Fig. (2) Intradermal injection of CAP (2 h) enhanced the sensitization of C fibers induced by antidromic ES, while minocycline pretreatment completely blocked the enhancement induced by CAP. A. Representative traces showed the firing of a single fiber at baseline, 0, 5, and 15 min after antidromic ES of dorsal roots. Upper panel: the real- time histogram showing the spike frequency of the fiber with von Frey stimulation. Lower panel: original firing traces from the fiber. B. Representative traces showed the firing of a single fiber at baseline, 0, 5, and 15 min after antidromic ES of dorsal roots. The animal received minocycline 24 h before CAP injection. Upper panel: the real- time histogram showing the spike frequency of the fiber with von Frey stimulation. Lower panel: original firing traces from the fiber. C. Statistical analysis showed that for firing of C fibers induced by 20 mN von Frey, no significant difference in antidromic ES-induced enhancement was detected among the 3 groups. D. Statistical analysis showed that firing of C fibers induced by 36 mN von Frey was dramatically increased; while at all the three time points, minocycline showed complete inhibition. *, p < 0.05; **, p < 0.01; Sal + Veh group compared with Veh.