Background. (-Adrenergic receptor blockade has been reported to improve hemodynamics and 3-adrenergic receptor-adenylate cyclase function in idiopathic dilated cardiomyopathy. The purpose of this study was to determine the effects of 3-adrenergic receptor blockade on the 13-adrenergic receptor system and myocardial function in a model of compensated ischemic heart failure. Methods and Results. ...

In contrast to antipsychosis drugs which inhibit the dopamine-activated adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] of caudate nucleus, dopaminergic drugs for treatment of Parkinson's disease stimulate this cyclase. Stimulants and inhibitors of cholinergic neurons inhibited this adenylate cyclase activity competitively and specifically. Thus, the mechanism by which dopam...

1. Intact mouse neuroblastoma NS20 cells, in the presence of cyclic adenosine 3':5'-monophosphate (cAMP) phosphodiesterase inhibitor, responded to adenosine (200 muM) and 2-chloroadenosine (200 muM) with a 20-fold increase in intracellular cAMP levels. AMP (200 muM) additions caused only a 3.5-fold cAMP level elevation. ATP, ADP, guanosine, cytidine, uridine, and guanine, all at 200 muM, had no...

Background. (-Adrenergic receptor blockade has been reported to improve hemodynamics and 3-adrenergic receptor-adenylate cyclase function in idiopathic dilated cardiomyopathy. The purpose of this study was to determine the effects of 3-adrenergic receptor blockade on the 13-adrenergic receptor system and myocardial function in a model of compensated ischemic heart failure. Methods and Results. ...

Similarities exist between the properties of adenylate cyclase after stimulation by cholera toxin and after stimulation by guanylylimidodiphosphate (Gpp-(NH)p). Thus a strong stimulation is achieved by both agents, the stimulation is essentially irreversible, the action of certain hormones is enhanced and the enzyme can be solublized with Lubrol PX in the activated state. Because of these simil...

The extracellular concentration of cyclic adenosine 3',5'-monophosphate (AMP) of three different strains of Vibrio cholerae growing in syncase medium were measured. Cyclic AMP secreted by V. cholerae 569B varied widely, with different carbon sources. Mutant 13, which produced little or no toxin, released half the amount of cyclic AMP as the wild type. The release of less cyclic AMP into the med...

Serotonin activates adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] of NCB-20 neuroblastoma--brain hybrid cells with an activation constant of 530 nM, but has little or no effect on cellular cyclic AMP or cyclic GMP content of NIE-115 neuroblastoma or NG108-15 hybrid cells. In homogenates of NCB-20 hybrid cells, lysergic acid diethylamide stimulates adenylate cyclase activit...

The appearance of P-adrenergic receptors and isoproterenol-stimulated adenylate cyclase during differentiation of embryonic quail muscle cells in tissue culture has been examined. P-Adrenergic receptors first appear during the fusion stage of myogenesis. ['"I]]Iodohydroxybenzylpindolol (['2sI]IHYP) was used as the ligand to characterize &adrenergic receptors. In equilibrium binding studies, mat...

Pigmented rabbits were given an intravitreous injection of 0.1 ml of various concentrations of test drug, and vitreous fluorophotometry was done 6 and 24 hr after injection. Dibutyryl cyclic adenosine monophosphate (AMP) and 8-bromo-cyclic AMP caused reversible intravitreous fluorescein leakage only at relatively high concentrations. Adrenergic agents that are effective stimulators of adenylate...