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Myocardial and haemodynamic effects of phentolamine
Author(s) -
DAS P. K.,
PARRATT J. R.
Publication year - 1971
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1971.tb08041.x
Subject(s) - phentolamine , contractility , bretylium , reserpine , medicine , blood pressure , heart rate , propranolol , cardiac output , hemodynamics , sympathetic nervous system , anesthesia , cardiology , adrenergic , receptor
Summary1 In cats anaesthetized with pentobarbitone, intravenous infusions of phentolamine ((10–50 μg/kg)/min for 5 min) increased heart rate, left ventricular dp/dt max (without increasing end‐diastolic pressure), aortic dp/dt , cardiac output, myocardial blood flow and metabolic heat production. 2 Phentolamine‐induced increases in myocardial contractility occurred irrespective of the direction or magnitude of the blood pressure change and were maintained well beyond the actual infusion period. 3 In cats treated with alprenolol, bretylium or reserpine there was no evidence of increased cardiac contractility following phentolamine administration. 4 It is concluded that phentolamine, in doses less than those required to produce significant α‐adrenoceptor blockade, increased myocardial contractility through an effect on the sympathetic nervous system.