Sulpiride injections in the lateral hypothalamus induce feeding and drinking in rats.
Amphetamine injections into the lateral hypothalamus inhibit feeding. This effect is blocked by local administration of neuroleptics, suggesting a role for dopamine in feeding inhibition. However, the type of dopamine receptor involved in satiety is not known. Therefore, we tested the effect of intrahypothalamic injections of sulpiride, a specific D2 receptor blocker, on amphetamine anorexia in food-deprived rats, and on spontaneous feeding and drinking in satiated rats. Sulpiride attenuated by 36% the anorexia produced by intrahypothalamic injections of amphetamine. In satiated rats, sulpiride (8 micrograms/0.5 microliter) elicited feeding (mean food intake after sulpiride: 5.4 g, and after vehicle 1.6 g, p less than 0.001), and drinking (mean water intake after sulpiride: 12.3 ml, and after vehicle: 0.9 ml, p less than 0.001). A dose response relationship was found between sulpiride dose and feeding or drinking. Sulpiride-induced drinking was observed in the absence of food, showing that it is not a postprandial phenomenon. These results suggest that hypothalamic D2 receptors might be involved in feeding and drinking regulation.
Parada
M A
MA
Laboratorio de Fisiologia de la Conducta, Universidad de los Andes, Merida, Venezuela.
Hernandez
L
L
Hoebel
B G
BG
D000818:Animals; D000855:Anorexia / Q000503:physiopathology; D003913:Dextroamphetamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects*; D007026:Hypothalamic Area, Lateral / Q000187:drug effects / Q000502:physiology*; D007267:Injections; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013469:Sulpiride / Q000008:administration & dosage / Q000494:pharmacology*
D013469:Sulpiride; D003913:Dextroamphetamine