Objective:To investigate the involvement of the distal cerebrospinal fluid contacting neurons (CSF-CNs)in modulation of neuropathic pain induced by chronic contriction injury. Methods:The CB-HRP/pERK1/2 double-labeling method was used to observe the expression of pERK1/2 in CB-HRP positive neurons following the chronic contriction injury. Results:After four loose ligatures were placed on left sciatic nerve at 1mm intervals according to the method described by Bennett,thermal paw withdrawal latencies decreased remarkably,and companied by the increased expression of pERK1/2 in the CB-HRP labeled neurons. Conclusion:The distal CSF-CNs may be involved in the processing of neuropathic pain induced by chronic contriction injury.