Direct cardiac actions of phenylephrine when used in assessment of baroreflex function in the rat

Journal of Autonomic Pharmacology
R Sawyer, J R Docherty

Abstract

In pentobarbitone-anaesthetised wistar rats, the baroreflex bradycardia in response to the vasopressor agent phenylephrine was converted to a tachycardia by propranolol. In pithed wistar rats, phenylephrine produced a marked tachycardia which was mediated largely by beta-adrenoreceptors since propranolol markedly antagonised the response. A component of the tachycardia was mediated by alpha 1-adrenoreceptors since the tachycardia to phenylephrine in the presence of propranolol was antagonised by prazosin and mimicked by the alpha 1-adrenoreceptor agonist amidephrine. It is concluded that phenylephrine is not a useful agent for assessment of baroreflex function in the rat due to its marked cardiac stimulant actions.

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Citations

Jan 11, 1992·Clinical and Experimental Hypertension. Part A, Theory and Practice·A BrattströmL Pharow
Feb 1, 2012·Neuropathology and Applied Neurobiology·P S PahlavanM R Del Bigio
Mar 21, 2006·European Journal of Pharmacology·David CenturiónCarlos M Villalón
Nov 15, 2002·Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc·Dirk RamaekersAndré E Aubert

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