Ventromedial hypothalamus vs. lateral hypothalamic D2 satiety receptors in the body weight increase induced by systemic sulpiride.
Two experiments were conducted in order to see if dopamine satiety receptors in the lateral hypothalamus or satiety mechanisms in the ventromedial hypothalamus were involved in the hyperphagia and body weight increase induced by systemic sulpiride. In the first experiment, it was shown that systemic sulpiride (20 mg/kg) does not block the anorexia caused by intraperifornical injections of amphetamine. In the second experiment, sulpiride (20 mg/kg during 18 days) did not produce an additional increase in body weight in previously VMH-lesioned female rats. This last fact cannot be explained by a ceiling effect since insulin (5 U/day during 7 days) increased body weight in the same VMH rats in which sulpiride was not effective. These results do not support the hypothesis that systemic sulpiride reaches the perifornical dopamine D2 receptors to disinhibit feeding, but suggest instead an involvement of the ventromedial hypothalamus. This last suggestion is more in agreement with the hypothesis that sulpiride alters feeding and body weight gain through the induction of a functional gonadectomy.
Parada
M A
MA
Laboratorio de Fisiología de la Conducta, Facultad de Medicina Universidad de Los Andes, Mérida, Venezuela.
Puig de Parada
M
M
Hernandez
L
L
Murzi
E
E
D000661:Amphetamine / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D004435:Eating / Q000187:drug effects; D005260:Female; D007026:Hypothalamic Area, Lateral / Q000033:anatomy & histology / Q000502:physiology*; D007267:Injections; D007274:Injections, Intraperitoneal; D007328:Insulin / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects; D017448:Receptors, Dopamine D2; D012528:Satiety Response / Q000187:drug effects / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000502:physiology*; D013469:Sulpiride / Q000008:administration & dosage / Q000494:pharmacology*; D014697:Ventromedial Hypothalamic Nucleus / Q000033:anatomy & histology / Q000502:physiology*; D015430:Weight Gain / Q000187:drug effects / Q000502:physiology*
D007328:Insulin; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D013469:Sulpiride; D000661:Amphetamine