星形胶质细胞在七氟醚抑制节律性呼吸中的关键作用

摘要

目的 探讨星形胶质细胞在七氟醚对呼吸中枢抑制过程中是否发挥关键作用.方法 制作新生SD大鼠延髓脑片(包含延髓面神经后核内侧区),完整保留舌下神经根,用吸附电极记录舌下神经根的呼吸节律性放电.实验分为6组(n=8):对照组、七氟醚组、二氢卡因酸盐(DHK)组、L-蛋氨酸亚砜亚胺(MS)组、MS+DHK组、七氟醚+DHK组,分别通过生物机能学记录系统记录舌下神经根呼吸节律放电(RRDA),分析呼吸周期(RC)、吸气时程(IT)、吸气放电积分幅度(IA).结果 七氟醚对舌下神经根RRDA有抑制作用,RC延长了53.7％,IT缩短了15.5％,IA降低了19.4％.谷氨酸转运体拮抗剂DHK能够明显兴奋呼吸输出形式,表现为RC缩短26.7％,IA增高6.9％,IT变化不明显.胶质细胞代谢抑制剂MS对RRDA表现为抑制,RC延长31.8％,IT缩短26.4％,IA降低15.5％;在联合应用MS+DHK后对RRDA的影响不明显,七氟醚对RRDA的抑制作用能够被DHK所逆转.结论 在离体延髓脑片上星形胶质细胞能够参与基本节律性呼吸的发生,在七氟醚对呼吸中枢的抑制作用中发挥重要作用.%Objective The effect of astrocytes in the sevoflurane (SEV) mediated regulation of respiratory rhythm from the brainstem slice was identified.Methods Neonatal (aged 0～3 d)Sprague-Dawley rats of either sex were used.The brainstem slice containing the medial region of the nucleus retrofacialis and the hypoglossal nerve rootlets was prepared and the surgical procedure was performed in the artificial cerebrospinal fluid (ACSF) with continuous carbogen (95％O2 and 5％ CO2),and ended in 3 min.Respiratory rhythmical discharge activity (RRDA) of the hypoglossal nerve rootlets was recorded by suction electrode.The experiment was divided into 6 groups and treated for 10 min with ACSF,SEV(5％),dihydrokinate (DHK,300 μmol/L),L-methionine sulfoximine (MS,50 μmol/L),MS (50 μmol/L) + DHK (300 μmol/L),SEV (5％) +DHK (300 μmol/L).Results SEV had the inhibitory effect,and it could prolong the respiratory cycle,shorten respiratory time and decrease the integral amplitude.DHK,a selective blocker of GLT-1 (EAAT2) induced significant decrease in respiratory cycle,and increased integral amplitude.MS,a blockage of glutamine synthetase,was applied,and the RRDA was inhibited.The effect of SEV on the RRDA was reversed after co-perfusion of SEV and DHK.Conclusion Astrocytes was likely involved in the modulation of the normal RRDA and played the key role in SEV-mediated regulation of RRDA in the brainstem slice of neonatal rats.