摘要目的观察非N-甲基-D-门冬氨酸(NMDA)受体对延髓脑片吸气神经元和双相呼气神经元活动的调节作用,以进一步探讨非NMDA受体参与基本呼吸节律产生的可能机制.方法在新生大鼠延髓脑片上同步记录舌下神经根和双相呼气神经元/吸气神经元单位的放电活动,并在灌流的改良Kreb's液中先后加以非NMDA受体的激动剂KA和拮抗剂DNQX,观察对神经元单位放电的影响.结果使用非NMDA受体激动剂KA以后,双相呼气神经元的放电频率和峰频率都明显增大,吸气神经元中期放电的频率和峰频率也显著增大,而早期和晚期放电的频率无明显改变;用相应拮抗剂以后,上述效应明显被抑制.结论非NMDA受体参与了双相呼气神经元之间的交互兴奋作用,同时也介导了吸气神经元的兴奋性突触输入.

abstractsObjective To study the role of non-NMDA receptors in modulating activities of inspiratory neurons and biphasic expiratory neurons in the brain stem slice. Methods Simultaneous recordings of the XII nerve activity and the inspiratory/biphasic expiratory (biphasic E) neuronal discharge were conducted in neonatal rat brainstem slice. After stabilization for over 10 minutes, the slices were then superfused with kainic acid (KA, 8.0 μmol/L) and trans-l-aminocyclopentane-1,3-dicarboxylic acid (DNQX, 3.0 μmol/L) by tums. The effects of these agents on the activity of inspiratory and biphasic expiratory neurons were investigated. Results A total of 11 inspiratory and 7 biphasic E neurons were identified.After bath application of the non-NMDA receptor agonist kainic acid (KA), the peak firing frequencies of both types of neurons were increased. For inspiratory neurons, the increases occurred after the inspiration on-switch and concluded before the inspiration off-switch. For biphaic E neurons, however, the increases were more evident and covered the whole firing phase. The KA effects could be reversed by administration of the non-NMDA receptor antagonist trans-1 -aminocyclopentane-1, 3-dicarboxylic acid (DNQX). Conclusion Non-NMDA receptors are mainly involved in the maintenance of the respiratory rhythm, rather than the rhythm generation in neonatal rats.