The purpose of this study was to characterize by pharmacological means the inotropic action of prostaglandin D2 (PGD2) in the guinea-pig heart. In the whole heart perfused at constant pressure, PGD2 (0.01-10 micrograms) reduced coronary flow rate and decreased left ventricular contractile force in a dose-dependent manner. When the coronary vasoconstricting effect of PGD2 was antagonized by the ...

Mechanical function remains depressed for hours and days after even brief periods of ischemia. To determine whether the depressed function of the reperfused myocardium could be improved by inotropic stimulation, we studied segmental function during ischemia and after reperfusion using mercury-in-Silastic length gauges in 15 dogs. During coronary artery occlusion, segmental function could not be...

The actions of many hormones may be related to their capacity to increase adenyl cyclase activity in their target organs. The evidence indicating that catecholamines and glucagon augment myocardial contractility by enhancing the activity of myocardial adenyl cyclase is summarized. Furthermore, data are presented suggesting that the inotropic actions of epinephrine and glucagon ultimately may be...

The actions of many hormones may be related to their capacity to increase adenyl cyclase activity in their target organs. The evidence indicating that catecholamines and glucagon augment myocardial contractility by enhancing the activity of myocardial adenyl cyclase is summarized. Furthermore, data are presented suggesting that the inotropic actions of epinephrine and glucagon ultimately may be...

The experimental procedures to simultaneously detect contractile activity and Ca(2+) transients by means of the Ca(2+) sensitive bioluminescent protein aequorin in multicellular preparations, and the fluorescent dye indo-1 in single myocytes, provide powerful tools to differentiate the regulatory mechanisms of intrinsic and external inotropic interventions in intact cardiac muscle. The regulato...

There is scarce information about the effects of danazol and its derivatives at cardiovascular level. In addition, to date the cellular site and mechanism of action of danazol at the cardiovascular level is very confusing. In order to clarify those phenomena in this study, a danazol derivative was synthesized with the objective of evaluating its activity on perfusion pressure and coronary resis...

BACKGROUND Most volatile anesthetics exhibit a direct myocardial depressant effect. This side effect often limits their applicability in patients with impaired cardiac function. Xenon is a new gaseous anesthetic that did not show any adverse cardiovascular effects in clinical and experimental studies. The authors tested the hypothesis that xenon does not affect myocardial contractility or the p...

Adrenomedullin (ADM) is an endogenous peptide with favorable hemodynamic effects in vivo. In this study, we characterized the direct functional effects of ADM in isolated preparations from human atria and ventricles. In electrically stimulated human nonfailing right atrial trabeculae, ADM (0.0001-1 micromol/l) increased force of contraction in a concentration-dependent manner, with a maximal in...

Because of conflicting reports on the influence of extracellular potassium concentration ([K]o) on the inotropic action of cardiac glycosides, we compared the effects of varying [K]o (1.5, 4.5, and 7.5mM) on the inotropic action and myocardial concentration of tritiated digoxin (5 X 10~M) using the isolated cat papillary muscle. The time course of the inotropic response to digoxin was significa...