The beta-adrenoceptor agonist, isoprenaline, elicits vasodilation and tachycardia in anesthetized rats via activation of propranolol-sensitive beta1- and beta2-adrenoceptors and also by propranolol-insensitive beta1- and beta3-adrenoceptors. The aim of this study was to determine whether the relative contribution of propranolol-sensitive and -insensitive beta-adrenoceptors to the changes in hea...

These experiments investigated the role of the alpha(2)-adrenoceptors of the basolateral nucleus of the amygdala (BLA) in modulating the retention of inhibitory avoidance (IA). In Experiment 1, male Sprague Dawley rats implanted with bilateral cannulae in the BLA received microinfusions of a selective alpha(2)-adrenoceptor antagonist idazoxan 20 min either before or immediately after training. ...

In infant rats, administration of the alpha2 adrenoceptor agonist clonidine simultaneously evokes ultrasound production and bradycardia. In this study the authors examined in 8-day-old rats whether these 2 responses to clonidine are causally related. In Experiment 1 pups were pretreated with saline or prenalterol (0.1 or 1.0 mg/kg), a beta1 adrenoceptor agonist that increases cardiac rate, foll...

Recent evidence suggests that the quinazoline-based 1-adrenoceptor antagonists, doxazosin and terazosin, exhibit a potent apoptotic effect against prostate tumor epithelial cells, whereas tamsulosin, a sulfonamide-based 1-adrenoceptor antagonist, was ineffective in inducing a similar apoptotic effect against prostate cells (Cancer Res., 60: 4550–4555, 2000). In this study, to identify the preci...

It has been suggested that there is a link between epinephrine synthesis and the development of β2-adrenoceptor-mediated effects, but it remains to be determined whether this development is triggered by epinephrine. The aim of this study was to characterize β-adrenoceptor-mediated relaxation and facilitation of norepinephrine release in the aorta of phenylethanolamine-N-methyltransferase-knocko...

It has been suggested that there is a link between epinephrine synthesis and the development of b2-adrenoceptor–mediated effects, but it remains to be determined whether this development is triggered by epinephrine. The aim of this study was to characterize b-adrenoceptor–mediated relaxation and facilitation of norepinephrine release in the aorta of phenylethanolamine-Nmethyltransferase–knockou...

These experiments investigated the role of the 2-adrenoceptors of the basolateral nucleus of the amygdala (BLA) in modulating the retention of inhibitory avoidance (IA). In Experiment 1, male Sprague Dawley rats implanted with bilateral cannulae in the BLA received microinfusions of a selective 2-adrenoceptor antagonist idazoxan 20 min either before or immediately after training. Retention was ...

The aim of the present study was to investigate the in vitro effects of the short-acting β2-adrenoceptor agonist salbutamol and the long-acting β2-adrenoceptor agonist salmeterol on hypoxia-induced rat diaphragm force reduction. In vitro diaphragm twitch force (Pt) and maximal tetanic force (Po) of isolated diaphragm muscle strips were measured for 90 min during hyperoxia (tissue bath [Formula:...