Effects of vanadate on heart and circulation.
In anesthetized cats vanadate (Na3VO4) up to 0.5 mg/kg increased blood pressure and left ventricular end-diastolic pressure (LVEDP) but decreased the force of contraction and heart rate. At 1 mg/kg, LVEDP increased markedly in parallel with an elevation of the ST segment of the electrocardiogram and a pronounced decrease in blood pressure; these effects were reversible within a few minutes. In isolated Langendorff heart preparations of guinea pigs perfused at constant pressure, vanadate decreased flow rate (EC50 = 5.3 mumoles/liter) and contractile force (EC50 = 6.9 mumoles/liter). Vanadate increased tension in isolated aortic strips of cats (EC50 = 115 mumoles/liter) and rabbits (EC50 = 435 mumoles/liter). Vanadate also increased the force of isometric contractions of papillary muscles of guinea pigs, cats, and rabbits, the EC50 values being 124, 110, or 66 mumoles/liter, respectively. We conclude that the negative ionotropic action of vanadate is brought about by marked coronary constriction occurring at concentrations which are too low to have a direct positive action on ventricular myocardium.
D000818:Animals; D001011:Aorta / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D002415:Cats; D003331:Coronary Vessels / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects; D011817:Rabbits; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects
D014639:Vanadium; D014638:Vanadates