Genesis and regulation of the heart automaticity

ME Mangoni, J Nargeot - Physiological reviews, 2008 - journals.physiology.org
ME Mangoni, J Nargeot
Physiological reviews, 2008journals.physiology.org
The heart automaticity is a fundamental physiological function in higher organisms. The
spontaneous activity is initiated by specialized populations of cardiac cells generating
periodical electrical oscillations. The exact cascade of steps initiating the pacemaker cycle in
automatic cells has not yet been entirely elucidated. Nevertheless, ion channels and
intracellular Ca2+ signaling are necessary for the proper setting of the pacemaker
mechanism. Here, we review the current knowledge on the cellular mechanisms underlying …
The heart automaticity is a fundamental physiological function in higher organisms. The spontaneous activity is initiated by specialized populations of cardiac cells generating periodical electrical oscillations. The exact cascade of steps initiating the pacemaker cycle in automatic cells has not yet been entirely elucidated. Nevertheless, ion channels and intracellular Ca2+ signaling are necessary for the proper setting of the pacemaker mechanism. Here, we review the current knowledge on the cellular mechanisms underlying the generation and regulation of cardiac automaticity. We discuss evidence on the functional role of different families of ion channels in cardiac pacemaking and review recent results obtained on genetically engineered mouse strains displaying dysfunction in heart automaticity. Beside ion channels, intracellular Ca2+ release has been indicated as an important mechanism for promoting automaticity at rest as well as for acceleration of the heart rate under sympathetic nerve input. The potential links between the activity of ion channels and Ca2+ release will be discussed with the aim to propose an integrated framework of the mechanism of automaticity.
American Physiological Society