Effects of central 5,7-dihydroxytryptamine on the medical hypothalamic syndrome in rats

The present study attempted to replicate and extend two recent studies that implicated aberrant brain 5-HT neurotransmission in the etiology of overeating and BW grain. Adult female rats received 25 mg/kg of desipramine hydrochloride 30--45 min prior to an intracisternal injection of 200 microgram (free base) of 5,7-DHT creatinine sulfate or its 1% ascorbic acid aqueous vehicle. After 7 weeks of measuring food intake, water intake, and BW change, rats from both groups received radiofrequency lesions of the MH or sham surgery. After 5 additional weeks of intake and BW measurements, all rats were tested for 24-hr acceptance of varying sucrose and quinine solutions and for 25-day acceptance of a high-fat replacement diet. While 5,7-DHT depleted brain 5-HT by 45%, it did not induce overeating and BW gain alone nor did it modify the overeating, obesity, or "finickiness" produced by hypothalamic injury. Several factors that relate to specificity, sufficiency, and compatibility with other 5-HT depletory techniques were discussed, as were factors of similarity and dissimilarity between this and the previous experiments that we attempted to replicate.