Figure 4. Redox mechanisms of LA inhibition of T-current in DRG cells.

A. Representative traces show LA (gray trace) inhibition of baseline T-current (black solid trace) in an acutely dissociated DRG cell after application of NEM (black doted trace).

B. Time course from the same experiment depicted in panel A of this figure. NEM inhibited about 50% of the peak baseline T-current. When 1 mM LA was applied after NEM treatment, it induced only a small inhibition (about 10 %) of the remaining inward current. Note that the inhibitory effect of NEM on peak T-current had a slower time course than did that of LA (Fig. 1B). The gray horizontal bar indicates the time of LA application; black horizontal line indicates the time of NEM application.

C. Representative traces in gray show inhibition of baseline T-current (black traces) in different DRG cells. In both experiments, 1 mM LA was applied in the bath. Top panel shows the effect of LA on T-current in a cell where 1 mM DTNB was included in the internal solution; the bottom panel shows the effect of the same concentration of LA when internal solution was supplemented with 1 mM MTSET.

Bars indicate calibration.

D. Histogram represents the average effect of separate bath applications of 1 mM LA on T- currents in DRG cells with control internal solution (left panel), and with internal solution containing either 1 mM DTNB (middle panel) or 1 mM MTSET (right panel). The average peak T-current inhibition was 46 ± 6% in control, 56 ± 3% with DTNB, and 51 ± 10% with MTSET. Vertical lines are ± SEM of multiple determinations. Number of cells in each experiment is indicated in parentheses. n.s.= not significant (p > 0.05).