Posted by SLS on March 12, 2002, at 9:56:11
In reply to Re: High Dose Prozac, posted by Psydoc on March 7, 2002, at 4:46:24
Oops.
Sorry, doctor.
After rereading the abstract, I see that it is not 5-HT2 receptor antagonism that was concluded to occur, but rather, receptor downregulation.
What do you make of this?
- Scott
> ---------------------------------------------
>
> 168: J Neural Transm Suppl 1994;41:127-34
>
> Comparisons of the actions of high and low doses of the MAO
> inhibitor tranylcypromine on 5-HT2 binding sites in rat cortex.
>
> Goodnough DB, Baker GB
>
> Department of Psychiatry, University of Alberta, Edmonton, Canada.
>
> Tranylcypromine (TCP) is a commercially available antidepressant
> drug, and recent literature reports suggest that high doses of this
> drug may be particularly effective in treating refractory
> depression. Down-regulation of 5-HT2 receptors in rat cortex is an
> effect produced after chronic administration of several
> antidepressants, and we have conducted a chronic study comparing
> low- and high-dose TCP in this regard. Male Sprague-Dawley rats
> were administered TCP (0.5 or 2.5 mg/kg/day) or vehicle (distilled
> water) via Alzet minipumps implanted subcutaneously in the dorsal
> thoracic area. Groups of rats were killed 4, 10 or 28 days after
> pump implantation and whole cortex was dissected out and utilized
> for preparation of a membrane fraction. Binding studies were
> performed with this fraction using 3H- ketanserin as the
> radioligand. Down-regulation (decrease in Bmax) of the 5-HT2
> binding site was observed in high-dose animals after 10 and 28 days
> but not after 4 days. Low-dose TCP had no effect on 5-HT2 densities
> at any time interval. The affinity of 3H-ketanserin for the 5-HT2
> site was not affected by either dose at any time interval. These
> results suggest that down-regulation of the 5-HT2 site may
> contribute to the efficacy of high-dose TCP in the treatment of
> refractory depression.
>
> PMID: 7931218, UI: 95016589
poster:SLS
thread:27771
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