title: Ca(2+)-activation kinetics modulate successive puff/spark amplitude, duration and inter-event-interval correlations in a Langevin model of stochastic Ca(2+) release.
abstract: Through theoretical analysis of the statistics of stochastic calcium (Ca(2+)) release (i.e., the amplitude, duration and inter-event interval of simulated Ca(2+) puffs and sparks), we show that a Langevin description of the collective gating of Ca(2+) channels may be a good approximation to the corresponding Markov chain model when the number of Ca(2+) channels per Ca(2+) release unit (CaRU) is in the physiological range. The Langevin description of stochastic Ca(2+) release facilitates our investigation of correlations between successive puff/spark amplitudes, durations and inter-spark intervals, and how such puff/spark statistics depend on the number of channels per release site and the kinetics of Ca(2+)-mediated inactivation of open channels. When Ca(2+) inactivation/de-inactivation rates are intermediate-i.e., the termination of Ca(2+) puff/sparks is caused by an increase in the number of inactivated channels-the correlation between successive puff/spark amplitudes is negative, while the correlations between puff/spark amplitudes and the duration of the preceding or subsequent inter-spark interval are positive. These correlations are significantly reduced or change signs when inactivation/de-inactivation rates are extreme (slow or fast) and puff/sparks terminate via stochastic attrition.
authors.affiliation: Department of Applied Science, The College of William and Mary, Williamsburg, VA 23187, United States. Electronic address: xwang06@email.wm.edu.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Applied Science, The College of William and Mary, Williamsburg, VA 23187, United States.
authors.forename: Yan
authors.initials: Y
authors.lastname: Hao
authors.affiliation: Department of Applied Science, The College of William and Mary, Williamsburg, VA 23187, United States.
authors.forename: Seth H
authors.initials: SH
authors.lastname: Weinberg
authors.affiliation: Department of Applied Science, The College of William and Mary, Williamsburg, VA 23187, United States.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Smith
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology*; D008390:Markov Chains; D008962:Models, Theoretical
chemical_list: D015220:Calcium Channels
keywords: Ca(2+) puffs; Ca(2+) sparks; Langevin equation; Markov chain