Interactions of cryptosin with mammalian cardiac beta-adrenoceptors.
Cryptosin - a new cardenolide from the leaves of Cryptolepis buchanani R & S was found to be a potent positive inotropic agent. In experiments with dog heart ex vivo, the rise in the cardiac rate associated with an increase in dP/dtmax and left ventricular pressure (LVP) correlated with changes in the beta-adrenoceptor densities as measured by the binding of 3H-Dihydroalprenolol (DHA). A significant change in the beta-adrenoceptor densities was observed when cryptosin was incubated with guinea pig and dog heart sarcolemmal membranes in vitro. Analysis of the binding of 3H-DHA in post-cryptosin treated membranes indicated a non-specific type of interaction of cryptosin with mammalian cardiac beta-adrenoceptors.
Rao
V R
VR
Department of Pharmacology, College of Pharmacy and Allied Health Professions, Wayne State University, Detroit, MI 48202.
Banning
J W
JW
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002301:Cardiac Glycosides / Q000494:pharmacology* / Q000633:toxicity; D002316:Cardiotonic Agents / Q000494:pharmacology* / Q000633:toxicity; D004082:Dihydroalprenolol / Q000031:analogs & derivatives / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D008566:Membranes / Q000378:metabolism; D009206:Myocardium / Q000648:ultrastructure*; D011943:Receptors, Adrenergic, beta / Q000494:pharmacology* / Q000502:physiology; D012508:Sarcolemma / Q000648:ultrastructure; D014316:Tritium
D000319:Adrenergic beta-Antagonists; D002301:Cardiac Glycosides; D002316:Cardiotonic Agents; D011943:Receptors, Adrenergic, beta; D014316:Tritium; C060095:cryptosin; C057093:1-(4,6-propyl)dihydroalprenolol; D004082:Dihydroalprenolol