G蛋白信号转导偏向性μ-阿片受体激动剂SWG-LX-33的镇痛药效和不良反应OA

OBJECTIVE To explore the analgesic efficacy and adverse reactions of SWG-LX-33,a G protein signal transduction biased-μ-opioid receptor agonist.METHODS ① HEK293 cells stably transfected with μ-opioid receptors were divided into the SWG-LX-33 0.1,1,10,100,1 000,10 000 nmol·L-1 and morphine 0.1,1,10,100,1 000,10 000 nmol·L-1 treatment groups.The content of cyclic adenosine monophosphate(cAMP)was detected by a kit.HEK-293 cells transiently transfected with μ-opioid receptor-Small BiT(MOR-SmBiT)and Large BiT-β-arrestin2(LgBiT-β-arrestin2)were divided into the vehicle,SWG-LX-33 1,10,100,1 000,10 000 nmol·L-1,[D-Ala2,N-Me Phe4,Gly-ol]-enkephalin(DAM-GO)10,100,1 000,10 000,100 000 nmol·L-1,and morphine 0.1,1,10,100,1 000 nmol·L-1 treatment groups.The Nano-Glo live cell reagent kit was used to detect the effect on the recruitment of β-arres-tin2 in HEK-293 cells.② Male ICR mice were divided into control(saline),SWG-LX-33,and morphine groups.The acute analgesic effects of SWG-LX-33 were evaluated using the thermal radiation induced tail-flick test and mechanical nociception test based on an incision pain model.In the tail-flick test,SWG-LX-33(13.9,19.6,28,40,56 mg·kg-1,ip)and morphine(3,4.5,6.7,10 mg·kg-1,sc)were admin-istered.In the incision pain model,SWG-LX-33(13.9,19.6,28,40,56 mg·kg-1,ip)and morphine(3,4.5,6.7,10,15 mg·kg-1,sc)were used,respectively.③ Male ICR mice were divided into the control,SWGLX-33(27,39 mg·kg-1,ip)or morphine(7 mg·kg-1,sc)treatment groups.Small animal blood oxygen meters were used to monitor the blood oxygen values after the administration of the compound 120 min.The partial pressure of oxygen in the aorta 50 minutes after drug administration was detected by a blood gas analyzer.④ Male ICR mice were divided into the SWG-LX-33(40 mg·kg-1,ip,twice a day)or morphine(10 mg·kg-1,sc,twice a day)treatment groups.They were administered for 6 consecutive days to observe analgesic tolerance.Naloxone was used to induce withdrawal to evaluate somatic dependence by observing the number of jumps in mice.RESULTS ① SWG-LX-33(0.1-10 000 nmol·L-1)could significantly reduce cAMP accumulation rather than induce the recruitment of β-arrestin2.② In the tail flick test,SWG-LX-33(56 mg·kg-1)and morphine(10 mg·kg-1)produced the maximum analgesic effects 30 min after administration.The median effective dose(ED50)of SWG-LX-33 and morphine was 21.73 and 4.57 mg·kg-1,respectively.In the incision pain model,SWG-LX-33(56 mg·kg-1)and morphine(15 mg·kg-1)produced the maximum analgesic effects 30 min after administration.The ED50 of SWG-LX33 and morphine was 29.17 and 6.35 mg·kg-1,respectively.③ Compared with control group,SWG-LX-33(39 mg·kg-1)and morphine(7 mg·kg-1)both significantly reduced the blood oxygen saturation of rats while SWG-LX-33(56 mg·kg-1)and morphine 10 mg·kg-1 significantly lowered the partial pressure of oxygen in abdominal aorta.④ Analgesic tolerance by using SWG-LX-33(40 mg·kg-1)or morphine(10 mg·kg-1)was developed after continuous administration in mice,but there was no signifi-cant difference in analgesic tolerance between the two groups.The number of jumps in mice with chronic treatment of SWGLX-33 was significantly smaller than in those with morphine treatment in the withdrawal test.CONCLUSION The adverse reactions of SWG-LX-33 regarding analgesic tolerance and respiratory depression are comparable to those of morphine,but its physical dependence is remarkably lower.