Fig. 3.  In vitro and  in vivo applications of vitamin B1 suppress hyperexcitability of the dorsal root ganglion (DRG) neuron after chronic compression of DRG (CCD).  A : Effects on resting membrane potentials (RMP).  B : Effects on the current needed to reach action potential (AP) threshold.  C : Effects on repetitive firing evoked by a 1-s depolarizing pulse at 2.5 × the threshold current.  D : Percentage of tested DRG neurons displaying spontaneous activity (SA). *  P < 0.05, **  P < 0.01 indicate significant differences compared to the sham control group. #  P < 0.05, ##  P < 0.01 indicate significant differences between corresponding groups in the presence and absence of vitamin B1. The numbers of cells tested in each group are shown in parentheses. B1 was applied  in vitro at 0.1, 1, and 10 mm, respectively, and  in vivo repetitive intraperitoneal injection (66 mg/kg, once daily consecutive for 10–14 days).