Abstract
Chronic hypoxia impairs adrenergic responsiveness. A modulation of Gs and/or G1 protein alpha-subunits may be associated with the downregulation of the beta-adrenergic receptors previously found in chronic hypoxia. G protein gene expression and protein level and function in rat hearts exposed to a 30-day hypobaric chronic hypoxia were compared with control rat hearts. No change was observed in G alpha s mRNA levels in either right or left ventricles. In right ventricles, mRNA levels of G alpha i-2 increased by 40% (P < 0.05), but not in left ventricles. In both left and right ventricles, chronic hypoxia did not modify G alpha i-2 and G alpha s protein amounts, but significantly decreased functional activity of G alpha s. In conclusion, gene expression, protein levels of G alpha s and G alpha i-2, and activity of G alpha s do not change in parallel fashion with chronic hypoxia. In chronic hypoxic right ventricles, although the mRNA level of G alpha i-2 is increased, the protein level is unchanged. One potential mechanism of desensitization to catecholamines in chronic hypoxia appears to involve a decreased functional activity of G alpha s in spite of normal mRNA and protein levels.
Citations
Dec 22, 2000·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·F León-VelardeJ P Richalet
May 31, 2008·Journal of Applied Physiology·Wen YinJian-Ming Pei
May 17, 2001·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·W J Becker, J G Cannon
May 9, 2003·Journal of Applied Physiology·Markéta HrbasováPetr Svoboda
Oct 4, 2013·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·I Lindgren, J Altimiras
Nov 6, 2003·American Journal of Physiology. Cell Physiology·Jian-Ming PeiTak Ming Wong
Feb 10, 2004·Journal of Applied Physiology·Ganesh K Kumar, Jon B Klein
Jan 26, 2010·American Journal of Physiology. Heart and Circulatory Physiology·Yue GuanYi Zhang
Jan 6, 2005·Medicine and Science in Sports and Exercise·Xavier WooronsJean-Paul Richalet
Oct 12, 2010·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Jean-Paul RichaletJean-Claude Souberbielle
Feb 6, 2010·Journal of Applied Physiology·Yan CuiJian-Ming Pei
Oct 13, 2000·American Journal of Physiology. Cell Physiology·J M PeiT M Wong
May 25, 2007·Respiratory Physiology & Neurobiology·Fabrice Favret, Jean-Paul Richalet