Ensemble noise and current relaxation analysis of K+ current in single isolated salivary acinar cells from rat |
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| Authors: | Y Maruyama A Nishiyama T Izumi N Hoshimiya O H Petersen |
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| Institution: | (1) Department of Physiology, Tohoku University School of Medicine, Seiryo-cho 2-1, Sendai, Japan;(2) R.I.A.E. Hokkaido University, Sapporo, Japan;(3) MRC Secretory Control Group, Physiological Laboratory, University of Liverpool, L69 3BX Liverpool, UK;(4) Present address: Department of Physiology, Faculty of Medicine, Tokyo University, Hongo 7-3-1, 113 Bunkyo-ku, Tokyo, Japan |
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| Abstract: | The K+ channel in rat parotid gland acinar cells were investigated by ensemble current noise analysis in single isolated cells employing the giga-seal whole cell current recording mode. Sets of 20–40 identical de- and hyperpolarization voltage steps were applied and the resultant current records were processed by computer to obtain the mean and the variance of the current. The time-course of the mean current could be fitted by the sum of two exponentials, suggesting a 3-state model. The simplest plausible hypothesis is a model with one open and two closed states. Assuming this model, the relationship between the variance ( 2) and the mean current (I) could be fitted by the function 2/I=i–I/N. The estimated single channeli/V-relations were similar to those taken from single channel current recordings, and the size of the population of channels per cell (N) was 76±26 (n=12). The validity of the model was tested by a successful simulation of the time-course of the variance. |
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| Keywords: | K+ channels Acinar cells Ensemble noise analysis Current relaxation Patch-clamp whole cell recording |
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