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Objective:To investigate the different suppressive effect of lidocaine on persistent Na

+

current and transient Na

+

current in injured or uninjured dorsal root ganglion neurons.Methods:Totally 23 SD rats were randomly divided into 2 groups:control group（n=10） and chronically compressed DRG（dorsal root ganglion） group （CCD group

n=13）.Rats were anesthetized and DRG was isolated.Single DRG neuron was isolated by enzymatic disassociation method.Persistent Na

+

current(I

NaP

) and transient Na

+

current(I

NaT

) were elicited in voltage clamp mode.Results:The presence of I

NaP

was testified in most DRG neurons （38/46 neurons in CCD group and 31/39 neurons in control group

P

>

0.05）.However

the cur- rent density of I

NaP

in CCD group（4.6±0.6 pA/pF

n=38 neurons） was greater than that in control group （2.5±0.4 pA/pF

n=31 neurons）（P

<

0.05）.The characteristics of I

NaP

was observed and found that I

NaP

could be blocked by 0.2μmol/L tetrodotoxin easily.Furthermore

the does-effect relationship of lidocaine on I

NaP

and I

NaT

were also examined.I

NaP

and I

NaT

were suppressed by different concentrations of li- docaine

the range for I

NaP

was 5-20μmol/L and for I

NaT

was 0.05-2 mmol/L.Conclusion:I

NaP

and I

NaT

were suppressed by different concentrations of iidocaine.I

NaP

was suppressed by very low concentration of lidocaine（5-20μmol/L）.However

I

NaT

could only be blocked by high concentration of lidocaine（0.05-2 mmol/L）.