Fig. 4.30. Gating in single sodium channels: Patch clamp recording of unitary Na currents in a toe muscle of adult mouse during a voltage step from -80 to -40 mV. Cell-attached recording from a Cs-depolarized fiber. (A) Ten consecutive trials filtered at 3-KHz bandwidth. Two simultaneous channel openings have occurred in the first record; the patch may contain over 10 sodium channels. The dashed line indicates the current level when channels are all closed (background current). (B) The ensemble mean of 352 repetitions of the same protocol. T = 15 °C. (From Hille, 1992, as provided by J. B. Patlak; see also Patlak and Ortiz, 1986.).