Roles for CCK 1 and 5-HT 3 receptors in the effects of CCK on presympathetic vasomotor neuronal discharge in the rat

Abstract

1. The role of peripheral 5-hydroxytryptamine (5-HT 3) receptors and cholecystokinin type 1 (CCK 1) receptors in the inhibitory effects of phenylbiguanide (PBG) and CCK on arterial blood pressure, heart rate and the discharge of presympathetic vasomotor neurones of the rostral ventrolateral medulla (RVLM) was studied in α-chloralose-anaesthetized rats. 2 CCK (1 and 4/μg kg -1, i.v.) and PBG (2 and 10 μg kg -1, i.v.) reduced arterial blood pressure and heart rate, and inhibited the discharge of single RVLM presympathetic vasomotor neurones in a dose-related manner. 3 Devazepide (0.5 mg kg -1, i.v.), a selective CCK 1 receptor antagonist, blocked the effects of CCK on arterial blood pressure, ..