Beta 3-adrenoceptors in the cardiovascular system

Abstract

The sympathetic system is central in the understanding of numerous physiological and physiopathological phenomena. During the last decade, the characterization of a new β-adrenoceptor subtype, β₃, in addition to β₁ and β₂-adrenoceptor in the cardiovascular system has changed the view of the roles of the sympathetic system. In heart, β₃-adrenoceptor stimulation produce an opposite effect to that induced by β₁ and β₂-adrenoceptors suggesting that in normal heart, the negative inotropic effect induced by the β₃-adrenergic stimulation might play a role of a “safety-valve” during intense adrenergic stimulation. In vessels, all β-adrenoceptors subtypes, β₁, β₂ and β₃, mediate a vasodilation. As β₃-adrenoceptors are activated at higher concentrations of catecholamines than β₁ and β₂-adrenoceptors, they could play the roll of a receptor reserve. β₃-adrenoceptors are overexpressed in heart failure and hypertension and could constitute a new therapeutic target. In addition, the efficiency of some β-blockers such as nebivolol could result from an action on β₃-adrenoceptors.