In this study, the effects of nine alpha-1 adrenoceptor antagonists [prazosin, WB 4101 (WB), chloroethylclonidine (CEC), 5-methylurapidil (5-MU), BMY 7378 (BMY), MDL 73005EF (MDL73), MDL 72832 (MDL72), RS 17053 (RS) and SK&F 105854 (SKF)] were studied on contractile responses to phenylephrine (PE) of the endothelium-denuded dog aorta in vitro. All antagonists, except CEC, 5-MU and RS, produced ...

Studies proved that among all α1-adrenoceptors, cardiac myocytes functionally express only α1A- and α1B-subtype. Scientists indicated that α1A-subtype blockade might be beneficial in restoring normal heart rhythm. Therefore, we aimed to determine the role of α1-adrenoceptors subtypes (i.e., α1A and α1B) in antiarrhythmic effect of six structurally similar derivatives of 2-methoxyphenylpiperazin...

Catecholamines, either endogenous hormones or a variety of exogenous synthetic pharmacological agents, bind to adrenoceptors to mediate their ultimate clinical effects [21]. Since adrenoceptors mediate many cardiovascular responses, pharmacological stimulation and inhibition of adrenoceptors may be useful to the anaesthetist. Ahlquist described originally two adrenoceptor subtypes (alpha and be...

Emotionally arousing events are particularly well remembered. This effect is known to result from the release of stress hormones and activation of beta adrenoceptors in the amygdala. However, the underlying cellular mechanisms are not understood. Small conductance calcium-activated potassium (SK) channels are present at glutamatergic synapses where they limit synaptic transmission and plasticit...

Matrix metalloproteinase (MMP)-dependent shedding of heparin-binding epidermal growth factor (HB-EGF) and subsequent activation of the EGF receptor (EGFR) in the cardiovasculature is emerging as a unique mechanism signaling growth effects of diverse G protein–coupled receptors (GPCRs). Among these GPCRs are adrenoceptors and angiotensin receptors that contribute to the pathogenesis of hypertens...

BACKGROUND AND PURPOSE alpha(1)-Adrenoceptor agonists induce Ca(2+)-transients in endothelial cells (ECs) of arterioles. However, the presence of alpha(1)-adrenoceptors on arteriolar ECs has not been excluded, and the identity of alpha(1)-adrenoceptor subtypes in arterioles only has been inferred from pharmacology. Therefore, we determined which subtypes were expressed by vascular smooth muscle...

1. Responses of muscle strips from the stomach of the guinea-pig have been recorded. Sympathomimetic amines cause inhibitory, motor or biphasic responses.2. The motor components of the responses of the preparations were greatly enhanced by the removal of the mucosal layers.3. The inhibitory responses to isoprenaline, noradrenaline and phenylephrine were antagonized by propranolol or by sotalol....

We determined the binding affinity of tamsulosin, a selective α(1)-adrenoceptor antagonist, for human α(1)-adrenoceptor subtypes in comparison with those of other α(1)-adrenoceptor antagonists including silodosin, prazosin, 5-methylurapidil, terazosin, alfuzosin, nafopidil, urapidil and BMY7378. The association and dissociation kinetics of [(3)H]tamsulosin for recombinant human α(1)-adrenocepto...

INTRODUCTION α1-Adrenoceptors are considered critical for the regulation of prostatic smooth muscle tone. However, previous studies suggested further α1-adrenoceptor functions besides contraction. Here, we investigated whether α1-adrenoceptors in the human prostate may activate extracellular signal-regulated kinases (ERK1/2). METHODS Prostate tissues from patients undergoing radical prostatec...