Figure 6.

Taurine effect on junctional conductance. Exposure to 40 mM taurine had no significant effect on the voltage sensitivity of the junctional currents recorded over the range of ±80 mV, although there was a slight current reduction at negative junctional voltages. The data (n=4 for each condition) were fit by the Boltzmann equation: G_jss = { (G_jmax – G_jmin ) / ( 1 + exp [A ( V_j –V_o ) ] } + G_jmin where G_jmax (normalized to unity) is the maximum conductance, G_jmin is the residual conductance at large values of V_j, and V_o is the V_j at which G_jss = (G_jmax–G_jmin)/2. The constant A (A=nq/kT) represents the voltage sensitivity in terms of gating charge as the equivalent number (n) of electron charges (q) moving through the membrane, k is the Boltzmann constant, and T is the absolute temperature. As shown in the inset, taurine had no significant effect on the junctional conductance between paired oocytes expressing this gap-junctional protein (p=0.5444 by Student’s t-test), and there were no significant differences in the values of A for taurine treated and control oocytes in either the positive or negative branches of the curves. These findings are a good indication that taurine does not affect Cx43 gap junctional channels.