Figure 3.
Kinetics of inactivation for heterotypic Cx43/Cx40 gap junctions. (A) Junctional current (Ij) decay time constants (τ) for a Cx43/Cx40 heterotypic cell pair when Vj = +120 mV relative to the Cx43 or Cx40 expressing cell. The inactivation rates were dramatically faster and the steady-state open probabilities were significantly (Popen) lower when Vj was positive on the Cx43-side of the gap junction. (B) The Vj-dependent inactivation (Kon) rates as determined by the equation Kon = (1-Popen)/τ when Vj was positive on the Cx43-side of the junction. (C) The same Kon calculation when Vj was positive on the Cx40 side of the heterotypic gap junction. (D) The first-order inactivation rates for the Cx43 and Cx40 Vj positive heterotypic gap junction are plotted relative to each other. The numbers of experiments (n) are indicated next to the symbol.