Background: Selective phosphodiesterase (PDE3) inhibitors improve cardiac contractility and may use in congestive heart failure. However, their proarrhythmic potential is the most important side effect. Methods: In this research, we evaluated the potential cardiotonic activity of six new synthesized selective PDE3 inhibitors (6-hydroxy-4-methylquinolin-2(1H)-one derivatives) using the spontan...

acrylamide gel. A highly active substance was isolated by ion-exchange chromatography on a 5 % cross-linked polymer ofacrylamide, NN'-methylenebisacrylamide and diethylaminoethyl methacrylate. 2. The initial gel-filtration experiments were carried out under a wide variety of conditions and resulted in the same yield of high-molecularweight and low-molecular-weight fractions with inotropic activ...

Both bethanechol and physostigmine produced dose-dependent negative chrono-, dromo- and inotropic effects in the dog isolated atrial preparation. Within a relatively small dose of bethanechol and physostigmine, negative inotropic effect was clearly induced but no significant chrono- and dromotropic changes were observed. With a relatively large dose, the two cholinomimetics caused negative chro...

BACKGROUND Extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (p38-MAPK) have been shown to regulate various cellular processes, including cell growth, proliferation, and apoptosis in the heart. However, the function of these signaling pathways in the control of cardiac contractility is unclear. Here, we characterized the contribution of ERK1/2 and p38-M...

We studied the effect of vagal afferents on the left ventricular contractile response (LVdP/dtmax) to administration of sympathomimetic amines into the left circumflex coronary artery in conscious dogs. The positive inotropic effects of bolus administration of epinephrine, norepinephrine, and isoproterenol were greater during bilateral vagal cold block (BVB) that in the control state with the v...

BACKGROUND AND PURPOSE Despite the view that only β2- as opposed to β1-adrenoceptors (βARs) couple to G(i), some data indicate that the β1AR-evoked inotropic response is also influenced by the inhibition of Gi. Therefore, we wanted to determine if Gi exerts tonic receptor-independent inhibition upon basal adenylyl cyclase (AC) activity in cardiomyocytes. EXPERIMENTAL APPROACH We used the Gs-s...

2,3-dehydrosilybin (DHS) is a minor flavonolignan component of Silybum marianum seed extract known for its hepatoprotective activity. Recently we identified DHS as a potentially cardioprotective substance during hypoxia/reoxygenation in isolated neonatal rat cardiomyocytes. This is the first report of positive inotropic effect of DHS on perfused adult rat heart. When applied to perfused adult r...

Peripheral vascular effects of opioid peptides are well known, but direct myocardial effects have not been established. We studied the inotropic response of spontaneously beating cultured chick embryo ventricular cells to the enkephalin analogue [D-Ala2]-enkephalin. Amplitude of cell motion increased in a concentration-dependent manner with 0.53 microM [D-Ala2]-enkephalin producing half-maximal...