BACKGROUND AND PURPOSE CGP 12177 not only inhibits agonist effects mediated through the catecholamine site of the β1 -adrenoceptor with high affinity, but also exhibits agonist effects of its own at higher concentrations through a secondary, low-affinity β1 -adrenoceptor site or conformation. β-blocker affinities for this 'CGP 12177' site of the human β1 -adrenoceptor have thus far only been ch...

b 3 -adrenoceptors are involved in metabolism, gut relaxation, and vascular vasodilation. However, their existence and role in the human heart have not been documented. We investigated the effects of several b -adrenoceptor agonists and antagonists on the mechanical properties of ventricular endomyocardial biopsies. In the presence of nadolol, a b 1 and b 2 -adrenoceptor antagonist, isoprenalin...

Using the cannula inserting method, vasoconstrictor responses to 1-adrenoceptor agonists (noradrenaline [NA], phenylephrine [PE] and methoxamine [ME]) and effects of 1-adrenoceptor antagonists (WB4101, chloroethylclonidine [CEC] and BMY7378) were investigated in isolated and perfused rat common carotid arteries. The rank order of agonist potency and efficacy was NA PE ME. Either WB4101 or BYM73...

To determine which subtype of alpha1-adrenergic receptors plays a role in the regulation of blood pressure, with alpha1A-adrenergic receptor-mediated vasoconstriction in perfused hindlimb as a control, we compared the inhibitory effects of various alpha1-adrenergic receptor selective antagonists on the vasopressure responses to phenylephrine between the mean arterial pressure and hindlimb perfu...

PURPOSE Alpha1 (α1)-adrenoceptor antagonists are widely used to treat lower urinary tract symptoms. These drugs not only act on peripheral tissues, but also cross the blood-brain barrier and affect the central nervous system. Therefore, α1-adrenoceptor antagonists may enhance brain functions. In the present study, we investigated the effects of tamsulosin, an α1-adrenoceptor antagonist, on shor...

Since the introduction of 3 adrenoceptor antagonists into clinical practice approximately 30 years ago, these drugs have been regarded as being contraindicated in patients with severely depressed ventricular function because of the risk of precipitating haemodynamic deterioration. It may therefore seem both surprising and paradoxical that the idea of using 0 blockers as a primary therapy for co...

1. Hypertensive men treated with beta-blockers frequently complain of erectile dysfunction. The present study investigated the effects of two beta(1)-adrenoceptor-selective antagonists, namely nebivolol and metoprolol, on erectile function in hypertensive men. 2. Male out-patients (age range 40-55 years) with newly diagnosed or existing stage 1 essential hypertension (mean seated systolic blood...

Modulation of sacral spinal dorsal horn neurons by the ventrolateral PAG was studied by extracellular recording combined with microiontophoretic applications of alpha-adrenergic agonists or antagonists. Bicuculline (BIC, 15 ng) microinjected into the ventrolateral PAG produced a consistent inhibition of the responses of nociceptive dorsal horn neurons. After PAG-BIC applications, the total numb...