would act on the same systems). It directly increases dopamine concentrations. This isn't surprising, since Tranylcypromine seems to have several mechanisms that (stimulant-like) increase dopamine directly. Because of the extra dopamine bouncing around, some of the receptors (according to the study) actually downregulate in response to the Parnate (those in the striatum).
That's how I read it.
> http://www.biopsychiatry.com/dopamine.htm
>
> Antidepressants and the dopamine connection
>
> Measurement of D2-like binding by receptor autoradiography, using the ligand [3H]YM-09151-2, revealed that both fluoxetine and desipramine increased D2-like binding in the nucleus accumbens shell; fluoxetine had a similar effect in the nucleus accumbens core. Tranylcypromine, however, had no effect on D2-like binding in the nucleus accumbens but decreased binding in the striatum. In micro-dialysis experiments, our data showed that levels of extracellular dopamine in the nucleus accumbens were not altered in rats treated with either fluoxetine or desipramine, but increased by tranylcypromine.
>
> What does this say??? :(
>
> tks, cf
poster:psychobot5000
thread:726465
URL: http://www.dr-bob.org/babble/20070125/msgs/726744.html