Posted by ed_uk on August 15, 2005, at 6:22:25
In reply to Re: Citalopram vs escitalopram, posted by ed_uk on August 15, 2005, at 6:19:35
Hmmm, I can't believe I'm saying this but I'm actually thinking of trying escitalopram instead of citalopram!! I might try 20mg escitalopram istead of 60mg citalopram.
Neuropsychopharmacology. 2005 Jul;30(7):1269-77.
Effects of acute and long-term administration of escitalopram and citalopram on serotonin neurotransmission: an in vivo electrophysiological study in rat brain.
El Mansari M, Sanchez C, Chouvet G, Renaud B, Haddjeri N.
Laboratory of Neuropharmacology and Neurochemistry, Faculty of Pharmacy, University of Claude Bernard Lyon I, Lyon Cedex, France.
The present study was undertaken to compare the acute and long-term effects of escitalopram and citalopram on rat brain 5-HT neurotransmission, using electrophysiological techniques. In hippocampus, after 2 weeks of treatment with escitalopram (10 mg/kg/day, s.c.) or citalopram (20 mg/kg/day, s.c.), the administration of the selective 5-HT(1A) receptor antagonist WAY-100,635 (20-100 microg/kg, i.v.) dose-dependently induced a similar increase in the firing activity of dorsal hippocampus CA(3) pyramidal neurons, thus revealing direct functional evidence of an enhanced tonic activation of postsynaptic 5-HT(1A) receptors. In dorsal raphe nucleus, escitalopram was four times more potent than citalopram in suppressing the firing activity of presumed 5-HT neurons (ED(50)=58 and 254 mug/kg, i.v., respectively). Interestingly, the suppressant effect of escitalopram (100 microg/kg, i.v.) was significantly prevented, but not reversed by R-citalopram (250 microg/kg, i.v.). Sustained administration of escitalopram and citalopram significantly decreased the spontaneous firing activity of presumed 5-HT neurons. This firing activity returned to control rate after 2 weeks in rats treated with escitalopram, but only after 3 weeks using citalopram, and was associated with a desensitization of somatodendritic 5-HT(1A) autoreceptors. These results suggest that the time course of the gradual return of presumed 5-HT neuronal firing activity, which was reported to account for the delayed effect of SSRI on 5-HT transmission, is congruent with the earlier onset of action of escitalopram vs citalopram in validated animal models of depression and anxiety.