This study tests the hypothesis that particulate (p) guanylyl cyclase (GC) and soluble (s) GC are involved in the distinct roles for the regulation of cGMP-PDE-cAMP signaling and of mechanical and secretory functions in the heart. Experiments were performed in perfused beating rabbit atria. C-type natriuretic peptide (CNP) and SIN-1, an NO donor, or BAY 41-2272 (BAY), a direct activator for sGC...

BACKGROUND Structural and phenotypic changes of cardiomyocytes characterize atrial fibrillation. We investigated whether changes in the glucose-regulated protein GRP94, which is essential for cell viability, occur in the presence of chronic atrial fibrillation. METHODS AND RESULTS Samples of fibrillating atrial myocardium obtained from both goat and human hearts were analyzed for GRP94 expres...

Ouabain increases atrial natriuretic peptide (ANP) secretion. When isolated superfused rat left atria were paced at 2 Hz, ouabain at concentrations of 50, 100, and 200 microM increased ANP secretion by 2.0 +/- 0.3-, 3.2 +/- 0.5-, and 4.2 +/- 0.5-fold, respectively. In this study, we examine the mechanism of ouabain-stimulated ANP secretion using the dose of 100 microM. To determine whether calc...

Intravenous (bolus) administration of endothelin results in a transient fall in blood pressure that is accentuated in spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto normotensive rats (WKY). In attempting to discern possible mechanisms underlying this depressor response, we examined the ability of endothelin to release atrial natriuretic factor (ANF) from isolated, spontaneousl...

The purpose of the present study was to investigate alpha 1-adrenergic receptors in the heart as well as the activity and the sensitivity of the phosphoinositide pathway on tissue slices of atria, ventricles, and femoral artery of hypertensive rats treated for 4 weeks with deoxycorticosterone acetate (DOCA) and 1% saline. DOCA-salt hypertensive rats were characterized by an increased sympathoad...

The differential effects of a selective kappa- (κ-) opioid receptor agonist, U50488, were elucidated by monitoring the contraction of isolated guinea pig atrial and ventricular muscles. In electrically driven left atria, U50488 in nanomolar concentration range decreased the contractile force. Norbinaltorphimine (norBNI), a selective κ-receptor antagonist, and pertussis toxin (PTX) abolished the...

In 1969, the Servier Laboratoires introduced trimetazidine, 1-(2, 3, 4-trimethoxybenzyl) piperazine dihydrochloride (Vastarel®) as a medicament for angina pectoris (1). This drug is assumed to reveal its remarkable action through decreasing cardiac work and lower ing the oxygen consumption of the heart (2), but other mechanisms of its action yet await ed clarification. Since trimetazidi...

Fourteen relatively long term survivors of cardiac transplantation underwent systematic electrophysiological evaluation and ambulatory electrocardiographic monitoring. Six patients had prolonged conduction intervals during sinus rhythm. Sinus node function could be assessed in all donor atria and in 10 recipient atria. Sinus node recovery times were prolonged in four of the donor atria and in s...

The goal of this study was to test the hypothesis that the relative amounts of the cardiac myosin heavy chain (MHC) isoforms MHC-alpha and MHC-beta change during development and transition to heart failure in the human myocardium. The relative amounts of MHC-alpha and MHC-beta in ventricular and atrial samples from fetal (gestational days 47--110) and nonfailing and failing adult hearts were de...

The mechanism of cardiac actions of rat calcitonin gene-related peptide (CGRP) was analyzed on isolated guinea pig hearts. CGRP exerted a positive inotropic effect in a dose-dependent manner on the electrically driven left atria but not on the ventricles. Immunohistochemical studies demonstrated that CGRP-like immunoreactive nerves were distributed densely in the myocardia of the atria but only...