Role of TRPV1 in ectopic spontaneous activity of chronic compressed DRG neurons
AIM: To study the effect of the Capsazepin(CZP), a blocker of the transient receptor potential subfamily vanilloid member 1 (TRPV1), on the spontaneous firing with different pattern originating from the injured dorsal root ganglion(DRG). METHODS: Under anesthesia and sterilized surgery, a piece of stainless steel filament(4 mm in length and 0.5-0.8 mm in diameter) was inserted into L5 intervertobral foramen in rats, thus producing a steady and chronic compression on the DRG and its nerve root. The behaviors of models were observed and ectopic spontaneous discharges originating from neurons of the compressed DRGs were recorded through single dorsal root fiber. The characteristics and the frequency of firing from both the CZP-treated A type afferents and that of control were analyzed. RESULTS: Twenty-four hours after the compression, significant pain behaviors were observed in the models. The weight distribution period was obviously prolonged to (10.5± 2.1 ) s/min (P＜0.05 ). Most compressed DRG neurons (32/35) displayed large ectopic spontaneous activities, including 14 with periodic pattern and 18 with nonperiodic pattern. After the bath of CZP(3 μmol/L) in the compressed DRG, the frequency of most(14/22) eetopic sponta-neous discharges dropped obviously from ( 27.7±2.2 ) Hz to (15.5±2.0) Hz(n =4, P ＜0.05) for regular activities, and from (34.7±7.4) Hz to (17.2±5.2) Hz (n=10, P＜0.05) for nonperiodie activities. CONCLUSION: After blocking TRPV1, the ectopic spontaneous activities of the compressed DRG neurons are restrained, indicating that TRPV1 may involve in the process of inducing and maintaining the ectopic spontaneous activities from compressed DRG neurons and may mediate the transmission of the neuropathie pain from DRGs to CNS.
NETL
NSTL
万方数据
维普
