DIFFERENTIAL-EFFECTS OF CHRONIC ANTIDEPRESSANT TREATMENT ON 5-HT1C RECEPTOR-BINDING SITES IN WISTAR RAT-BRAIN

The effects of chronic clomipramine, imipramine and clorgyline on 5-HT 1C receptors were studied in discrete brain regions, in male Wistar ra ts, using [H-3]mesulergine to label the receptor binding sites. Clorgy line treatment significantly reduced [H-3]mesulergine binding (B-max v alues) in both the hypothalamus and striatum compared to saline-treate d animals. There were no differences in the maximum number of [H-3]mes ulergine binding sites following clorgyline in the hippocampus, fronta l cortex or brainstem. Neither clomipramine or imipramine treatment re sulted in any significant changes in 5-HT1C receptor number in the bra in regions examined here. Furthermore, the K-d Values (receptor affini ty) for [H-3]mesulergine binding were not significantly different comp aring treatment groups to control animals. The significant changes in discrete brain regions following chlorgyline treatment suggest that 5- HT1C receptors may be involved in the clinical efficacy for the treatm ent of depression and other neuropsychiatric disorders.