Figure 3

CFA injection increases excitability of TMJ neurons. (A) An example of a Dil-labeled TG neuron (arrow). A star showing the place where a neuron is not labeled by DiI. (B) A phase image of the same TG neuron labeled by DiI is shown on the bottom (arrow) and the neuron not labeled by DiI is shown on the top (*). Bar = 50 μm. Patch clamp recordings were performed on DiI labeled TG neurons. A total of 22 DiI-labeled neurons from control rats and 26 DiI-labeled neurons from CFA-treated rats were recorded under current clamp conditions. (C) CFA injection significantly depolarized resting membrane potentials (RP) of TG neurons innervating TMJ (**p < 0.01, compared with NS, Mann-Whitney test). (D) CFA injection markedly reduced rheobase (*p < 0.05, compared with NS, Mann-Whitney test). (E) Example of action potential (AP) trances evoked by 2X (left) and 3X (right) rheobase current stimulation of TMJ innervating TG neurons from NS- (top) and CFA- (bottom) injected rats. (F) Bar graphs showed that CFA injection greatly increased numbers of AP evoked by 2X (left) and 3X (right) rheobase current stimulation (*p < 0.05, **p < 0.01, compared with NS, Mann-Whitney test).