Guyenet Patrice G, Bayliss Douglas A, Stornetta Ruth L, Fortuna Michal G, Abbott Stephen B G, DePuy Seth D
Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA.
Respir Physiol Neurobiol. 2009 Aug 31;168(1-2):59-68. doi: 10.1016/j.resp.2009.02.001. Epub 2009 Feb 13.
Breathing automaticity and CO(2) regulation are inseparable neural processes. The retrotrapezoid nucleus (RTN), a group of glutamatergic neurons that express the transcription factor Phox2b, may be a crucial nodal point through which breathing automaticity is regulated to maintain CO(2) constant. This review updates the analysis presented in prior publications. Additional evidence that RTN neurons have central respiratory chemoreceptor properties is presented, but this is only one of many factors that determine their activity. The RTN is also regulated by powerful inputs from the carotid bodies and, at least in the adult, by many other synaptic inputs. We also analyze how RTN neurons may control the activity of the downstream central respiratory pattern generator. Specifically, we review the evidence which suggests that RTN neurons (a) innervate the entire ventral respiratory column and (b) control both inspiration and expiration. Finally, we argue that the RTN neurons are the adult form of the parafacial respiratory group in neonate rats.
呼吸自动调节和二氧化碳调节是不可分割的神经过程。延髓头端腹外侧区（RTN）是一组表达转录因子Phox2b的谷氨酸能神经元，可能是调节呼吸自动调节以维持二氧化碳恒定的关键节点。本综述更新了先前出版物中的分析。文中给出了更多关于RTN神经元具有中枢呼吸化学感受器特性的证据，但这只是决定其活动的众多因素之一。RTN还受到来自颈动脉体的强大输入调节，至少在成年动物中，还受到许多其他突触输入的调节。我们还分析了RTN神经元如何控制下游中枢呼吸模式发生器的活动。具体而言，我们综述了相关证据，这些证据表明RTN神经元（a）支配整个腹侧呼吸柱，（b）控制吸气和呼气。最后，我们认为RTN神经元是新生大鼠面旁呼吸组的成年形式。
