Fluctuations in ion channel gating currents. Analysis of nonstationary shot noise.
Conti and Stühmer (1989. Eur. Biophys. J. 17:53-59) have measured the nonstationary shot noise in the gating current of a population of sodium channels. Here we present expressions for the autocovariance and variance of such noise from general Markov models of channel kinetics, based on the theoretical work of E. Frehland. We compare the predictions of the independent, two-state gating model used by Conti and Stühmer with a six-state model of sodium channel activation based on the work of Armstrong and Gilly (1979. J. Gen. Physiol. 74:691-711). We find that Conti and Stühmer's experiment would not be able to distinguish between these schemes. We describe experimental conditions under which better model discrimination would be possible.
Crouzy
S C
SC
Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510.
Sigworth
F J
FJ
D000704:Analysis of Variance; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D004563:Electrochemistry; D015640:Ion Channel Gating / Q000502:physiology*; D007700:Kinetics; D008954:Models, Biological; D015222:Sodium Channels / Q000378:metabolism
D015222:Sodium Channels