title: Inotropic effects of tanghinin and acetyl-tanghinin on guinea-pig isolated papillary muscle.
abstract: Tanghinin and its acetylated derivative acetyl-tanghinin are two cardiotonic glycosides isolated from the seed of Tanghinia venenifera Poir. (Apocynaceae). In vitro, these two heterosides increase the contractile force of the guinea-pig papillary muscle. At an extracellular concentration of 1.2 mM of CaCl2, a concentration of 2.8 x 10(-6) M of tanghinin or acetyl-tanghinin increased muscle tension with 1.3 g and 1.5 g, respectively. In presence of an extracellular concentration of 2.4 mM of CaCl2, maximal effects--1.8 g for tanghinin and 2.2 g for acetyl-tanghinin--were obtained with a glycoside concentration of 2.4 x 10(-6) M. These maximal effects are sustained up to a concentration of 2.8 x 10(-6) M. At higher concentrations, the positive inotropic effect drops rapidly, followed by a rise in diastolic tension.
authors.affiliation: Laboratory of Pharmacology, E.E.S. Sciences, Antananarivo, Madagascar.
authors.forename: F
authors.initials: F
authors.lastname: Randimbivololona
authors.forename: N
authors.initials: N
authors.lastname: Rakotomanga
mesh_terms: D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D002301:Cardiac Glycosides / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal
chemical_list: D002301:Cardiac Glycosides; D010936:Plant Extracts; C069007:tanghinin; C069008:acetyltanghinin; D002122:Calcium Chloride