Central Neuropeptide W administration elicits a pressor response due, in part, to mesenteric vasoconstriction in conscious rats

Abstract

Neuropeptide W (NPW) is a centrally acting peptide that activates the central melanocortin system and increases arterial pressure in conscious rats. We investigated the mechanism by which NPW evokes hemodynamic responses. Rats were instrumented for recording arterial pressure and for measuring blood flow changes in the abdominal aorta (hindquarters) and the superior mesenteric artery using pulsed Doppler flowmetry. Intracerebroventricular NPW (0.3 nmol and 1 nmol) elicited a pressor response of 9.6±3 and 10.6±4.9 mmHg, respectively, occurring between 90 and 180 seconds after administration. There was a concomitant increase in heart rate (27±10 and 30±12 b/min) and increase in mesenteric vascular resistance (26±8 and 28±10%). Therefore, the increase in arterial pressure due to central administration of NPW is at least partially dependent on increased mesenteric vascular resistance. Hindquarters vascular responses were minimal and highly variable. We conclude that central NPW evokes mesenteric vasoconstriction and tachycardia contributing to a pressor response similar to a classical behavioral stress response. Supported by USPHS DA017371.