NMDA receptors in the nucleus of the solitary tract contribute to the splanchnic sympathoinhibitory effects of cholecystokinin

Abstract

Cholecystokinin (CCK) elicits a sympathetic vasomotor reflex that may play an important role in regulating gastrointestinal blood flow. The aim of this study was to identify the significance of excitatory amino acid (EAA) receptors in the nucleus of the solitary tract (NTS) in this reflex. We recorded arterial blood pressure, heart rate and splanchnic sympathetic nerve discharge (SSND) in halothane anesthetised, paralysed, male Sprague‐Dawley rats. In separate groups of rats, the sympathoinhibitory effects of baroreflex activation (phenylephrine, PE; 10 μg/kg i.v.), von Bezold‐Jarisch reflex activation (phenylbiguanide, PBG; 10 μg/kg i.v.) and CCK (4 μg/kg, i.v.) were tested before and after..