切口痛大鼠脊髓背角GluR1-AMPA受体和GluR2-AMPA受体胞浆至胞膜转运的变化

Changes in trafficking of GluRl-containing AMPA receptor and GluR2-containing AMPA receptor from cytoplasm to cell membrane in spinal dorsal horn in a rat model of incisional pain

目的探讨切口痛大鼠脊髓背角含谷氨酸受体1亚基的使君子酸（GluR1-AMPA）受体和含谷氨酸受体2亚基的使君子酸（GluR2-AMPA）受体胞浆至胞膜转运的变化。方法成年雄性清洁级sD大鼠32只，体重280～300g，6～8周龄，采用随机数表法，将其随机分为2组：正常对照组（C组，n=8）和切口痛组（I组，n=24）。I组大鼠制作右足底切口痛模型。I组于术后3h、1d和3d时取8只大鼠，测定累计痛评分（CPS）和机械缩足阈值（PWT）。然后处死大鼠，取L3-6节段脊髓背角，采用Western blot法检测胞浆和胞膜GluR1和GhtR2亚基的表达，采用免疫共沉淀技术检测脊髓背角Stargazin与GluR1或GluR2亚基的共表达。结果与C组比较，I组CPS评分升高，冈汀降低，脊髓背角胞浆GluR1亚基表达下调，脊髓背角胞膜GluR1表达及Stargazin与GluR1共表达上调（P〈0．05或0．01），脊髓背角胞浆和胞膜GluR2及Stargazin与GluR2共表达差异无统计学意义（p〉0．05）。结论切口痛大鼠脊髓背角GluR1-AMPA受体从胞浆转运至胞膜，而GluR2一AMPA受体不发生胞浆至胞膜的转运。

Objective To investigate the changes in traMcking of GluRl-containing AMPA （GluR1-AM- PA） receptor and GluR2-AMPA receptor from cytoplasm to cell membrane in the spinal cord dorsal ham in a rat model of incisional pain.Methods Thirty-two adult male SD rats aged 6-8 weeks weighing 280-300 g were randomly divided into 2 groups： control group （group C, n = 8） and incisional pain group （group I, n = 24）. An 1 cm long incision was made in the plantar surface of right hindpaw according to Brennan et al. in group I. Cumula- tive pain score （CPS） and paw-withdrawal threshold to von Frey stimuli （PWT） were measured at 3 h and day 1 and 3 after incision （TL2,3）. The animals were sacrificed after pain behavior assessment. Their lumbar segments of the spinal cord （ L3~ ） were removed. The expression of GluR1 and GluR2 in cell membrane and Cytoplasm in spinal cord dorsal ham was determined by Western blot analysis. The co-expression of Stargazing with GluR1 and GluR2 in the spinal cord dorsal horn was examined by co-immuno-precipitation. Results The CPS was increased and PWT decreased; the GluR1 expression in cytoplasm was decreased while the expression of GluR1 in cell membrane and the co-expression of Stargazing with GluR1 were up-regulated in group I as compared with group C. There was no significant change in the expression of GluR2 in cytoplasm and cell membrane and the co-expression of Stargazing with GluR2 in group I as compared with group C. Conclusion GluR1-AMPA receptor transfers from cytoplasm to cell membrane but GluP,2-AMPA receptor does not in rats with incisional pain.