Effect of third ventricle administration of L-694,247, a selective 5-HT1(D) receptor agonist, on water intake in rats

Abstract

DE CASTRO-E-SILVA, E., C. SARMENTO, T. A. NASCIMENTO, C. P. LUZ, T. SOARES, C. A. MARINHO, M. CUNHA, C. BULCÃO, I. R. DE OLIVEIRA AND J. B. FREGONEZE. Effect of third ventricle administration of L-694,247, a selective 5-HT1D receptor agonist, on water intake in rats. PHARMACOL BIOCHEM BEHAV 57[4]749–754, 1997.—L-694,247, a selective 5-HT1D receptor agonist, injected directly into the third ventricle (2.5, 5.0, and 10.0 μg/rat) of dehydrated rats induced a dose-dependent partial blockade of water intake. Injected in this way, the compound abolishes drinking behavior induced by third ventricle administration of carbachol (2 μg/rat), angiotensin II (5 ng/rat), and isoproterenol (40 μg/rat). In addition, intraventricular injections of L-694,247 did not modify water intake in normohydrated rats. The effects of L-694,247 are due to a specific interaction with 5-HT1D receptors, because its inhibitory effect on water intake in dehydrated rats is blocked by the previous administration of a 5-HT1D antagonist, GR 127935 (5 μg/rat), directly into the third ventricle. It is concluded that central 5-HT1D receptor activation disrupts the functional integrity of central pathways related to drinking behavior.