中文摘要：

为了探讨急性低血压通过外周前庭器官影响前庭神经核活动的部分神经化学机制,本实验利用脑部微量透析法和高效液相色谱法,观察静脉注射硝普钠（sodium nitroprusside,SNP）诱发急性低血压时,清醒大鼠前庭内侧核（medial vesti-bular nucleus,MVN）内γ-氨基丁酸（γ-aminobutyric acid,GABA）和甘氨酸（glycine,Gly）含量的变化。实验选用Wistar雄性清洁级大鼠72只,体重在（250±50）g,随机分为对照组、前庭器官损伤同侧组和前庭器官损伤对侧组。实验观察到,静脉注射SNP使血压平均下降30%时,MVN内GABA和Gly含量明显减少（P〈0.01）。用对氨基苯胂酸盐破坏单侧外周前庭器官两周后,静脉注射SNP使血压降低30%后,单侧前庭器官破坏同侧MVN内GABA和Gly含量无明显变化;而单侧前庭器官破坏对侧MVN内GABA和Gly含量明显减少（P〈0.01）。上述结果提示,清醒动物诱发急性低血压影响MVN功能活动过程中可能有GABA和Gly的参与。

英文摘要：

To understand whether some amino acids in the medial vestibular nucleus （MVN） of conscious rats are involved in the regulation of blood pressure,microdialysis technique and high performance liquid chromatography （HPLC） were used to measure the changes of γ-aminobutyric acid （GABA） and glycine （Gly） in this central area.Wistar rats （250-350 g） were randomly divided into three experimental groups：the control group with intact labyrinths;the ipsilateral MVN of unilateral labyrinthectomy （UL）;contralateral MVN of the UL.Acute hypotension was induced by intravenous infusion of sodium nitroprusside （SNP）.Unilateral chemical labyrinthectomy was performed 14 days before the start of the experiment to eliminate afferent signals from the peripheral vestibular receptors in the inner ear.Blood pressure decreased by 30% after SNP injection.In the control group,GABA and Gly release reduced to 43.53%±6.58% （P〈0.01） and 62.24%±7.51% （P〈0.01） respectively in the MVN following SNP-induced acute hypotension in conscious rats.In the contralateral MVN of UL,GABA and Gly release also reduced to 45.85%±17.27% （P〈0.01） and 73.30%±3.00% （P〈0.01） respectively following SNP-induced acute hypotension in conscious rats.In contrast,in the ipsilateral MVN of UL,GABA and Gly releases were not changed following SNP-induced acute hypotension in conscious rats.These results suggest that the SNP-induced acute hypotension may influence the activity of the neurons in the MVN by the afferent impulses from the peripheral vestibular organ,and that GABA and Gly may be involved in this process.