Effect Of Vestibular Afference On Amino Acids Levels In The Medial Vestibular Nucleus Of Rats

Objective:To investigate the effects of vestibular afferent impulse on amino acids levels in medial vestibular nucleus of anesthetized rats.Methods:The levels of amino acids such as aspartate(Asp),glutamate(Glu),glutamine (Gln),Glycine(Gly),taurine(Tau),and alanine(Ala)in medial vestibular nucleus(MVN)were measured by brain microdialysis and high liquid chromatogram analysis after the MVN were infusing with 40℃water or 2% lidocaine to middle ear.Results:1.40℃water decreased levels of Asp,Tau,Gly,and Gln in the MVN(P＜0.05 vs control respectively).The levels of Glu in the MVN were unchanged by 40℃water.2.2%of lidocaine decreased levels of Asp,Glu,Gln(P＜0.05,P＜0.05,and P＜0.01 vs control respectively)but increased levels of Gly and Ala(P＜0.05 vs control respectively).The effects of Asp and Glu levels were continued about 80 min and the Gln levels were continued about 100 min.2%lidocaine-increased effects of gly and Ala were continued about 30 min and then returned to the baseline by 60 min recovery processes.The levels of Tau were increased by 2% lidocaine in initially(continued about 10 min,P＜0.01 vs control)and then showed fluctuated changes that decreased and peaked at 50 min and returned to the baseline through 60 min recovery processes.Conclusion:Some amino acids such as Asp,Tau,Glu,Gln and Gly may be involved in the action of excitatoty MVN activeity in anesthetized rats.