D-Fenfluramine, an anorectic that releases serotonin (5-HT), repeatedly injected in rats (15 mg/kg per day) enhanced the met5-enkephalin and β-endorphin content of the hypothalamus. The onset of this effect was slow, reaching a peak at 5 days; the increase in β-endorphin gradually declined toward control level while the drug was still being administered although that of met-enkephalin persisted for 15 days. The elevation of the opioid peptide content of the hypothalamus was temporally associated with a slowing in the rate of body weight increase. A transient, small, increase in striatal met-enkephalin content was also induced by repeated D-fenfluramine injections: however the metenkephalin content of frontal cortex, hippocampus and brainstem was not affected. A modification of the β-endorphin content of hypothalamus was not seen after acute injection of D-fenfluramine or D-amphetamine but an increase was observed during repeated treatment with D-fenfluramine. Repeated injections of D-amphetamine for 5 days (4.5 mg/kg per day) failed to increase either the met-enkephalin or the β-endophin content of the hypothalamus. These data suggest that the anorexia elicited by repeated injections of D-fenfluramine but not that elicited by D-amphetamine, includes a participation by hypothalamic and β-endosphin stores.
- anorectic drugs
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience