title: Inhibition of beta-adrenergic stimulated calcium pump of rat cardiac sarcoplasmic reticulum by tricyclohexyltin hydroxide.
abstract: The effects of tricyclohexyltin hydroxide (Plictran), an organotin acaricide, on 45Ca2+ uptake and Ca2+ ATPase were studied in vitro and in vivo in rat heart ventricular membrane vesicles, primarily sarcoplasmic reticulum. There was a concentration dependent inhibition of both 45Ca2+ uptake and Ca2+ ATPase in vivo as well as in vitro. Isoproterenol, a beta-adrenergic agonist, stimulated 45Ca2+ uptake and Ca2+ ATPase of sarcoplasmic reticulum and this was also inhibited by Plictran. Since cardiac relaxation is mediated by beta-adrenergic stimulation via Ca+ uptake by sarcoplasmic reticulum, the inhibition of calcium pump activity by Plictran may result in alterations in cardiac Ca2+ fluxes leading to cardiac dysfunction.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D066298:In Vitro Techniques; D007306:Insecticides / Q000494:pharmacology*; D007545:Isoproterenol / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D014220:Trialkyltin Compounds / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D007306:Insecticides; D014220:Trialkyltin Compounds; C001765:cyhexatin; D000252:Calcium-Transporting ATPases; D007545:Isoproterenol; D002118:Calcium