BACKGROUND Contrary to beta(1)- and beta(2)-adrenoceptors, beta(3)-adrenoceptors mediate a negative inotropic effect in human ventricular muscle. To assess their functional role in heart failure, our purpose was to compare the expression and contractile effect of beta(3)-adrenoceptors in nonfailing and failing human hearts. METHODS AND RESULTS We analyzed left ventricular samples from 29 fail...

Neuronal circuit plasticity during development is fundamental for precise network formation. Pioneering studies of the developmental visual cortex indicated that noradrenaline (NA) is crucial for ocular dominance plasticity during the critical period in the visual cortex. Recent research demonstrated tonotopic map formation by NA during the critical period in the auditory system, indicating tha...

The nucleus tractus solitarii (NTS) in the dorsomedial medulla comprises a wide range of neuropeptides and biogenic amines. Several of them are related to mechanisms of central blood pressure control. Angiotensin II (Ang II), neuropeptide Y (NPY) and noradrenaline (NA) are found in the NTS cells, as well as their receptors. Based on this observation we have evaluated the modulatory effect of th...

Interactions between neuronal responses mediated by opiate receptors and by alpha 2-adrenoceptors were characterized in the amygdala. Extracellular single-unit recordings and microiontophoresis were performed using five-barrel microelectrodes in chloral hydrate-anesthetized rats. A subpopulation of amygdaloid cells displayed inhibitory responses to morphine or D-Ala,D-Leu-enkephalin; antagonist...

Three distinct genes encode α1-adrenoceptors. Although homodimers of each subtype have been reported, certain but not all combinations of heterodimers of the α1-adrenoceptors appear to form. Key studies in this field are reviewed and the approaches that have been applied to monitoring the selectivity and the basis of α1-adrenoceptor dimerization are discussed. Introduction GPCRs (G-protein-coup...

To the Editor:—I read with interest the study about the effect of a-2 adrenergic agonists on the spinal pial microcirculation in dogs. Using an in vivo technique, the authors observed a significant constriction of both pial arterioles and venules after topical application of clonidine or dexmedetomidine. They suggested that a-2 agonists might be superior to epinephrine or phenylephrine as local...

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...

Fiduxosin is a new 1-adrenoceptor antagonist targeted for the treatment of symptomatic benign prostatic hyperplasia. The purpose of this study was to determine and compare the potencies of the 1-adrenoceptor antagonists terazosin, doxazosin, tamsulosin, and fiduxosin, based on relationships between plasma drug concentrations and blockade of phenylephrine (PE)-induced intraurethral (IUP) and mea...

The effects of sympathomimetic amines on Ca transients and isometric contractions were assessed in isolated rabbit papillary muscles in which multiple superficial cells had been microinjected with the calcium-sensitive bioluminescent protein aequorin. In the presence of /3-adrenoceptor blockade, the a-receptor agonist phenylephrine increased both the amplitude of the aequorin signals and the fo...