鞘内依咪酯对大鼠足底皮下注入蜜蜂毒诱致持续性痛的抑制作用

Suppressive effects of intrathecal etomidate on persistent pain induced by intraplantar bee venom injection in the conscious rat

目的：研究依咪酯在脊髓水平有无镇痛作用．方法：采用鞘内给药方法观察依咪酯对大鼠足底皮下注入蜜蜂毒诱致持续性痛反应的抑制效应．结果：①鞘内插管术未引起运动障碍及其它毒性反应，对大鼠皮下注入蜜蜂毒（ＢＶ）诱致的１ｈ内缩足反应总次数鞘内插管组［（６８６．１７±５５．０１）次／ｈ，ｎ＝７］与单纯ＢＶ注入组［（６０２．７１±４７．７３）次／ｈ，ｎ＝６］比较无统计学差别（Ｐ＞０．０５）；②鞘内注射３个剂量的依咪酯对ＢＶ诱致的缩足反应具有剂量依赖性抑制作用．与鞘内注射脂肪乳组总缩足次数［（６３３．００±６９．５０）次／ｈ，ｎ＝６］比较，剂量４０μｇ组对大鼠缩足反应的抑制率为１０．３３％［（５６７．６０±５１．４９）次／ｈ，ｎ＝５］；剂量８０μｇ组抑制率为２９．９４％［（４４３．５７±６２．８７）次／ｈ，ｎ＝７］；剂量１２０μｇ组抑制率为４２．６４％［（３８３．１０±１２．８３）次／ｈ，ｎ＝５］，其中剂量８０μｇ和１２０μｇ组与鞘内注射脂肪乳组比较均有显著差异．结论：本研究证实鞘内依咪酯可抑制大鼠足底皮下注入蜜蜂毒诱致的痛反应，依咪酯在脊髓水平存在镇痛作用．

IM: To study whether etomidate has analgesic actions at the spinal level. METHODS: By using intrathecal drug administration technique, the effects of etomidate on subcutaneous bee venominduced persistent pain behavior were studied. RESULTS: The animals receiving intrathecal (i.t.) tubing did not display any motor disturbance and other toxic reaction. It was also found that there was no significant difference in the total number of flinches within 1 h induced by bee venom injection between the i.t. tubing group and the bAuthor ee venom only group (602.7147.73) times/h, n=6] (P>0.05), suggesting that i.t. tubing did not cause any change in flinching reflex. Intrathecal pretreatment with three doses of etomidate produced a dosedependent suppression of the bee venominduced flinching reflex, the inhibitory rates being 10.33% 51.49) times/h, n=5] at 40 g, 29.94% =7] at 80 g and 42.64% at 120 g compared with that of the vehicle (lipid emulsion) group ]. At the dose of 80 g and 120 g, the total mean number of flinches during 1 h time course was significantly suppressed compared with that of the vehicle group. CONCLUSION: The present result showed that i.t. etomidate could suppress the bee venominduced persistant pain response in a dosedependent manner, suggesting that etomidate may exert its antinociceptive action partially at the spinal level.