Fig. 8.

Membrane currents from hemichannels composed of Cx46 and G46V exhibit distinct voltage-dependent properties. A–C: representative families of current traces recorded from single oocytes injected with similar amounts of cRNA for Cx46 (A), G46V (B), or wild-type Cx50 (C) in NaCl solution containing 0.7 mM [Ca²⁺]_o and 1 mM [Mg²⁺]_o. The oocytes were held at −80 mV between pulse sequences. Voltage-clamp steps were applied to voltages between −80 mV and 30 mV in increments of 10 mV. The data were not corrected for leakage current. Dashed line represents zero current. D: quasi-steady-state I-V relationships for Cx46 (▲, n = 3), G46V (○, n = 4), and wild-type Cx50 (□, n = 5) were determined by measuring the current at the end of the test pulse and plotting it as a function of pulse potential. hCx50, human Cx50; rCx46, rat Cx46. E: isochronal conductance-voltage relationships for Cx46 (▲, n = 3) and G46V (○, n = 4). Initial amplitude of tail currents were measured at −80 mV after 20-s pulses to different potentials and then normalized to the amplitude of the tail current after a voltage-clamp pulse to +30 mV.