ISSN:
1435-1803
Keywords:
heart sarcolemma
;
Ca2+-stimulated ATPase
;
ATP-dependent Ca2+ binding
;
β-adrenergic antagonists
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The effects of some β-adrenergic antagonists such as acebutolol, propranolol, pindolol and oxprenolol (1–1000 μM) were studied on the rat heart sarcolemmal Ca2+ transport activities. Pindolol enhanced sarcolemmal ATP-dependent Ca2+ binding and Ca2+-stimulated ATPase whereas acebutolol had no effect. Both propranolol and oxprenolol had biphasic actions on the sarcolemmal Ca2+ pump activities; the lower concentrations (1 and 10 μM) were stimulatory, but the higher concentrations (100 and 1000 μM) were inhibitory. None of the drugs used in this study had any effect on Mg2+ ATPase and non-specific Ca2+ binding activities of heart sarcolemma except that 1000 μM propranolol decreased Mg2+ ATPase activity significantly. Mitochondrial and microsomal ATP-dependent Ca2+ binding activities were unaffected by these drugs (1–1000 μM), except that 1000 μM propranolol was inhibitory. These results suggest differences among various β-adrenergic blocking drugs with respect to their actions on sarcolemmal Ca2+ pump in the myocardium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01908380
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