Fig. 5. Effects of vitamin B1 on the tetrodotoxin-resistant (TTX-R) Na+current densities and properties of the small dorsal root ganglion (DRG) neurons after chronic compression of DRG (CCD). A : Representative TTX-R Na+current traces recorded in small neurons from sham, CCD, and CCD with in vitro perfusion or in vivo intraperitoneal injection of vitamin B1. B–E : Effects of in vitro and in vivo application of B1 on the density ( B ), current-voltage (I-V) relationship ( C ), activation ( D ), and steady-state inactivation ( E ) of TTX-R Na+currents of the small DRG neurons after CCD treatment. In B : * P < 0.05 indicates significant differences compared with the sham-operated control group. # P < 0.05 indicates significant differences compared with the CCD group. The current I-V relationship ( C ) and activation ( D ) were not altered by CCD and B1 treatment. The current inactivation curve ( E ) was left-shifted (hyperpolarized) by CCD and corrected by in vitro application of B1. The numbers of cells tested in each group are shown in parentheses.