The effect of X-537A (lasalocid) on potassium contracture in rat ventricular muscle.
The effects of the carboxylic ionophore X-537A on contracture induced by high external K+ were determined in stimulated and unstimulated rat papillary muscles. X-537A (5 X 10(-6) M - 10(-5) M) increased peak K+-contracture force in stimulated but not unstimulated muscle. X-537A may alter myocardial force development by influencing transport of Ca2+ across the sarcolemma or Ca2+ release from sarcoplasmic reticulum.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D007832:Lasalocid / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects; D012519:Sarcoplasmic Reticulum / Q000378:metabolism
D011941:Receptors, Adrenergic; D011189:Potassium Chloride; D011188:Potassium; D002118:Calcium; D007832:Lasalocid