[Current views on receptors for mediators of the autonomic nervous system of the heart].
Heart function reflects activity of the heart pacemaker cells. This basic function is permanently influenced by two practically antagonistic systems--sympathetic and parasympathetic systems. They control not only the force of contraction (influencing calcium channels), heart rate (via potassium channels), but also arterioventricular transduction (changing the threshold for ion channels opening by influencing the maximal negative level of the membrane potential). Last few years changed our view on autonomic receptor expression in the heart. It is assumed that the heart adrenoreceptors are represented by alpha 1, beta, and beta 2 subtypes. The expression of beta 3 subtype is still controversial, similarly the existence of other, fourth beta-adrenoreceptor subtype, putative beta 4, is uncertain. Moreover, the end of the twentieth century brought the correction of former idea about a single muscarinic receptor subtype (M2) in the heart. Functional correlates of these findings are also reviewed.
Myslivecek
J
J
Fyziologický ústav 1. LF UK, Praha. jmys@lf1.cuni.cz
D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D006321:Heart / Q000294:innervation* / Q000502:physiology; D006801:Humans; D011941:Receptors, Adrenergic / Q000502:physiology*; D011976:Receptors, Muscarinic / Q000502:physiology*
D011941:Receptors, Adrenergic; D011976:Receptors, Muscarinic