Department of Anesthesiology, University Medical Center, Georg-August University, 37099 Göttingen, Germany.
Int J Mol Sci. 2024 Mar 8;25(6):3128. doi: 10.3390/ijms25063128.
The preBötzinger complex (preBötC) and the Bötzinger complex (BötC) are interconnected neural circuits that are involved in the regulation of breathing in mammals. Fast inhibitory neurotransmission is known to play an important role in the interaction of these two regions. Moreover, the corelease of glycine and GABA has been described in the respiratory network, but the contribution of the individual neurotransmitter in different pathways remains elusive. In sagittal brainstem slices of neonatal mice, we employed a laser point illumination system to activate glycinergic neurons expressing channelrhodopsin-2 (ChR2). This approach allowed us to discern the contribution of glycine and GABA to postsynaptic currents of individual whole-cell clamped neurons in the preBötC and BötC through the application of glycine and GABA receptor-specific antagonists. In more than 90% of the recordings, both transmitters contributed to the evoked IPSCs, with the glycinergic component being larger than the GABAergic component. The GABAergic component appeared to be most prominent when stimulation and recording were both performed within the preBötC. Taken together, our data suggest that GABA-glycine cotransmission is the default mode in the respiratory network of neonatal mice with regional differences that may be important in tuning the network activity.
preBötzinger 复合体（preBötC）和 Bötzinger 复合体（BötC）是相互关联的神经回路，参与哺乳动物的呼吸调节。已知快速抑制性神经传递在这两个区域的相互作用中起着重要作用。此外，在呼吸网络中已经描述了甘氨酸和 GABA 的共释放，但单个神经递质在不同途径中的贡献仍不清楚。在新生小鼠的矢状脑切片中，我们使用激光点照明系统来激活表达通道视紫红质-2（ChR2）的兴奋性神经元。通过应用甘氨酸和 GABA 受体特异性拮抗剂，这种方法使我们能够区分甘氨酸和 GABA 对 preBötC 和 BötC 中单个全细胞钳制神经元的突触后电流的贡献。在超过 90%的记录中，两种递质都对诱发的 IPSC 有贡献，其中甘氨酸能成分大于 GABA 能成分。当刺激和记录都在 preBötC 内进行时，GABA 能成分似乎最为突出。总之，我们的数据表明，GABA-甘氨酸共传递是新生小鼠呼吸网络的默认模式，具有区域差异，这可能对网络活动的调节很重要。
