Stress and cardiac beta adrenoceptors

Abstract

Most modern theories about stress recognize that although stress is not a disease, it may be the trigger for the majority of diseases when allostatic overload has been generated. During stress, the glucocorticoids and catecholamines play a key role in the regulation of physiological parameters and homeostasis during stress. In the heart, positive chronotropic, inotropic, and lusitropic responses to catecholamines are mediated by various subtypes of adrenergic receptors (β-ARs), mainly β1- and β2-adrenergic receptors. β-ARs also control cardiomyocyte growth and death, thus contributing to cardiac remodelling. The structural basis of each β-AR subtype, as well as their signalling pathways, and adaptive responses to stress are discussed. The participation of β3- and putative β4-ARs in the control of cardiac function is also discussed, with emphasis on low affinity β-AR isoforms and the role they play in the response to the catecholamines under stress. The changes in β-AR signalling under pathogenic conditions as well as under stress are reviewed.