Figure 5

CFA injection suppresses voltage-gated potassium currents. Currents were measured at different holding potentials. For total voltage-gated potassium current (I_Total), the membrane potential was held at -100 mV and voltage steps were from -50 to +90 mV with10-mV increments and 400 ms duration. For sustained voltage-gated potassium current (I_K), the membrane potential was held at -50 mV and the voltage steps were the same as above. Currents generated by these two protocols were subtracted to produce I_A. (A) Examples of total K_V currents recorded from NS (top) and CFA-treated rats (bottom). (B) Examples of I_K recorded from NS (top) and CFA-treated rats (bottom). (C) Examples of I_A recorded from NS (top) and CFA-treated rats (bottom). The peak I_Total (D), I_K (E) and I_A (F) versus voltages (I-V) were plotted from cells acutely dissociated from rats treated with NS or CFA. Bar graphs showed the mean peak I_Total (G), I_K (H), and I_K (I) densities from NS and CFA-treated rats. The current density (pA/pF) was calculated by dividing the current amplitude by cell membrane capacitance. CFA injection caused a significant reduction of I_Total (G, *p < 0.05, compared with NS, two sample t-Test). The I_K density was significantly reduced (H, *p < 0.05, compared with NS, two sample t-Test) while the I_A was not altered significantly after CFA injection (I).