Atosiban及纳洛酮对缩宫素镇痛作用的影响

目的观察atosiban和纳洛酮对缩宫素（oxytocin，OT）中枢痛觉调制作用的影响。方法雄性sD大鼠随机分为鞘内注射组和侧脑室注射组2个大组。每个大组又分为7个剂量组：生理盐水＋OT组（C组）；atosiban＋OT高、中、低剂量组；纳洛酮＋OT高、中、低剂量组。各组大鼠在切割给药后的10min、30min、1h、3h、6h、12h、24h进行机械性痛阈测定，检测其变化情况。结果鞘内和侧脑室内预注射atosiban大鼠在注射OT后各时间点痛阈均低于c组（P〈0．05）；预注射纳洛酮大鼠注射中、低剂量OT后痛阈较C组大鼠降低（P〈0．05）；预注射纳洛酮大鼠注射0．25nmol OT后其痛阈与C组差异无统计学意义（P〉0．05）。结论鞘内和侧脑室内预注射atosiban可以阻断OT的镇痛作用，纳洛酮部分阻断OT镇痛效应。

Role of atosiban and naloxone in analgesic effects of oxytocin

Objective To study the role of atosiban and naloxone in the analgesic effects of oxytocin （OT）. Methods Male SD rats were divided randomly into 2 groups, i. th group and i. c. v group. And both groups subdivided as below ： N. S ＋ OT （ control group, C） ;atosiban ＋ OT low, medium and high dose groups;naloxone ＋ OT low, medium and high dose groups. And the mechanical pain threshold was tested 10 min,30 min,1 h,3 h,6 h, 12 h,24 h after incision in all of the rats. Results I. th and i. c. v administration of atosiban could thoroughly inhibit the analgesia effect of OT（ P 〈 0.05 ） ; compared with control group, the pain threshold of rats with naloxone only decreased after low and medium doses of OT（ P 〈 0.05 ） ; the pain threshold had no significant differences between the high dose OT treated rats and the control group（ P 〉 0.05 ）. Conclusions The analgesic effect of OT can be totally inhibited by i. t. h or i. e. v atosiban, but partly depressed by naloxone.