利多卡因中耳内灌注对前庭神经核氨基酸类递质的影响

Amino acid transmitters releasing in medial vestibular nucleus following lidocaine infusion in middle ear

[目的]观察利多卡因中耳内灌注后前庭神经内侧核(MVN)区部分氨基酸类神经递质含量的变化.[方法]在麻醉状态下将20 g/L利多卡因1.2 mL在10 min内分5次行大鼠中耳内灌注,采用脑部微量透析法和高效液相色谱法测定同侧MVN区部分氨基酸类递质含量.[结果]利多卡因中耳内灌注后同侧MVN区天冬氨酸、谷氨酸及谷氨酰胺含量明显减少,甘氨酸和丙氨酸含量明显增多,牛磺酸呈双相(先升后降).[结论]中耳内灌注利多卡因阻断单侧前庭传入,可引起同侧MVN内兴奋性氨基酸含量降低,而抑制性氨基酸含量升高,提示利多卡因的抗眩晕及耳鸣的作用机制可能与抑制外周前庭器官的功能进而改变其向中枢的冲动传递有关.

OBJECTIVE To invesgate the change of some amino acids in the medial vestibular nucleus （MVN） of rats infused lidocaine into the unilateral middle ear of rats. METHODS The microdialysis technique and high performance liquid chromatography （HPLC） were used to measure the changes of some special amino acid in the MVN, after infusing 20 g/L lidocaine 1.2 mL into the unilateral middle ear of rats by 5 times in 10 minutes. RESULTS The release of aspartate, glutamate, glntamine was significantly reduced,and of glycine and alanine was increased in the MVN of rats after infusing lidocaine into middle ear. CONCLUSION Lidocaine can influence the activity of the neurons of the MVN by the afferent impulses from vestibular organ, and some special amino acid transmitters in the MVN could be participate in the process.