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Free keywords:
Calcium; β-Adrenoceptor Blocker; Adenosine Triphosphatase; Nucleotides; Sarcoplasmic Reticulum
Abstract:
The rates of calcium uptake and the calcium dependent increase in ATPase activity of sarcoplasmic reticulum vesicles isolated from rabbit skeletal muscle are reduced in the same ratio by the β-adrenoceptor blocking agents propranolol, pronethalol and Ro-03,3528, but neither by practolol, sotalol nor oxprenolol. The total calcium accumulated was affected by none of the inhibitors.
The inhibitory potency of these compounds upon the calcium pump appears to be correlated with their membrane activity or potency as local anaesthetic agents, rather than with their β-adrenoceptor blocking potency.
Like the rate of calcium uptake the rate of calcium efflux from the sarcoplasmic vesicles in the presence of ADP, GPD and UDP together with phosphate is inhibited by propranolol and pronethalol.