Li Xiang-Lan, An Ying, Jin Qing-Hua, Jin Yuan-Zhe
Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Key Laboratory of Natural Resources Changbai Mountain and Functional Molecules (Yanbian University), the State Educational Ministry of China, Yanji 133000, China.
Sheng Li Xue Bao. 2010 Feb 25;62(1):30-4.
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 gamma-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.
为了解清醒大鼠内侧前庭核（MVN）中的某些氨基酸是否参与血压调节，采用微透析技术和高效液相色谱法（HPLC）测量该中枢区域γ-氨基丁酸（GABA）和甘氨酸（Gly）的变化。将体重250 - 350 g的Wistar大鼠随机分为三个实验组：迷宫完整的对照组；单侧迷路切除术（UL）的同侧MVN组；UL的对侧MVN组。通过静脉输注硝普钠（SNP）诱导急性低血压。在实验开始前14天进行单侧化学迷路切除术，以消除内耳外周前庭感受器的传入信号。注射SNP后血压下降30%。在对照组中，清醒大鼠经SNP诱导急性低血压后，MVN中GABA和Gly的释放分别降至43.53%±6.58%（P<0.01）和62.24%±7.51%（P<0.01）。在UL对侧的MVN中也观察到，清醒大鼠经SNP诱导急性低血压后，GABA和Gly的释放分别降至45.85%±17.27%（P<0.01）和73.30%±3.00%（P<0.01）。相比之下，在UL同侧的MVN中，清醒大鼠经SNP诱导急性低血压后，GABA和Gly的释放未发生变化。这些结果表明，SNP诱导的急性低血压可能通过外周前庭器官的传入冲动影响MVN中神经元的活性，且GABA和Gly可能参与了这一过程。
