l-Dopa feeding suppression: Effect on catecholamine neurons of the perifornical lateral hypothalamus

✍ Scribed by S. F. Leibowitz; C. Rossakis

• Publisher: Springer
• Year: 1979
• Tongue: English
• Weight: 866 KB
• Volume: 61
• Category: Article
• ISSN: 0033-3158
• DOI: 10.1007/bf00432272

✦ Synopsis

Injection of L-Dopa (0.8--200 nmoles) into the perifornical hypothalamus produced a dosedependent 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 catecholaminereleasing drug amphetamine. L-Dopa's action was partially antagonized by separate injections of the dopaminergic blocker haloperidol (58 ~o blockade) and the/3-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-Dopa's 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.