Actions of dibutyryl cyclic adenosine monophosphate, papaverine and isoprenaline on the intestinal smooth muscle.

Actions of papaverine on intestinal smooth muscle and its inhibition of cyclic AMP and cyclic GMP phosphodiesterases.

Papaverine, a nonspecific smooth muscle relaxant, is well known to be a potent cyclic AMP phosphodiesterase inhibitor (1, 2). In recent papers (3-8) it has been reported that smooth muscle relaxing action of papaverine is likely to be mediated through an increase of cyclic AMP due to its phosphodiesterase inhibition. Recently attention has drawn to the role of cyclic GMP, which often presents p...

Action of dibutyryl cyclic adenosine monophosphate on the intestinal smooth muscle.

Mechanism of relaxant action of papaverine. Effect on caffeine-induced contraction of guinea pig taenia coli.

The mode of action of papaverine on smooth muscle relaxation was examined through analyzing its effects on caffeine-induced contraction of guinea pig taenia coli, which might be due to calcium ion mobilized from intracellular store sites. Caffeine contraction induced in normal solution at 32 degrees C was decreased in the presence of papaverine but increased after the removal of papaverine, and...

Correlation of cyclic AMP and cyclic GMP levels with changes in contractile force of dog ventricular myocardium during cholinergic antagonism of positive inotropic actions of histamine, glucagon, theophylline and papaverine.

On the dog isolated right ventricular muscle, experiments were carried out in order to elucidate the characteristics of the cholinergic antagonism against the positive inotropic action (PIA) induced via different subcellular mechanisms. The relationship between cyclic AMP and cyclic GMP levels, and contractile force during cholinergic antagonism was assessed. Carbachol (10 microM) by itself dec...

BRIEF COMMUNICATIONS Adenosine 3',5'-Cyclic-Monophosphate-Dependent Regulation of «i-Adrenergic Receptor Number in Rabbit Aortic Smooth Muscle Cells

The purpose of this study was to determine whether a cyclic adenosine 3',5'monophosphate-dependent process can be involved in the regulation of vascular smooth muscle ai-adrenergic receptor responsiveness. Experiments were performed in cultured rabbit aortic smooth muscle cells which were characterized previously according to a-adrenergic receptorbinding characteristics and receptor-coupled nor...