The effect of cannabinoid receptor 2 agonist JWH015 on the hyperalgesia induced by remifentanil / 中华行为医学与脑科学杂志

ABSTRACT

ObjectiveTo investigate the effects of cannabinoid receptor 2 (cannabinoid receptor 2,CB2R) agonist JWHO15 on the hyperalgesia induced by remifentanil in a rat model of postoperative pain.Methods Sixty SD rats were randomly divided into 10 groups ( n =6 each )control groups ( C1 and C2 ),incisional pain groups (I1 and I2),incisional pain plus JWHO15 groups (QI and FI),remifentanil groups (R1 and R2),and JWHO15 plus remifentanil groups ( QR and FR).Rats in group QL/QR and FI/FR were intrathecal injection with 10μg JWHO15 ( diluted in 10μl 20％ DMSO solution) and intraperitoneal administration with 100μg JWHO15 ( diluted in 10μl 4％ DMSO solution) respectively 30 min before plantar incision while rats in group C,I and R were received with the same volume of DMSO solution.Plantar incision surgery was operated in rats of group I,R,QI/FI,and QR/FR.In group R and QR/FR,remifentanil (0.04 mg/kg) was infused subcutaneously to rats with a pump for 30 min at the moment of surgical incision.The paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) at 24 h before incision and at 2 h,6 h,24 h and 48 h after incision were tested to evaluate the behavioral changes.ResultsCompared with group C and baseline,the level of PWMT and PWTL decreased at 2 h,6 h,24 h and 48h after incision in group Ⅰ (P＜ 0.01 ) ;Compared with group Ⅰ,the significant decrease of PWMT and PWTL were observed after incision in group R (P ＜ 0.05 ) ; Compared with group R,the significant increase of PWMT (7.78 ± 1.09) and PWTL ( 17.28 ± 1.58) were observed from 6 h after incision in group QR(P＜0.05).And the increase of PWMT (7.79 ±0.72,9.50 ± 1.17,7.86 ± 1.16) and PWTL ( 16.23 ± 1.50,19.53 ± 1.63,18.10 ± 0.93) were observed at 6 h,24 h and 48 h after incision in group FR(P＜0.05).ConclusionIntrathecal and intraperitoneal administration of JWHO15 in this investigation dose could relief remifentanil-induced hyperalgesia in a rat model of postoperative pain.