Figure 6. Effect of C. rodentium induced colitis on the current–voltage relationship and the steady-state activation and inactivation of I_A and I_K at the height of infection (day 10) and on resolution (day 30).

A, correlation of the current–voltage relationship for I_A (upper left panel) and I_K (middle left panel) showing significantly decreased currents by C. rodentium colitis near the resting membrane potential. Upper and middle central panels illustrate the steady-state activation curves for I_A and I_K from control and infected animals. Means ±s.e.m. of normalized conductance (G/G_max) were plotted against membrane potential. Data were fitted using Boltzmann function, and continuous lines show best fits. The upper and middle right panels show the steady-state inactivation curves for both currents in neurons from C. rodentium infected animals and controls. The curves were obtained by plotting the normalized test current amplitudes against conditioning pre-pulse potentials. C. rodentium induced colitis caused a leftward shift in the steady-state inactivation curves for both I_A (upper right panel) and I_K (middle right panel). B, at day 30, C. rodentium induced colitis also significantly decreased I_A currents near the resting membrane potential (lower left panel). The steady-state activation kinetics of I_A was not altered (lower middle panel). However, the steady-state inactivation curve for I_A currents (lower right panel) in neurons from C. rodentium treated animals shifted to the left (hyperpolarizing shift) when compared to controls.