title: Effects of sodium pentobarbital on rat heart sarcolemma.
abstract: The effects of sodium pentobarbital on ATPase, Ca2+ binding and adenylate cyclase activities of the rat heart sarcolemmal preparations were investigated. The Na+ - K+ ATPase activity was diminished by pentobarbital in concentrations as low as 0.3 mM. Mg2+ ATPase, Ca2+ ATPase and adenylate cyclase activities were also depressed but required 10 to 15 mM of this agent. Pentobarbital in concentrations of 10 mM, however, caused an increase in sarcolemmal Ca2+ binding. Mitochondrial and microsomal ATPase activities were decreased by 1 and 5 mM concentrations of pentobarbital respectively, while myofibrillar ATPase activity was unaltered even at a concentration of 20 mM. These data suggest that cardiodepressant effects of high doses of pentobarbital may partly be explained on the basis of its actions on heart sarcolemma.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D009210:Myofibrils / Q000187:drug effects / Q000378:metabolism; D010424:Pentobarbital / Q000494:pharmacology*; D051381:Rats; D012508:Sarcolemma / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000251:Adenosine Triphosphatases; D000262:Adenylyl Cyclases; D010424:Pentobarbital; D002118:Calcium