Cardiac α1-Adrenoceptors and Inotropy
ثبت نشده
چکیده
Cardiac α1-adrenoceptor stimulation elicits a positive inotropic effect because of myofilament Ca2+ sensitization with a small increase in Ca2+ transients predominantly mediated by α1B-adrenoceptors via the intracellular alkalinization and potential myosin light chain 2 phosphorylation. However, the α1-adrenoceptor– mediated inotropy exhibits a wide range of species-dependent variation. In addition, it displays remarkable regional and subtype-dependent variations among species. The signaling pathway for α1-adrenoceptor– mediated regulation is vulnerable being markedly influenced by experimental and pathophysiological conditions. Cardiac α1-adrenoceptors may have clinical relevance in that sympathomimetic amines including norepinephrine possess higher affinity to α1-adrenoceptors than β-adrenoceptors, and α1-adrenoceptors play a compensatory role in patients with heart failure. Modulation of cardiac α1-adrenoceptor–mediated signaling pathway could provide potential targets for the development of novel therapeutic strategy.
منابع مشابه
Cardiac α1-Adrenoceptors and Inotropy
Cardiac α1-adrenoceptor stimulation elicits a positive inotropic effect because of myofilament Ca2+ sensitization with a small increase in Ca2+ transients predominantly mediated by α1B-adrenoceptors via the intracellular alkalinization and potential myosin light chain 2 phosphorylation. However, the α1-adrenoceptor– mediated inotropy exhibits a wide range of species-dependent variation. In addi...
متن کاملCardiac α1-Adrenoceptors and Inotropy
Cardiac α1-adrenoceptor stimulation elicits a positive inotropic effect because of myofilament Ca2+ sensitization with a small increase in Ca2+ transients predominantly mediated by α1B-adrenoceptors via the intracellular alkalinization and potential myosin light chain 2 phosphorylation. However, the α1-adrenoceptor– mediated inotropy exhibits a wide range of species-dependent variation. In addi...
متن کاملCONTRACTIONS DUE TO α-ADRENOCEPTOR AGONISTS ARE MEDIATED BY α1-ADRENOCEPTORS IN RAT CAROTID ARTERY
Some large vessels have a mixed functional population of postjunctional α1- and α 2-adrenoceptors. The purpose of the work presented here was to investigate the population of postjunctional α -adrenoceptors in the rat isolated common carotid artelY Male Wi star rats were killed by overdose with pentobarbitone sodium, after which the left and right common carotid arteries were removed. Rings...
متن کاملSUBTYPES OF α1-ADRENOCEPTORS IN RABBIT SAPHENOUS VEIN
We investigated the a,-adrenoceptor subtypes of rabbit saphenous vein which has a mixed functional population of α1 and α2 -adrenoceptors. Lateral saphenous veins were obtained from male rabbits weighing 3.20-4 kg, which were killed by overdose with pentobarbitone sodium (i.v. injection). They were easily dissected out and placed in cold, oxygenated modified Krebs-Henselite solution (Krebs)...
متن کاملNuclear Compartmentalization of α1-Adrenergic Receptor Signaling in Adult Cardiac Myocytes
Although convention dictates that G protein-coupled receptors localize to and signal at the plasma membrane, accumulating evidence suggests that G protein-coupled receptors localize to and signal at intracellular membranes, most notably the nucleus. In fact, there is now significant evidence indicating that endogenous alpha-1 adrenergic receptors (α1-ARs) localize to and signal at the nuclei in...
متن کامل