Relationship between remifentanil-induced hyperalgesia and TMEM16C and Slack channel in spinal dorsal horn of rats with incisional pain / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the relationship between remifentanil-induced hyperalgesia and Antamins family member membrane protein 16C ( TMEM16C) and Slack channel in the spinal dorsal horn of rats with incisional pain. Methods Forty-eight male Sprague-Dawley rats, aged 1 month, were studied. The study was performed in two parts. Experiment Ⅰ Twenty-four rats were divided into 4 groups ( n=6 each) using a random number table method: normal saline group ( S group ) , virus vector group ( V group) , virus vector plus remifentanil plus incisional pain group ( VRI group) , and AAV5-TMEM16C o-ver-expression plus remifentanil plus incisional pain group (ORI group). Normal saline (S group), virus vector (V group and VRI group) or AAV5-TMEM16C (ORI group) 1 μl was injected via the L4,5 spinal dorsal horn. Remifentanil 1 μg ·kg-1 ·min-1 was infused for 60 min via the caudal vein at 30 days, and the incisional pain model was simultaneously established in VRI and ORI groups. The thermal paw withdrawal latency ( TWL) and mechanical paw withdrawal threshold ( MWT) were measured at 24 h before remifen-tanil infusion ( T0 ) and 2, 6, 24, and 48 h after stopping infusion ( T1-4 ) . The L4,5 segments of spinal dorsal horns were obtained at the end of the behavioral testing, and the expression of TMEM16C and Slack in total and membrane proteins was determined by Western blot. ExperimentⅡ Twenty-four rats were di-vided into 4 groups ( n=6 each) using a random number table method: normal saline plus artificial cerebro-spinal fluid (ACSF) group (SA group), virus vector plus ACSF group (VA group), virus vector plus remifentanil group ( VR group ) , and AAV5-TMEM16C over-expression plus remifentanil group ( OR group). Normal saline (SA group), virus vector (VA group and VR group) or AAV5-TMEM16C (OR group) 1μl were injected via the spinal dorsal horn at the level of L4,5 . L4,5 spinal cord slices were obtained at 30 days and incubated for 60 min in ACSF ( SA and VA groups ) or in ACSF containing 4 nmol∕L remifentanil ( VR group and OR group) . The whole-cell patch-clamp was used to measure the frequency and amplitude of the Slack channel current after the end of incubation in each group. Results ExperimentⅠCompared with S group, the TWL was significantly shortened and the MWT was decreased at T1-4 , and the expression of TMEM16C and Slack in total and membrane proteins was down-regulated in VRI group ( P<0. 05) . Compared with VRI group, the TWL was significantly prolonged and the MWT was increased at T1-4 , and the expression of TMEM16C and Slack in total and membrane proteins was up-regulated in ORI group ( P<0. 05) . Experiment Ⅱ Compared with SA group, the amplitude and frequency of Slack chan-nel current in spinal dorsal horns were significantly decreased in VR group ( P<0. 05) . Compared with VR group, the amplitude and frequency of the Slack current were significantly increased in OR group ( P<0. 05) . Conclusion The mechanism of remifentanil-induced hyperalgesia is related to down-regulating the expression of TMEM16C and further down-regulating the expression of the Slack channel in the spinal dorsal horn of rats with incisional pain.