L-Dopa feeding suppression: effect on catecholamine neurons of the perifornical lateral hypothalamus.
Injection of L-Dopa (0.8--200 nmoles) into the perifornical hypothalamus produced a dose-dependent suppression of feeding in hungry rats. This effect was positively correlated in magnitude with the same effect produced by the catecholamine agonists dopamine and epinephrine, and by the catecholamine-releasing drug amphetamine. L-Dopa's action was partially antagonized by separate injections of the dopaminergic blocker haloperidol (58% blockade) and the beta-adrenergic blocker propranolol (38% blockade). Combined injections of these two antagonists produced a 90% blockade of L-Dopa's effect. Perifornical administration of the dopa decarboxylase inhibitors Ro 4-4602 and MK-486 was also shown to reverse L-Dopas feeding suppression, at doses that enhanced the effect of injected dopamine and epinephrine. On the basis of these findings, L-Dopa appears to suppress food consumption in part through increased catecholamine synthesis, specifically within dopaminergic and adrenergic neurons of the perifornical hypothalamic region.
D000818:Animals; D002395:Catecholamines / Q000494:pharmacology / Q000502:physiology*; D003864:Depression, Chemical; D003913:Dextroamphetamine / Q000494:pharmacology; D004347:Drug Interactions; D005247:Feeding Behavior / Q000187:drug effects*; D007031:Hypothalamus / Q000187:drug effects*; D007980:Levodopa / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000187:drug effects*; D010293:Pargyline / Q000494:pharmacology; D051381:Rats
D002395:Catecholamines; D007980:Levodopa; D010293:Pargyline; D003913:Dextroamphetamine