Document Detail

A theoretical study on the role of Ca(2+)-activated K(+) channels in the regulation of hormone-induced Ca(2+) oscillations and their synchronization in adjacent cells.
MedLine Citation:
PMID:  22659037     Owner:  NLM     Status:  Publisher    
BACKGROUND: information. In many non-excitable cells hormone stimulation triggers repetitive oscillations of the intracellular Ca(2+) concentration, thought to be important in several cell functions. Although most of these cells respond to an elevation of the intracellular Ca(2+) concentration with a membrane hyperpolarization, due to the activation of Ca(2+)-activated K(+) channels, theoretical models do not usually consider the contribution of the membrane potential dynamics in defining the properties of the intracellular Ca(2+) concentration oscillations and their synchronization in adjacent, coupled cells. RESULTS: We developed a theoretical model of intracellular Ca(2+) oscillations that includes the dynamics of the membrane potential controlled by the cyclic activation of Ca(2+)-activated K(+) channels. We found that membrane potential oscillations determine an in-phase oscillating Ca(2+) influx that significantly affects the amplitude, duration and oscillatory frequency of the intracellular Ca(2+) concentration oscillations. Under specific levels of hormone stimulation Ca(2+)-activated K(+) channels are essential for establishing or inhibiting the intracellular Ca(2+) concentration oscillatory activity, as also suggested by some experimental findings. We also found that in electrically coupled cells displaying Ca(2+)-activated K(+) channels-induced membrane potential oscillations, the synchronization of intracellular Ca(2+) concentration oscillations in adjacent cells can occur in the complete absence of gap junction Ca(2+) or inositol trisphosphate diffusion, the simple electrical coupling being sufficient for synchronization. Finally, electrical coupling between adjacent cells was found to work in synergy with gap junction Ca(2+) permeability in the synchronization of intracellular Ca(2+) concentration oscillations, making it to occur at lower gap junction Ca(2+) permeabilities. CONCLUSIONS: Data from our model indicate that Ca(2+)-activated K(+) channel activity may be critical to establish important properties of the intracellular Ca(2+) concentration oscillations, and may help synchronize intracellular Ca(2+) concentration oscillations in electrically coupled cells. The model we propose here thus represents a third model of synchronization of intracellular Ca(2+) concentration oscillations in adjacent cells, based exclusively on the gap junction electrical coupling between cells displaying Ca(2+)-activated K(+) channel-induced membrane potential oscillations.
Luigi Catacuzzeno; Bernard Fioretti; Fabio Franciolini
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-5-30
Journal Detail:
Title:  Journal of theoretical biology     Volume:  -     ISSN:  1095-8541     ISO Abbreviation:  -     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-6-4     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376342     Medline TA:  J Theor Biol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier Ltd. All rights reserved.
Dipartimento di Biologia Cellulare e Ambientale, Universita' di Perugia, via Pascoli 1, I-06123 Perugia, Italy.
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