title: Charged amphiphiles regulate heart contractility and sarcolemma-Ca2+ interactions.
abstract: We have used charged amphiphiles as phospholipid analogues to modulate the interaction of Ca2+ with myocardial sarcolemma. The amphiphiles were dodecyl sulfate, dodecyltrimethylamine, and lauryl acetate; these are anionic, cationic, and neutral molecules, respectively. The hydrophobic alkyl chain is identical in each case; only the hydrophilic head group is varied. The anionic dodecyl sulfate (50-100 microM) augmented the Ca2+ binding and Na+-Ca2+ exchange activity of sarcolemmal vesicles by approximately 80% and increases the contractility of rabbit papillary muscle. Both developed force and its derivative were increased by approximately 100% with no increase in rest tension. Cationic dodecyltrimethylamine (20-100 microM) produced nearly opposite effects. Neutral lauryl acetate (100 microM) had little apparent effect on any measurement. The charged amphiphiles should be useful tools for further elucidation of excitation-contraction coupling processes in a variety of contractile tissues.
mesh_terms: D000085:Acetates / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002412:Cations / Q000378:metabolism / Q000494:pharmacology; D004285:Dogs; D005233:Fatty Alcohols / Q000494:pharmacology*; D007474:Ion Exchange; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D010210:Papillary Muscles / Q000187:drug effects; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D011817:Rabbits; D012508:Sarcolemma / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate
chemical_list: D000085:Acetates; D002412:Cations; D005233:Fatty Alcohols; D000644:Quaternary Ammonium Compounds; D012967:Sodium Dodecyl Sulfate; C044215:lauryl acetate; D012964:Sodium; C028913:dodecyl sulfate; C022806:dodecyltrimethylammonium; D002118:Calcium