脊髓背角神经元ATP敏感性钾通道在大鼠开胸术后痛觉过敏中的作用

Role of ATP-sensitive potassium channel in spinal dorsal horn neurons in hyperalgesia after thoracotomy in rats

目的评价脊髓背角神经元ATP敏感性钾通道（KATP通道）在大鼠开胸术后痛觉过敏中的作用。方法雄性SD大鼠，体重250～350g，7～9周龄，开胸术后慢性痛模型制备成功后第14天行鞘内置管，置管后5d选择鞘内置管成功的大鼠28只，采用随机数字表法，将大鼠随机分为4组（n=7）：空白对照组（C组）、溶媒组（DMSO组）、KATP通道开放剂毗那地尔组（P组）、KATP通道阻断剂格列本脲组（G组）。DMSO组、P组和G组分别鞘内注射10％DMSO10脚，吡那地尔10μg／10μl，格列本脲50μg／10μl。于鞘内给药前，给药后10、30、60min时测定大鼠机械痛阈，并行冷丙酮实验，测定冷刺激痛阈。结果4组各时点机械痛阈比较差异无统计学意义（P〉0．05）。与C组和DMSO组比较，P组冷刺激痛阈升高，G组冷刺激痛阂降低（P〈0．05）。C组和DMSO组冷刺激痛阂比较差异尢统计学意义（P〉0．05）．、结论脊髓背角神经元KATP通道参与了大鼠开胸术后痛觉过敏的维持。

Objective To evaluate the role of ATP-sensitive potassium （KAyP ） channel in spinal dorsal horn neurons in hyperalgesia after thoracotomy in rats. Methods Twenty-eight Sprague-Dawley rats, aged 7-9 weeks, weighing 250-350 g, in which intrathecal catheters were successfully implanted without complications on 14th day afler chronic post-thoracotomy pain was induced, were randomly divided into 4 groups （ n = 7 each） ： control group, the solvent dimethyl sulfoxide （DMSO） group, KATp channel opener pinacidil group （group P） and KATp channel blocker glibenclamide group （group G）. 10% DMSO 10 μl, pinacidil 10 μg/10 μl and glibenclamide 50 μg/10 μl were injected intrathecally in groups DMSO, P and G at 5 day after the intrathecal catheter was im- planted, respectively. Paw withdrawal threshold to yon Frey filament stimulation was measured before intrathecal administration and at 10, 30 and 60 rain after intrathecal administration and the acetone test was performed. Cold- induced pain threshold was measured. Results There was no significant difference in paw withdrawal threshold to yon Frey filament stimulation at each time point among the four groups （ P 〉 0.05）. Compared with C and DMSO groups, cold-induced pain threshold was significantly increased in group P and decreased in group G （P 〈 0.05）. There was no significant difference in cold-induced pain threshold between C and DMSO groups （ P 〉 0.05） . Con- clusion KATP channel in spinal dorsal horn neurons is involved in the maintenance of hyperalgesia after thoracotomy in rats.