Effects of neuropeptide Y on the heart and circulation of the conscious rabbit.

Journal of Cardiovascular Pharmacology
R B MinsonJ P Chalmers

Abstract

The direct and reflex-mediated components of the cardiovascular response to administration of neuro-peptide Y (NPY) in intact conscious rabbits were determined by studies with cardiac beta adrenoceptor and vagal blockade, and during total autonomic blockade. Cardiac pacing was used to prevent bradycardia, and sinoaortic denervation (SAD) was used to remove afferent baroreflex input. In control animals, NPY (10 micrograms/kg bolus i.v.) caused arterial pressure to increase from 77.4 +/- 1.5 mm Hg (mean +/- SEM) to a maximum of 91.4 +/- 1.6 mm Hg (p less than 0.05). This pressor response was independent of autonomic effectors but was buffered by arterial baroreflexes. The fall in heart rate (HR) from 281 +/- 14 to 252 +/- 18 beats/min (p less than 0.05) was mediated in part through baroreceptor-dependent changes in cardiac autonomic efferent activity, but was in part independent of autonomic neural mechanisms. Peak left ventricular (LV)dP/dt fell from 5,551 +/- 342 to 4,182 +/- 394 mm Hg/s (p less than 0.05) following NPY in control rabbits. This reduction was maintained during pacing and following SAD, and was caused partly by a withdrawal of cardiac beta-adrenergic tone and partly through a non-beta-mediated myocardial depressi...Continue Reading

Citations

Jan 1, 1990·Clinical and Experimental Pharmacology & Physiology·R B MinsonJ P Chalmers
Feb 1, 1996·Clinical and Experimental Hypertension : CHE·P Roberts-ThomsonJ P Chalmers
Feb 26, 1998·Journal of Applied Physiology·S A Lang, M B Maron

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