(a)
(b)
(c)
(d)
Figure 3: Effects of MK-801, NBQX, DL-AP3, or APDC pretreatment in the periphery on ES-induced PWT reduction. (a) In rats with L5 DR, an i.pl. injection of MK-801 (20 nM) administered immediately before the ES of L5 SN (L5 SN-ES) into the midpoint of the L4 plantar dermatome resulted in a significant increase in ES-induced decreased PWTs compared with vehicle-treated controls. (b) An i.pl. NBQX (100 nM) injection administered immediately prior to the ES produced no significant difference in ES-induced decreased PWTs from vehicle-treated controls. (c and d) Animals administered an i.pl. injection of DL-AP3 (70 nM) or APDC (20 nM) immediately prior to the ES exhibited a significant increase in ES-induced decreased PWTs compared with vehicle-treated controls. The abbreviations B and D are defined in Figure 2. The values in parentheses indicate the number of animals used. The error bars represent the SEM. versus vehicle groups. # versus baseline.