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10 min、30 min、1 h、3 h、6 h、12 h、24 h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0.25 nmol 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。

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.c.v atosiban, but partly depressed by naloxone.