Jpn. J. Pharmacol. 78 (4), 515-517 (1998)

Enhancement of Serotonin 2C Receptor mRNA Expression by Antidepressants Possessing the Receptor-Blocking Activity in the Rat Brain

Michihisa Tohda and Hiroshi Watanabe

Department of Pharmacology, Research Institute for Wakan-yaku, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan

Abstract: The effects of repeated oral administration of antidepressants on the serotonin 2C receptor subtype (5-HT2CR) mRNA level in the rat brain were examined. Imipramine (20 mg/kg, p.o.) enhanced the hybridization signal in a time (days)-dependent manner, reaching a maximum at day 4 and maintaining a high level until day 14. Desipramine and mianserin, which have 5-HT2CR antagonistic activity, also stimulated the mRNA expression to about same extents as imipramine, but nomifensine, which has no effect on 5-HT2CR, was ineffective. These results suggest that long-term treatment with antidepressants, which act as 5-HT2CR antagonists, stimulates 5-HT2CR mRNA expression.

Keywords: Serotonin 2C receptor, Antidepressant, mRNA expression

Copyrightę The Japanese Pharmacological Society 1998

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