Neurochemical Profile of 8-Hydroxy-2-(Di-N-propylamino) tetralin (8-OH-DPAT) Induced Hyperphagia in Sugar Rich Diet Treated Rats

To assess the role of hyperphagic serotonin-1A (5-hydroxytryptamine, 5-HT) receptors, if any, in the precipitation of hyperphagia associated with long term consumption of sugar rich diet, the present study is designed to investigate hyperphagic and brain serotonin metabolism attenuating effects of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), a 5-HT-1A selective agonist, following long term consumption of sugar as part of meal in rats. Sugar-rich diet was prepared by mixing standard rodent diet and table sugar in the ratio of 3:1(w/ w) and rats were fed freely on this diet for five weeks. Control rats were fed freely on standard rodent diet. Five-week food intakes were greater in sugar-rich-diet-treated than normal diet treated rats. After five weeks of treatment control and sugar-diet-treated animals were injected with 8-OH-DPAT at a dose of 0.5 mg/ ml/ kg. 8-OH-DPAT induced hyperphagia and decreases in serotonin metabolism were smaller in sugar-diet than normal-diet-treated rats. The results suggest that decrease in the responsiveness of somato-dendritic 5-HT-1A receptors is not involved in sugar-rich-diet-induced hyperphagia.