Heart ventricles specific stress-induced changes in β-adrenoceptors and muscarinic receptors

Gen Physiol Biophys. 2014;33(3):357-64. doi: 10.4149/gpb_2014002. Epub 2014 Jun 26.

Abstract

The left and right ventricles fulfill different role in heart function. Here we compare chamber specific changes in local catecholamine concentrations; gene expression and the receptor protein amount of all three β-adrenoceptors (β-AR) in rat right heart ventricles exposed to acute (1 session) and repeated (7 sessions) immobilization stress (IMMO) vs. previously observed changes in left ventricles. Density of muscarinic receptors as main cardio-inhibitive receptors was also measured. In the right ventricles, noradrenaline and adrenaline were increased. No β1-AR changes were observed, in spite of the increased sympathetic activity. On the other hand, we have found a decrease of β2-AR gene expression (reduction to 30%) after 7 IMMO and protein (to 59%) after 1 IMMO. β3-AR gene expression was increased after 7 IMMO. Muscarinic receptor density was not changed. When comparing correlation in left and right ventricles, there was strong correlation between adrenaline and β2-AR gene expression, protein and β3-AR gene expression in the left ventricles while only correlation between adrenaline and β2-AR mRNA and protein in the right ventricles was found. Our results show that maintenance of cardiac homeostasis under stress conditions are to a great extent achieved by a balance between different receptors and also by a balanced receptor changes in left vs. right ventricles. Taken together, decrease of cardio-stimulating β2-AR represents a new important mechanism by which β2-AR contributes to the heart physiology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Catecholamines / biosynthesis
  • Epinephrine / biosynthesis
  • Gene Expression Profiling
  • Gene Expression Regulation
  • Heart Ventricles / metabolism*
  • Heart Ventricles / physiopathology*
  • Male
  • Norepinephrine / biosynthesis
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, beta / metabolism*
  • Receptors, Muscarinic / metabolism*
  • Restraint, Physical
  • Stress, Physiological*

Substances

  • Catecholamines
  • RNA, Messenger
  • Receptors, Adrenergic, beta
  • Receptors, Muscarinic
  • Norepinephrine
  • Epinephrine