Beta 2-adrenoceptor-mediated intrinsic sympathomimetic activity of carteolol: an in vivo study.

The intrinsic sympathomimetic activity (ISA) of a beta-adrenoceptor blocker can be mediated by beta(1)- or beta(2)-adrenoceptors. The aim of this study was to characterize the ISA of the beta-adrenoceptor blocker carteolol in healthy volunteers. Two approaches were employed.

Cardiac beta-adrenoceptors in chronic uremia: studies in humans and rats.

Objectives: The purpose of this study was to elucidate whether cardiac beta-adrenergic effects may be blunted in patients on maintenance hemodialysis (HD) and may help to explain autonomic dysfunction.

Background: Patients on HD often suffer from autonomic dysfunction.

Methods: We investigated the cardiovascular response of five HD patients (age: 46.

Human cardiac beta1- or beta2-adrenergic receptor stimulation and the negative chronotropic effect of low-dose pirenzepine.

Objectives: The M1-muscarinic receptor antagonist pirenzepine in low doses (<1 mg intravenously) decreases heart rate. We investigated whether these effects of pirenzepine differ in volunteers with activated cardiac beta1-adrenergic receptors versus activated cardiac beta2-adrenergic receptors.

Methods: In 17 male volunteers (25 +/- 1 years) we studied effects of pirenzepine infusion (0.

Cardiac effects of beta-adrenoceptor antagonists with intrinsic sympathomimetic activity in humans: beta1- and/or beta2-adrenoceptor mediated?

The aim of this study was to find out whether cardiac responses to the beta-adrenoceptor antagonists with intrinsic sympathomimetic activity (ISA) xamoterol and celiprolol are mediated by cardiac beta1- or beta2-adrenoceptors or both. For this purpose we assessed, in six healthy male volunteers, the effects of xamoterol (100 and 200 mg, p.o.

Terbutaline-induced desensitization of human cardiac beta 2-adrenoceptor-mediated positive inotropic effects: attenuation by ketotifen.

Background: In patients with chronic heart failure cardiac beta 1-adrenoceptors are desensitized whereas beta 2-adrenoceptors are only marginally affected. The mechanism underlying this differential regulation is not known.

Objectives: To find out whether or not human cardiac beta 2-adrenoceptors might be 'resistant' to agonist-induced desensitization and whether or not the antiallergic drug ketotifen might attenuate possible desensitization.