Role of α2-Adrenoceptor Subtypes in Suppression of L-Type Ca2+ Current in Mouse Cardiac Myocytes |
| |
| Authors: | Edward V. Evdokimovskii Ryounghoon Jeon Sungjo Park Oleg Y. Pimenov Alexey E. Alekseev |
| |
| Affiliation: | 1.Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Institutskaya 3, 142290 Pushchino, Russia; (E.V.E.); (O.Y.P.);2.Department of Cardiovascular Medicine, Center for Regenerative Medicine, Mayo Clinic, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA; (R.J.); (S.P.) |
| |
| Abstract: | Sarcolemmal α2 adrenoceptors (α2-AR), represented by α2A, α2B and α2C isoforms, can safeguard cardiac muscle under sympathoadrenergic surge by governing Ca2+ handling and contractility of cardiomyocytes. Cardiomyocyte-specific targeting of α2-AR would provide cardiac muscle-delimited stress control and enhance the efficacy of cardiac malfunction treatments. However, little is known about the specific contribution of the α2-AR subtypes in modulating cardiomyocyte functions. Herein, we analyzed the expression profile of α2A, α2B and α2C subtypes in mouse ventricle and conducted electrophysiological antagonist assay evaluating the contribution of these isoforms to the suppression of L-type Ca2+ current (ICaL). Patch-clamp electro-pharmacological studies revealed that the α2-agonist-induced suppression of ICaL involves mainly the α2C, to a lesser extent the α2B, and not the α2A isoforms. RT-qPCR evaluation revealed the presence of adra2b and adra2c (α2B and α2C isoform genes, respectively), but was unable to identify the expression of adra2a (α2A isoform gene) in the mouse left ventricle. Immunoblotting confirmed the presence only of the α2B and the α2C proteins in this tissue. The identified α2-AR isoform-linked regulation of ICaL in the mouse ventricle provides an important molecular substrate for the cardioprotective targeting. |
| |
| Keywords: | G-protein coupled receptors left ventricle cell signaling guanabenz BRL 44408 ARC 239 JP 1302 |
|
|
