Endothelin, a 21-amino acid vasoactive peptide, is among the most potent positively inotropic agents yet described in mammalian heart. Having demonstrated that endothelin's inotropic effect is due, in part, to an apparent sensitization of cardiac myofilaments to intracellular calcium, we determined whether this could be due to a rise in intracellular pH (pHi). In isolated adult rat ventricular ...

Isoproterenol increases and decreases contractile force at low and high concentrations, respectively, through beta(2)-adrenoceptors overexpressed in transgenic mouse heart (TG4), consistent with activation of both G(s) and G(i) proteins. Using TG4 hearts, we demonstrated that epinephrine behaves like isoproterenol, but norepinephrine does not. Epinephrine both increased (-log EC(50)M = 9.4) and...

In blood-perfused isolated canine atrium preparations, single injections of dibutyryl cyclic AMP at a dose range of 1 to 30 mg were made into the cannulated sinus node artery. At doses above 3 mg, dibutyryl cyclic AMP induced a biphasic chronotropic and inotropic response; there was a slight and rapid negative chronotropic and inotropic response, followed by a long-lasting positive chronotropic...

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) may serve as a new assay for drug testing in a human context, but their validity particularly for the evaluation of inotropic drug effects remains unclear. In this blinded analysis, we compared the effects of 10 indicator compounds with known inotropic effects in electrically stimulated (1.5 Hz) hiPSC-CM-derived 3-dimensional...

OBJECTIVES To assess the validity of Vasoactive-Inotropic Score as a scoring system for cardiovascular support and surrogate outcome in pediatric sepsis. DESIGN Secondary retrospective analysis of a single-center sepsis registry. SETTING Freestanding children's hospital and tertiary referral center. PATIENTS Children greater than 60 days and less than 18 years with sepsis identified in th...

Right ventricular (RV) failure is a serious common clinical problem that is poorly understood. Therefore, for failing and nonfailing hearts, we examined the distinctive inotropic responses induced in the RV myocardium after the stimulation of alpha(1)-adrenergic receptors (ARs). In RV trabeculae from nonfailing mouse hearts, alpha(1)-ARs induced a negative inotropic response, consistent with ou...

The positive inotropic action of hexainethoniuin in hypodynamic and freshly prepared papillary muscles of the cat and the hypodynamic heart-lung preparation of the dog has been demonstrated. Within certain limits, there exists a proportionality between the concentration of hexamethonium and the magnitude of the inotropic response. In both preparations results have been obtained which indicate t...

OBJECTIVE Inotrope score has been proposed as a marker of illness severity after pediatric cardiac surgery despite a lack of data to support its use as such. The goal of this study was to determine the association between inotropic/vasoactive support and clinical outcome in infants after cardiac surgery. DESIGN Retrospective chart review. SETTING Dedicated pediatric cardiothoracic intensive...

Endothelin, a 21-amino acid vasoactive peptide, is among the most potent positively inotropic agents yet described in mammalian heart. Having demonstrated that endothelin's inotropic effect is due, in part, to an apparent sensitization of cardiac myofilaments to intracellular calcium, we determined whether this could be due to a rise in intracellular pH (pHi). In isolated adult rat ventricular ...

Objective. The objective of this study was to investigate the inotropic mechanisms and the related muscarinic receptor subtype of acetylcholine (ACh) in canine cardiac Purkinje fibers. Materials and Methods. Isolated Purkinje fiber bundles were used for the measurement of contraction. The receptor subtype was determined using PCR and real-time PCR methods. Results. ACh evoked a biphasic respons...