Studies were performed in healthy volunteers to determine the effects of catecholamines and adrenergic-blocking agents on plasma and urinary levels of adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP). Plasma cyclic AMP rose in response to infusions of the beta-adrenergic agent, isoproterenol, or in response to infusions of either epinephrine or norepinep...

In 1958, Powell and Slater (1) first described that DCI had beta-adrenergic blocking activity even though it included beta-adrenergic stimulations. Such property was found also in methoxamine besides its alpha-adrenergic stimulant activity (2, 3). In the follow ing decade, many beta-adrenergic blocking agents have been synthesized successively (4-8) and one of them, propranolol was first introd...

Alpha- and beta-adrenergic receptors were studied by measuring the binding of 3H-dihydroergocryptine and 3H-dihydroalprenolol, respectively, to membranes prepared from homogenized rabbit iris--ciliary bodies. The binding of 3H-dihydroergocryptine appears to be specific for alpha-adrenergic receptors, since adrenergic agents displace this radioligand with the following order of potency: phentola...

peaked positive chronotropic responses, i.e., rapidly induced initial acceleration followed by slowly induced but long-lasting one. The initial positive response to caffeine was hardly suppressd by either adrenergic beta-blocking agents, H 56/28 (alprenolol) and propranolol, or tetrodotoxin. On the contrary, the secondary positive chronotropic response was effectively inhibited by either adrene...

When examined by fluorescence microscopy the rabbit basilar artery contains a rich adrenergic-like plexus at the adventitiomedial junction. The fluorescence disappears upon chronic reserpinization and bilateral superior cervical ganglionectomy. Transmural stimulation of intramural nerves a results in a response which is predominantly constrictor but also contains a small, inconstant dilator com...

The pharmacologic response of bladder muscle strip of albino rabbits was studied in vitro. The effect of cholinergic and adrenergic agents and their antagonists were demonstrated with a log dose-response curve. Cholinergic receptors were abundant in detrusor muscle. While the excitory alpha adrenergic receptors existed in bladder neck, the inhibitory beta adrenergic receptors were predominant i...

Recently interest in investigations of adrenergic agents (stimulants and inhibitors) on gastric secretion, motility, and ulceration in experimental animals has increased (1-7). Pradhan and Wingate (6) have demonstrated that phentolamine and tolazoline enhanced the spontaneous gastric secretion in dogs while phenoxybenzamine and dichloroisopro terenol showed inhibitory effects on spontaneous as ...