The beta-adrenoceptor blocking properties of the alpha-methyl analogues of propranolol and practolol in the anaesthetized dog

British Journal of Pharmacology
B Levy

Abstract

1. The beta-adrenoceptor blocking properties of alpha-methyl propranolol and alpha-methyl practolol were determined in anaesthetized dogs according to their abilities to modify the isoprenaline-induced effects on diastolic pressure, heart rate, myocardial contractile force, femoral arterial blood flow and pulmonary airway resistance.2. alpha-Methyl propranolol shifted the isoprenaline dose-response curves for the fall in diastolic pressure and the positive inotropic and chronotropic responses to the right in a parallel manner yielding pA(2) and slope values of 6.66 (0.92), 6.34 (0.77) and 6.59 (0.61) respectively. The slopes of the graphs for determining pA(2) values for the cardiac beta-adrenoceptor blocking properties of alpha-methyl propranolol were significantly less than 1 and indicated a mechanism other than simple, competitive, reversible antagonism.3. alpha-Methyl propranolol exerted a much weaker blockade of respiratory smooth muscle beta-adrenoceptors than has been reported for propranolol.4. alpha-Methyl practolol exerted a weaker blocking effect on myocardial beta-adrenoceptors than has been reported for practolol. No significant blockade of vascular or respiratory smooth muscle beta-adrenoceptors occurred after a t...Continue Reading

References

Jan 1, 1968·British Journal of Pharmacology and Chemotherapy·D Dunlop, R G Shanks
Feb 1, 1969·European Journal of Pharmacology·B Levy, B E Wilkenfeld
Aug 1, 1966·British Journal of Pharmacology and Chemotherapy·B Levy
Nov 1, 1953·Proceedings of the Society for Experimental Biology and Medicine·K J BONIFACER P WALTON
Mar 1, 1959·British Journal of Pharmacology and Chemotherapy·O ARUNLAKSHANA, H O SCHILD
May 16, 1964·Lancet·J W BLACKA C DORNHORST

Related Concepts

Airway Resistance
Metazoa
Diastolic Blood Pressure
Canis familiaris
Structure of Femoral Artery
Heart
Pulse Rate
Ceplene
Novodrin
Methylation

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