RESUMEN
AIMS: Observing the parameter-specific anti-hyperalgesic effects of EA with different stimulation times and frequencies on painful hyperalgesia mediated by the level of TRPV1 and P2X3 expression in DRG after CFA injection. MAIN METHODS: The model was induced by the injection of CFA in each rat's right hind paw. EA treatment was applied to the bilateral ST36 and BL60. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were tested with Von Frey filaments and the radiant heat source of the test instrument, respectively. TRPV1 and P2X3 expressions were measured by immunofluorescence and western blot. αß-meATP and capsaicine combined with EA were further utilized to investigate the change in PWL. KEY FINDINGS: Different stimulation times (20, 30, 45â¯min) combined with different frequencies (2â¯Hz, 100â¯Hz, 2/100â¯Hz) of EA have analgesic effects on the PWT and PWL; however, the level of the hypoalgesic efficacy of EA was primarily associated with EA frequency. The analgesic effect of EA was better at 100â¯Hz than at 2â¯Hz. The level of regulation of 100â¯Hz EA on TRPV1 and P2X3 in DRG was greater than that of 2â¯Hz. Furthermore, both TRPV1 agonist and P2X3 agonist may impair the level of EA analgesia. SIGNIFICANCE: EA has a parameter-specific effect on chronic inflammatory pain relief, which primarily depend on the stimulation frequency and not on the stimulation time at a certain stimulation time. The parameter-specific analgesic effect of EA is at least partially related to mediation of the protein level of TRPV1 and P2X3 expression in DRG of CFA rats.