Bautista Tara G, Dutschmann Mathias
Florey Institute of Neuroscience and Mental Health, Gate 11, Royal Parade, University of Melbourne, Victoria, 3052, Australia.
Florey Institute of Neuroscience and Mental Health, Gate 11, Royal Parade, University of Melbourne, Victoria, 3052, Australia
J Physiol. 2014 Jun 15;592(12):2605-23. doi: 10.1113/jphysiol.2014.272468. Epub 2014 Mar 17.
Both swallowing and respiration involve postinspiratory laryngeal adduction. Swallowing-related postinspiratory neurons are likely to be located in the nucleus of the solitary tract (NTS) and those involved in respiration are found in the Kölliker-Fuse nucleus (KF). The function of KF and NTS in the generation of swallowing and its coordination with respiration was investigated in perfused brainstem preparations of juvenile rats (n = 41). Orally injected water evoked sequential pharyngeal swallowing (s-PSW) seen as phasic, spindle-shaped bursting of vagal nerve activity (VNA) against tonic postinspiratory discharge. KF inhibition by microinjecting isoguvacine (GABAA receptor agonist) selectively attenuated tonic postinspiratory VNA (n = 10, P < 0.001) but had no effect on frequency or timing of s-PSW. KF disinhibition after bicuculline (GABAA receptor antagonist) microinjections caused an increase of the tonic VNA (n = 8, P < 0.01) resulting in obscured and delayed phasic s-PSW. Occurrence of spontaneous PSW significantly increased after KF inhibition (P < 0.0001) but not after KF disinhibition (P = 0.14). NTS isoguvacine microinjections attenuated the occurrence of all PSW (n = 5, P < 0.01). NTS bicuculline microinjections (n = 6) resulted in spontaneous activation of a disordered PSW pattern and long-lasting suppression of respiratory activity. Pharmacological manipulation of either KF or NTS also triggered profound changes in respiratory postinspiratory VNA. Our results indicate that the s-PSW comprises two functionally distinct components. While the primary s-PSW is generated within the NTS, a KF-mediated laryngeal adductor reflex safeguards the lower airways from aspiration. Synaptic interaction between KF and NTS is required for s-PSW coordination with respiration as well as for proper gating and timing of s-PSW.
吞咽和呼吸都涉及吸气后喉部内收。与吞咽相关的吸气后神经元可能位于孤束核（NTS），而参与呼吸的神经元则位于柯利克 - 富斯核（KF）。在幼年大鼠（n = 41）的灌流脑干标本中研究了KF和NTS在吞咽产生及其与呼吸协调中的作用。经口注入水诱发顺序性咽部吞咽（s - PSW），表现为迷走神经活动（VNA）相对于持续性吸气后放电的阶段性、纺锤形爆发。通过微量注射异谷酰胺（一种GABAA受体激动剂）抑制KF可选择性减弱持续性吸气后VNA（n = 10，P < 0.001），但对s - PSW的频率或时间没有影响。在微量注射荷包牡丹碱（一种GABAA受体拮抗剂）后解除对KF的抑制会导致持续性VNA增加（n = 8，P < 0.01），从而使阶段性s - PSW模糊并延迟。在抑制KF后，自发性PSW发生率显著增加（P < 0.0001），但在解除对KF的抑制后未增加（P = 0.14）。微量注射异谷酰胺到NTS可减弱所有PSW的发生（n = 5，P < 0.01）。微量注射荷包牡丹碱到NTS（n = 6）导致无序PSW模式的自发激活以及呼吸活动的长期抑制。对KF或NTS进行药理操作也会引发呼吸吸气后VNA的深刻变化。我们的结果表明，s - PSW由两个功能不同的成分组成。虽然主要的s - PSW在NTS内产生，但由KF介导的喉部内收肌反射可保护下呼吸道免受误吸。KF和NTS之间的突触相互作用对于s - PSW与呼吸的协调以及s - PSW的正确门控和定时是必需的。
