FIGURE 9.

Gating of N2E+G5R hemichannels. (A) A cell-attached record of a single N2E+G5R channel at a holding potential of −50 and +50 mV. The transitions at +50 correspond to V_j-gating, whereas those at negative potentials correspond to loop-gating events. The asterisk marks a loop-gating event, as judged by the slow time course of the transitions between the open and closed states. (B) The current/voltage relation of N2E+G5R recorded in an inside-out patch configuration. Leak current was not subtracted. Loop-gating transitions are observed more frequently at negative potentials, V_j-gating transitions at positive potentials. The open state of the channel rectifies inwardly. Records were obtained in bath and pipette solutions containing 88 mM NaCl, 1 mM KCl, 1 mM MgCl₂, 2 mM EDTA, 2 mM EGTA, and 10 mM HEPES, pH 7.6