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THE ANTAGONISM BY PROPRANOLOL AND α‐METHYLPROPRANOLOL (ICI 77602) OF VASCULAR AND CARDIAC RESPONSES TO ISOPRENALINE IN ANAESTHETIZED DOGS
Author(s) -
Fitzgerald J. D.,
O'Donnell Stella R.
Publication year - 1978
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1978.tb00713.x
Subject(s) - propranolol , isoprenaline , cardiac output , potency , medicine , antagonist , hindlimb , antagonism , perfusion , heart rate , blood pressure , anesthesia , endocrinology , pharmacology , chemistry , receptor , stimulation , in vitro , biochemistry
SUMMARY 1. In anaesthetized dogs, α‐methylpropranolol was less potent than propranolol in antagonizing both vascular (hind limb perfusion pressure) and cardiac heart rate) responses to isoprenaline. 2. α‐Methylpropranolol was more potent in antagonizing vascular than cardiac responses to isoprenaline, but this selectivity was no greater than that seen also with propranolol. 3. Isoprenaline sensitivity was greater in the hind limb than the heart and vascular‐selective antagonism was more pronounced in those dogs in which this differential sensitivity was the greatest. 4. Introduction of an a‐methyl group into propranolol decreases its 0‐adrenoceptor antagonist potency but does not enhance vascular selectivity.