Increased precursor availability did not increase food intake and 5-HT turnover rate in the hypothalamus of diazepam injected rats.
In view of a possible role of serotonin (5-hydroxytryptamine; 5- HT) in regulation of appetite and anxiety, the effects of 1, 3 and 5 mg/kg doses of diazepam on brain serotonin precursor and effects of single and repeated diazepam (1 mg/kg 2* daily for 4 days) administration on hypothalamic 5-HT, 5-hydroxyindoleacetic acid (5-HIAA and 5-HIAA/5-HT ratio are investigated in rats. Daily diazepam treatment decreased food intakes. Diazepam injected rats exhibited a dose-dependent increase of tryptophan in the hypothalamus. Administration of diazepam (1 mg/kg) to 4 day saline injected rats on the 5th day increased 5-HT and decreased 5-HIAA levels in the hypothalamus. 5-HIAA/5-HT level also decreased. 4-day diazepam injected rats injected with saline on the 5th day also exhibited similar changes of 5-HT. 5-HIAA and 5-HIAA/5-HT ratio. Administration of diazepam to 4 day diazepam injected rats again decreased 5-HIAA concentrations but did not increase 5-HT levels in the hypothalami of rats. Possible mechanism involved in the anorectic effects of diazepam-induced changes of hypothalamic 5-HT turnover rate is discussed.
Batool
F
F
Department of Biochemistry, University of Karachi, Karachi-75270, Pakistan.
Haleem
D J
DJ