Figure 5. Effects of C. rodentium induced colitis on isolated voltage gated K_v currents.

A, representative voltage clamp traces showing outward voltage gated K⁺ current families separated biophysically by manipulating the holding potential. Currents were generated using a 10 mV voltage step protocol (illustrated in inset) from −90 mV to +50 mV. At holding potential of −100 mV (left), two currents were evident, a transient inactivating A-type current (I_A) and sustained non-inactivating I_K type currents. At a holding membrane potential of −60 mV, I_A current was significantly inactivated such that only the sustained component I_K is elicited (middle) and subtraction of the sustained from the total current yielded I_A (right). B, summary of peak current density for I_A and I_K respectively. Current densities were obtained by normalizing the measured amplitudes of the peak transient components of the isolated currents to the cell capacitance. At the height of inflammation (day 10), C. rodentium induced colitis caused significant suppression of both I_A and I_K current densities (filled bar) compared to controls (open bar). C, following resolution of infection (day 30), the reduction in I_A current density was sustained in neurons from C. rodentium infected animals (filled bar) compared to controls (open bar). There was no significant difference in I_K current density between the two groups of neurons. Data are means ±s.e.m. *P < 0.05.