Figure 5.

Channel kinetic estimation using linear (Ohmic) passive membrane kinetics can cause substantial errors in cell types with large ionic concentration gradients. Effect of GHK leak currents on simulated voltage-clamp of mammalian voltage-gated K⁺ current, Kv4 (A) and K⁺ current from the Hodgkin-Huxley model (B) The ionic concentration in (A) is the same as that in Figure 2. The ionic concentration in (B) is adapted from Table 2 in Hodgkin (1951), which listed the approximate intra- and extracellular concentration of K⁺, Na⁺, and Cl⁻ in Loligo axons (Hodgkin, 1951). Furthermore, E_rest and membrane resistance values for the squid model were set to NEURON default values. Note that both the mammalian and squid axon K⁺ currents were calculated by multiplying the gating variables with a GHK current component. Simulations using Ohmic and GHK leak currents are colored blue and orange, respectively. The initial fast transient is the capacitive current.