Fig 4. KDR channel.

(A) Voltage dependence of steady state activation (n_∞) of the modelled channel [21]. (B) The activation time constant (τ_n) of the channel: solid line = simulation (Sim.) and squares = experimental data for bladder small DRG neurons (Expt.) from [33]. (C) The currents (I_KDR) generated by the model (solid lines) and the corresponding currents reported in experiments (symbols, [7]) for bladder small DRG neurons using rectangular voltage clamp protocol. The holding potential was kept at −40 mV and test potentials of −20, −10 and 0 mV were applied for 300 ms. Experimental clamp currents: triangles (0 mV), squares = −10 mV and circles = −20 mV. (D) Steady state I-V relationship generated from model (solid line) and recorded from experiments (squares) for bladder small DRG neurons [33] by plotting the steady state current at end of each test potential. Protocol: Rectangular voltage clamp steps were applied from −80 to 10 mV in steps of 10 mV. The holding potential was −40 mV. Other model parameters: $\overline{g}=0.00072\text{S}/\text{cm}{}^2$, E_K = −84.7 mV, RMP = −53.5 mV, soma capacitance = 28 pF, soma diameter = 24 μm. The S values for model fits and their 5% threshold values (given in brackets) are: for voltage clamp currents at: 0 mV = 0.045 nA (0.029 nA), −10 mV = 0.029 nA (0.016 nA) & −20 mV = 0.031 nA (0.006 nA), and I-V curve = 0.043 nA (0.066 nA).