蛛网膜下腔阻滞对大鼠丙泊酚镇静作用的影响

Effects of subarachnoid bupivacaine block on sedation of propofol in rats

目的观察布比卡因蛛网膜下腔阻滞对大鼠丙泊酚镇静作用的影响,并探讨其可能的机制。方法7只雌性SD大鼠,分别在蛛网膜下腔置管后,随机分为实验组(布比卡因组)和对照组(生理盐水组)行交叉试验。大鼠蛛网膜下腔注射0.75%布比卡因20μl或生理盐水20μl,10分钟后静脉泵注丙泊酚,比较两组大鼠眼睑反射消失时丙泊酚的用量及所需的时间。结果布比卡因组使大鼠眼睑反射消失的丙泊酚用量(7.6±0.6mg/kg)明显少于生理盐水组(10.8±0.8mg/kg)(P<0.01);大鼠眼睑反射消失所需时间布比卡因组(324±52s)也明显少于生理盐水组(499±59s)(P<0.01)。结论布比卡因蛛网膜下腔阻滞能减少大鼠丙泊酚的镇静用量并缩短眼睑反射消失的时间。

Objective To investigate the effects of subarachnoid bupivacaine block on sedation of propofol in rats and probe into its possible mechanism. Methods 7 female Sprague-Dawley （SD） rats were included in this study. After intrathecal catheter placement individually, rats were randomly divided into experimental group （Bupivacaine group） and control group （Normal saline group） in a crossover design study. Each rat received either 20 micro liter of 0.75% bupivacaine or 20 micro liter of normal saline intrathecally, intravenous infusion of propofol started at 10 minutes after intrathecal injection, the dosage and onset time of propofol required to ablate the eyelid reflex were compared between two groups. Results The dose of propofol required to ablate the eyelid reflex were significantly decreased with intrathecally administered normal saline versus intrathecally administered bupivacaine from 10.8±0.8 mg/kg to 7.6±0. 6 mg/kg （ P 〈0.01 ）, the onset time was from 499±59 second to 324 ±52 second （ P 〈 0.01 ）. Conclusion Subarachnoid bupivacaine block can reduce propofol requirement to ablate the eyelid reflex in rats. Most speculated mechanism for sedation during subarachnoid block is the indirect central effect of spinal deafferentation.