Domain model for Ca2(+)-inactivation of Ca2+ channels at low channel density

A. Sherman, J. Keizer, J. Rinzel

Research output: Contribution to journalArticlepeer-review

Abstract

The "shell" model for Ca2(+)-inactivation of Ca2+ channels is based on the accumulation of Ca2+ in a macroscopic shell beneath the plasma membrane. The shell is filled by Ca2+ entering through open channels, with the elevated Ca2+ concentration inactivating both open and closed channels at a rate determined by how fast the shell is filled. In cells with low channel density, the high concentration Ca2+ "shell" degenerates into a collection of nonoverlapping "domains" localized near open channels. These domains form rapidly when channels open and disappear rapidly when channels close. We use this idea to develop a "domain" model for Ca2(+)-inactivation of Ca2+ channels. In this model the kinetics of formation of an inactivated state resulting from Ca2+ binding to open channels determines the inactivation rate, a mechanism identical with that which explains single-channel recordings on rabbit-mesenteric artery Ca2+ channels (Huang Y., J. M. Quayle, J. F. Worley, N. B. Standen, and M. T. Nelson. 1989. Biophys. J. 56:1023–1028). We show that the model correctly predicts five important features of the whole-cell Ca2(+)-inactivation for mouse pancreatic beta-cells (Plants, T. D. 1988. J. Physiol. 404:731–747) and that Ca2(+)-inactivation has only minor effects on the bursting electrical activity of these cells.

Original languageEnglish (US)
Pages (from-to)985-995
Number of pages11
JournalBiophysical journal
Volume58
Issue number4
DOIs
StatePublished - 1990

ASJC Scopus subject areas

  • Biophysics

Fingerprint Dive into the research topics of 'Domain model for Ca2(+)-inactivation of Ca2+ channels at low channel density'. Together they form a unique fingerprint.

Cite this