Synchronization of Ca2+ oscillations: a coupled oscillator-based mechanism in smooth muscle.
Entrained oscillations in Ca(2+) underlie many biological pacemaking phenomena. In this article, we review a long-range signaling mechanism in smooth muscle that results in global outcomes of local interactions. Our results are derived from studies of the following: (a) slow-wave depolarizations that underlie rhythmic contractions of gastric smooth muscle; and (b) membrane depolarizations that drive rhythmic contractions of lymphatic smooth muscle. The main feature of this signaling mechanism is a coupled oscillator-based synchronization of Ca(2+) oscillations across cells that drives membrane potential changes and causes coordinated contractions. The key elements of this mechanism are as follows: (a) the Ca(2+) release-refill cycle of endoplasmic reticulum Ca(2+) stores; (b) Ca(2+)-dependent modulation of membrane currents; (c) voltage-dependent modulation of Ca(2+) store release; and (d) cell-cell coupling through gap junctions or other mechanisms. In this mechanism, Ca(2+) stores alter the frequency of adjacent stores through voltage-dependent modulation of store release. This electrochemical coupling is many orders of magnitude stronger than the coupling through diffusion of Ca(2+) or inositol 1,4,5-trisphosphate, and thus provides an effective means of long-range signaling.
Imtiaz
Mohammad S
MS
Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada. mimtiaz@ucalgary.ca
von der Weid
Pierre-Yves
PY
van Helden
Dirk F
DF
D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D004563:Electrochemistry; D004721:Endoplasmic Reticulum / Q000502:physiology; D017629:Gap Junctions / Q000502:physiology; D006801:Humans; D042601:Lymphatic Vessels / Q000502:physiology; D008564:Membrane Potentials; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology*; D013270:Stomach / Q000502:physiology