昂丹司琼对异氟烷催眠和镇痛作用的影响

目的观察昂丹司琼对异氟烷催眠和镇痛作用的影响;探讨异氟烷的催眠、镇痛作用与5-羟色胺3受体(5-HT3)的关系。方法①催醒实验小鼠ip给予昂丹司琼1,2,4 mg·kg-1,15 min后ip给予异氟烷1.0 ml.kg-1催眠,检测翻正反射消失时间。②催眠半数有效量ED50测定小鼠ip给予昂丹司琼2 mg·kg-1,15 min后用序贯法ip给予异氟烷1.12,0.90,0.72,0.58和0.46 ml.kg-1,测定催眠ED50。③扭体法小鼠ip给予昂丹司琼1,2和4 mg·kg-1,10 min后sc给予异氟烷1.0 ml.kg-1镇痛,检测扭体次数。④热板法小鼠ip给予昂丹司琼1,2和4 mg·kg-1,10 min后,ip给予异氟烷0.4 ml.kg-1镇痛,检测小鼠热板法痛阈值(HPPT)。结果与正常对照组相比,昂丹司琼1,2和4 mg·kg-1组小鼠翻正反射消失持续的时间和ED50值均无明显变化。扭体实验中,与正常对照组比较,昂丹司琼4 mg·kg-1和异氟烷1.0 ml.kg-1可使清醒小鼠扭体次数减少(P<0.01),麻醉小鼠给予昂丹司琼1,2和4 mg·kg-1时,扭体次数有下降趋势,但无统计学差异。热板法中,ip昂丹司琼对清醒小鼠及异氟烷小鼠的HPPT均无明显影响。结论昂丹司琼对异氟烷催眠、抗热刺激伤害作用无明显影响,提示异氟烷的催眠镇痛作用可能与5-HT3受体无明显关系。

Effect of ondansetron on hypnotic and analgesic actions of isoflurane

OBJECTIVE To investigate the effect of ondansetron on hypnotic and analgesic effects of isoflurane and to explore their relationships with 5-HT3 receptors.METHODS ① Hypnosis experiment: Mice were ip given normal saline(NS) or ondansetron 1,2,4 mg·kg-1.15 min later,mice were also ip isoflurane 1.0 ml·kg-1 to get hypnotized and sleeping time was observed.② Hypnotic ED50 determination: Mice were ip given NS or ondansetron 2 mg·kg-1,15 min later,hypnotic ED50 of isoflurane was measured by sequential method.③ Writhing test: mice were divided into 8 groups,normal control,ondansetron 1,2,4 mg·kg-1,NS+isoflurane,ondansetron 1,2,4 mg·kg-1+isoflurane.Isoflurane 1.0 ml·kg-1 was sc given.The writhing times were observed.④ Hot-plate test: Mice were grouped as writhing test.Isoflurane 0.4 ml·kg-1 was ip given.The pain threshold in hot-plate pain test(HPPT) was observed.RESULTS Compared with normal control group,ondansetron had no significant effect on sleeping time in mice treated with isoflurane.There was no significant difference between ondansetron alone group and ondansetron+isoflurane group on ED50.Ondansetron 4 mg·kg-1 and isoflurane 1.0 ml·kg-1 could reduce writhing times(P<0.01).Compared with isoflurane group,the writhing times of ondansetron+isoflurane groups were slightly reduced,but were not significantly different.In hot-plate test,ondansetron did not affect the HPPT in conscious mice or those treated with isoflurane.CONCLUSION Ondansetron doesn′t affect the hypnotic or analgesic effects of isoflurane.Hypnotic and analgesic effects of isoflurane have no obvious relationship with 5-HT3 receptor.