右美托咪定对家兔压力反射敏感性的影响

Effects of dexmedetomidine on baroreflex sensitivity of rabbits

目的研究右美托咪定（dexmedetomidine，Dex）对家兔压力反射敏感性（baroreflex sensitivity，BRS）的影响，评估药物对迷走神经的张力影响。方法健康新西兰大白兔24只按随机数字表法分为3组（每组8只）：对照组（C组）、低剂量Dex组（D1组）和高剂量Dex组（D2组）。C组持续泵注生理盐水；D1组Dex负荷量10μg，kg，持续泵注量5μg·kg^-1·h^-1；D2组Dex负荷量60μg／kg，持续泵注量30μg·kg^-1·h^-1。于Dex给药前（Tn）、给药后30min（T1）和给药后60min（T2）用血管活性药物法测定BRS值。结果D1组和D2组BRS值在T1、T2时高于T0时（P〈0．05），D1组BRS值T2时较T1时明显降低（P〈0．05）。T1、T2时D1组和D2组BRS值较C组增高（P〈0．05），D2组BRS值较D1组增高（P〈0．05）.结论Dex增加家兔的BRS，BRS的增高随药物剂量的增加而更显著及持久．说明Dex剂量依籁性地增加诛走神绎张力．

Objective To investigate the effects of dexmedetomidine （Dex） on baroreflex sensitivit （BRS） of rabbits,and evaluate the effects of Dex on the tension of vagus nerve. Methods Twenty four healthy male rabbits were randomly divided into 3 groups（n=8）, including group C（control）, group Dl（low dose of Dex）, and group D2（high dose of Dex）. Rabbits were administered with Dex normal saline in group C, they were administered with Dex at loading dose of 10 μg/kg, and then pumped with Dex at 5 μg·kg^-1·h^-1 in group D1, they were administered with Dex at loading dose of 60 μg/kg and then at 30μg·kg^-1·h^-1 in group D2. The values of BRS was measured before（T0）, 30 min after（T1） and 60 rain after（T2） intravenous pumping of Dex. Results The values of BRS at T1, T2 in group D1 and D2 incareased compared with To （P〈0.05）, The values of BRS at T2 in group D1 decreased significantly compared with T1 （P〈0.05）. The values of BRS in group D1 and D2 were significantly increased than group C at T1, T2 （P〈0.05）. The values of BRS in group D2 were significantly increased than group D1 at T1, T2 （P〈0.05）. Conclusions Dex can increase BRS of rabbits, with increasing of Dex concentration of BRS increased effect are more significant and persistent, also which reflects the Dex can increase the vagus nerve tension in dose-dependent manner.