title: Effects of tabernanthine on calcium and catecholamine stimulated contractions of isolated vascular and cardiac muscle.
abstract: The Iboga alkaloid tabernanthine (80 microM) non-competitively antagonized contractions in both the rat aorta and mesenteric artery induced by cumulative additions of noradrenaline and calcium. Tabernanthine (8, 40 and 80 microM) antagonized the K+ depolarization-induced contractions of the aorta. Tabernanthine (80 microM) depressed the phasic component of contractions induced by a single maximal concentration (10 microM) of noradrenaline in Ca++ -free solution. Tabernanthine induced a negative inotropic effect in electrically stimulated myocardial tissue and a negative chronotropic effect in the perfused rat heart. Tabernanthine is a calcium entry blocker which also affects cellular calcium metabolism.
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002395:Catecholamines / Q000494:pharmacology*; D004558:Electric Stimulation; D005260:Female; D007050:Ibogaine / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000470:Alkaloids; D002395:Catecholamines; D007050:Ibogaine; D011188:Potassium; D002118:Calcium; C027202:tabernanthine; D009638:Norepinephrine