胶质细胞代谢对新生大鼠离体延髓脑片呼吸节律性放电的影响

Effect of glial cell metabolism on respiratory rhythmical discharge activity in neonatal rat medulla oblongata slices

目的探讨胶质细胞代谢在延髓基本节律性呼吸放电的作用。方法制备12只新生SD大鼠(0～3d)离体延髓脑片标本,以改良的Kreb's液(MKS)恒温灌流,稳定记录到与之相连的舌下神经的呼吸节律性放电活动(RRDA)后,第一组在灌流液中分别单独给予胶质细胞代谢激动剂L-谷氨酰胺(L-GLN)和拮抗剂L-硫酸蛋氨酸(L-MSO),第二组先后给予L-MSO和L-MSO+L-GLN,观察舌下神经根RRDA变化。结果给予L-MSO后,呼吸周期(RC)和呼气时程(TE)显著延长,吸气时程(TI)和放电积分幅度(IA)降低;给予L-GLN后RC、TE明显缩短,TI、IA无明显变化,且L-MSO的呼吸抑制作用可被L-GLN逆转。结论胶质细胞代谢在哺乳动物基本节律性呼吸的调节中起着重要的作用。

Objective To explore the role of glial cell metabolism in the generation and regulation of central respiratory rhythm. Methods The medulla oblongata slices （600-700 μm） containing the medial region of the nucleus retrofacialis （mNRF） with the hypoglossal nerve rootlets retained from 12 neonatal （0-3 days） Sprague-Dawley rats were prepared and perfused with modified Kreb＇s solution （MKS）. Upon recording of respiratory rhythmical discharge activity （RRDA） of the rootlets of the hypoglossal nerve, the brain slices were treated with glial cell metabolism antagonist L-methionine sulfoximine （L-MSO, 50 μmol/L） for 20 min followed by application of glial cell metabolism agonist L-glutamine （L-GLN, 30 μmol/L） for 20 min, or with L-MSO for 20 min with additional L-GLN for 20 min. The changes in the RRDA of the rootlets of the hypoglossal nerve in response to the treatments were recorded. Results L-MSO prolonged the respiratory cycle （RC） and expiratory time （TE）, and reduced the integral amplitude （ IA） and the inspiratory time （TI） in the brain slices. L-GLN induced a significant decrease in RC and TE, but IA and TI showed no obvious variations. The effect of L-MSO on the respiratory rhythm was reversed by the application of L-GLN. Conclusion Glial cell metabolism may play an important role in the modulation of RRDA in neonatal rat brainstem.