Optically active isomers of N-methy1-2-(2-(2-(4-phenylpiperazino)ethoxy)phenyl)thiazolidine3-carboxamides(( + )-2 and(-)-2) have been synthesized and tested for positive inotropic activity. The racemic thiocarboxamide((•})-3) was resolved into the enantiomers(( + )-3 and(•E)-3) via the Land D-N-(2-naphthylsulfonyl)prolyl derivatives ((+ )-4 and (-)-4). Conversion of the thiocarboxamides (( + )-...

for geriatric patients. The negative inotropic effect of sympathomimetic amines has scarcely been reported in rature. Wenzel and Su (3), while studying the interactions of sympathomimetic amines with ir antagonists on isolated rat ventricular strips, observed that phenylephrine initially produceda negative inotropic effect which was later on followed by usual positive inotropic response. imilar...

Veratridine is a sodium channel toxin that exerts a powerful positive inotropic effect and prolongs the action potential duration in the heart. To determine the basis of the inotropic action of veratridine and to examine the effects of dissimilar methods of raising intracellular sodium activity on contractility, we measured twitch tension and intracellular sodium activity using sodium-sensitive...

Reports in the literature have indicated that inotropic responsiveness to isoproterenol (ISO) of hypertrophied rat myocardium is decreased. We have studied possible biochemical mechanisms to explain this. Adenylate cyclase activity in myocardial membranes from 13-week-old spontaneously hypertensive rats (SHR) was unchanged compared to enzyme activity in Wystar-Kyoto (WKY) when measured under ba...

We studied the relationships between the positive inotropic effects of isoproterenol, increased frequency of contraction or paired electrical stimulation, and cyclic AMP concentration and phosphorylase activity in isolated guinea pig papillary muscles. The minimum concentration of isoproterenol (10 nM) that augmented isometric force development increased cyclic AMP concentration. However 100 nM...

Sixteen healthy men were evaluated for left ventricular performance changes and beta-blockade after therapeutic oral doses of disopyramide and propranolol administered alone and concurrently. The volunteers were randomly assigned to receive one of two drug treatment regimens that differed in the sequence and duration of administration of the drugs. Left ventricular function was assessed by echo...

We systematically modified isoproterenol's chemical structure to reduce chronotropic, arrhythmogenic, and vascular side effects. Experiments on dogs showed that the resulting drug, dobutamine, had an inotropic efficacy as great as that of epinephrine due to a direct action on beta1 cardiac receptors. However, unlike epinephrine, dobutamine's effect on alpha and beta2 vascular receptors was slig...

OBJECTIVE To determine whether transient hypoxia in neonatal rats has long-lasting effects on inotropic stimulation of the adult heart. METHODS The hearts of adult male Sprague-Dawley rats (89+/-1 (S.E.M.) days, 432+/-5 g) were studied. Half the animals had been subjected to neonatal hypoxia (FiO(2)=0.12, days 1-10) while the others had not. The peak response of left ventricular pressure (LVP...