Abstract:

[Abstract]   Objective   To study the effects and current mechanism of low concentration of lidocaine on evokedbursting (EB) firing of dorsal root ganglion (DRG) neurons in rat model of chronic compression (CCD) of DRG．  Methods   Twenty-four SD rats were divided into normal control group (n=12) and CCD model group (n=12). CCD group was treated with chronic oppression on L4 and L5 DRG with L shape bar. Normal control group received no treatment. In vivo intracellular recording was used to record the incidence of EB and the effect of lidocaine on subthreshold membrane potential oscillation (SMPO). Patch clamp recording was used to record the effect of lidocaine on persistent sodium current (INaP).   Results   The incidence of EB increased in CCD group( 45.97%, 57/124), which was significantly different when compared with normal group (χ2=26.810, P < 0.01). The magnitude of SMPO, INaP and EB were inhibited in a reversible way by lidocaine (50μmol/L).   Conclusion   The low concentration of lidocaine might play an analgesic effect in peripheral nervous system by selectively inhibiting INap, which participates in SMPO formation.

Key words: neurons, Lidocaine, Dorsal root ganglion neuron, Evoked-bursting, sodium current