introduction the compounds known as β-adrenergic agonists (β-aa) are organic molecules that have the ability to bind to β-adrenergic receptors (β-ar) and start biochemical reactions that will result in increase of accretion of skeletal muscle and reduction in accretion of fat. the anabolic responses to β-aa are temporary, with a peak time occurring during the first 14 days, after which there is...

Alzheimer disease features amyloid-β (Aβ) peptide deposition in brain and blood vessels and is associated with hypertension. Aβ peptide can cause vasoconstriction and endothelial dysfunction. We observed that Aβ peptides exert a chronotropic effect in neonatal cardiomyocytes, similar to α1-adrenergic receptor autoantibodies that we described earlier. Recently, it was shown that α1-adrenergic re...

OBJECTIVE Severe congestive heart failure is associated with autonomic imbalance consisting of an increased sympathetic and decreased parasympathetic activity. In the present study, we investigated the influence of alterations in autonomic balance on cardiovascular function in 11 swine with left ventricular (LV) dysfunction produced by a 2- to 3-week-old myocardial infarction (MI). METHODS Sw...

The adenylate cyclase-coupled &-adrenergic receptor of the frog erythrocyte has served as a useful model system for elucidating the mechanisms of catecholamine-induced desensitization. In this system, it has been previously demonstrated that agonist-induced refractoriness is associated with sequestration of the @adrenergic receptors in vesicles away from the cell surface and from their effector...

Here we investigate how ß-adrenergic stimulation of the heart alters regulation of ryanodine receptors (RyRs) by intracellular Ca(2+) and Mg(2+) and the role of these changes in SR Ca(2+) release. RyRs were isolated from rat hearts, perfused in a Langendorff apparatus for 5 min and subject to 1 min perfusion with 1 µM isoproterenol or without (control) and snap frozen in liquid N2 to capture th...

BACKGROUND Previous studies from our laboratory showed cyclic increases in tissue cAMP during a multiple-cycle preconditioning (PC) protocol, followed by attenuated cAMP accumulation during sustained ischemia. The aim of this study was to determine whether ischemia-induced activation of the beta-adrenergic signaling pathway could act as a trigger in eliciting protection. METHODS AND RESULTS I...

Vascular smooth muscle sensitivity to catecholamine-induced contraction is increased after catecholamine depletion by chemical sympathectomy and decreased after exogenous catecholamine administration. To investigate the role of the vascular o-adrenergic receptor in these alterations, we used the a-1 selective radioligand, (H)-WB-4101, [phenoxy-3-H(JV)]-(2-(2,6-dimethoxyphenoxyethyl)aminomethyl-...

We ligated the left anterior descending coronary artery for 1 or 2 h in 31 purebred beagles. We did not detect any changes in beta-adrenergic receptor density or affinity when normal and ischemic zones were compared, either in the subendocardium or in the subepicardium. In the ischemic zones, there was a significant decline in all measures of adenylate cyclase activity, including activity media...

Adrenergic receptors are pharmacologically classified into the receptor types 1, 2, 1, 2, and 3. Structural differences and varying affinities in radioligand binding studies lead to a further classification of 1and 2-receptors into subtypes which are termed 1A (formerly 1C), 1B, and 1D (formerly 1AD), and 2AD, 2B, and 2C, respectively. mRNA expression of all but one -adrenergic receptor subtype...

Because of the central role of adrenergic mechanisms in the expression of crucial genes during brown adipocyte differentiation, we examined the activation (phosphorylation) of CREB (cAMP-response-element-binding protein) in mouse brown adipocytes in primary culture. We found that noradrenaline ('norepinephrine') stimulated CREB phosphorylation rapidly (maximum effect in < or =5 min with slow de...