INCREASED PRECURSOR AVAILABILITY DID NOT INCREASE FOOD INTAKE AND 5-HT TURNOVER RATE IN THE HYPOTHALAMUS OF DIAZEPAM INJECTED RATS

Abstract

In view of a possible role of serotonin (5-hydroxytryplamine 5-HT) in regulation of appetite and anxiety, the effects of 1,3 and 5mg/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. Diazepain 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 in-creased 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 ex hibited 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 in-crease 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.