Alpha-1 adrenergic receptors mediate adaptive effects in the heart and cardiac myocytes, and a myocyte survival pathway involving the alpha-1A receptor subtype and ERK activation exists in vitro. However, data in vivo are limited. Here we tested A61603 (N-[5-(4,5-dihydro-1H-imidazol-2-yl)-2-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl]methanesulfonamide), a selective imidazoline agonist for the al...

Introduction: Similarities in the memory impairment between Alzheimer patients and scopolamine treated animals have been reported. In the present study, the possible role of α-adrenergic receptors of the dorsal hippocampus on scopolamine state-dependent memory in adult male Wistar rats was evaluated. Methods: The animals were bilaterally implanted with chronic cannulae in the CA1 regions o...

The 2.4 A crystal structure of the beta(2)-adrenergic receptor (beta(2)AR) in complex with the high-affinity inverse agonist (-)-carazolol provides a detailed structural framework for the analysis of ligand recognition by adrenergic receptors. Insights into agonist binding and the corresponding conformational changes triggering G-protein coupled receptor (GPCR) activation mechanism are of speci...

PURPOSE The lacrimal gland secretes water, electrolytes, and protein into the tear film. Decreased secretion from the lacrimal gland can lead to dry eye syndromes with deleterious effects on vision. Protein kinase C (PKC)-alpha plays a major role in cholinergic- and alpha1-adrenergic-induced protein secretion from the lacrimal gland. This study was undertaken to determine whether activation of ...

Autophagy recently has been shown to be involved in normal hepatic function and in pathological conditions such as non-alcoholic fatty liver disease. Adrenergic signalling also is an important regulator of hepatic metabolism and function. However, currently little is known about the potential role of adrenergic signaling on hepatic autophagy, and whether the β-adrenergic receptor itself may be ...

A series of mutant avian beta-adrenergic receptors with progressively truncated carboxyl termini have been expressed in insect and mammalian cells. Removal of 18-124 amino acid residues caused multiple phenotypic changes in the receptor. Membranes from cells that expressed the truncated receptors displayed elevated basal (2- to 3-fold) and agonist-stimulated adenylylcyclase activities. Adenylyl...

In contrast to adrenaline, exogenously administered cholinergic agonist, carbachol have very little effect on the contractility of rat cardiac myocytes, unless its contractile has been increased by adrenergic agonist. This interaction between the muscarinic and adrenergic pathways has been suggested to be the major means by which muscarinic agonist alters adrenergic function. When the cardiac m...

Buckwalter, John B., Jessica C. Taylor, Jason J. Hamann, and Philip S. Clifford. Role of nitric oxide in exercise sympatholysis. J Appl Physiol 97: 417–423, 2004. First published March 12, 2004; 10.1152/japplphysiol.01181.2003.—The production of nitric oxide is the putative mechanism for the attenuation of sympathetic vasoconstriction (sympatholysis) in working muscles during exercise. We hypot...

Background—Muscle sympathetic vasoconstrictor nerve activity increases with age in healthy humans but does not result in an augmented forearm vasoconstrictor tone. We tested the hypothesis that this is due to a reduction in postjunctional -adrenergic responsiveness to endogenous norepinephrine (NE) release and determined whether this was specific to 1or 2-adrenergic receptors. Methods and Resul...

Black Americans have a reduced hypotensive response to the alpha2-adrenergic receptor agonist clonidine compared with whites, despite similar central sympathoinhibition. This reduced hypotensive response might be explained by greater postsynaptic vascular alpha2-adrenergic receptor vasoconstrictive response. However, clonidine has a low alpha2/alpha1 selectivity ratio. Therefore, to determine t...