MECHANISM OF CARDIORESPIRATORY RHYTHM IN NEONATES

心血管和呼吸系统的神经控制是 高度相关。例如，在每个呼吸周期中， 在吸气时心跳更快，在吸气后心跳减慢， 呼气（通常称为呼吸性窦性心律失常）。作为另一 例如，刺激感觉喉感受器会引起一段时间的 呼吸暂停并保持心率急剧下降。这喉 新生儿的反射如此夸张，可能导致新生儿死亡。 动物，并已被认为是一个可能的原因，突然婴儿 死亡综合征（SIDS）。这种心肺相互作用发生在 中枢神经系统，如果不是全部，也主要是通过 心脏的迷走神经支配令人惊讶的是，尽管 心脏迷走神经活动的生理和临床重要性， 已知其在中枢神经系统内的启动和控制 在新生儿或成人中，未发现从已确定的呼吸道至 在髓质内的心脏迷走神经元尚未被鉴定。 本项目将直接检验上级喉 运动神经元通过直接的 单突触通路，此外，突触前作用，以增强 其他突触撞击心脏迷走神经元。上级喉 神经元可能是心肺相互作用的介质， 这些神经元在吸气后活跃，与心脏共同定位， 迷走神经元，并在疑核内有许多轴突侧支。 为了验证这一假设，该领域相当新的技术，如 作为心脏迷走神经和上级的荧光逆行识别 喉运动神经元和双膜片钳电生理 技术将被使用。这项工作不仅将解决问题， 了解心肺基础的基本机制 节奏在新生儿髓质，但也将建议哪些受体和 在心肺系统疾病中， 例如小岛屿发展中国家。

The neural control of the cardiovascular and respiratory systems are highly interrelated. For example, in each respiratory cycle the heart beats more rapidly in inspiration and slows during post-inspiration and expiration (often referred to as respiratory sinus arrhythmia). As another example, stimulation of sensory laryngeal receptors evokes a period of apnea and maintained a dramatic decrease in heart rate. This laryngeal reflex can be so exaggerated in newborns in can lead to death in neonatal animals, and has been suggested as a possible cause for sudden infant death syndrome (SIDS). This cardio-respiratory interactions occur within the central nervous system and are mediated largely, if not entirely, via the vagal innervation of the heart. Surprisingly, however, despite the physiological and clinical importance of cardiac vagal activity, little is known about its initiation and control within the central nervous system in neonates or adults, and no pathway from identified respiratory to cardiac vagal neurons within the medulla has yet been identified. This project will directly test the hypothesis that superior laryngeal motor-neurons excite vagal cardioinhibitory neurons via a direct monosynaptic pathway, and, in addition, act presynaptically to enhance other synapses impinging on cardiac vagal neurons. Superior laryngeal neurons are likely mediators of cardio-respiratory interaction because these neurons are active in post-inspiration, co-localized with cardiac vagal neurons, and have many axon collaterals within the nucleus ambiguus. To test this hypothesis, techniques that are quite new to this field, such as fluorescent retrograde identification of cardiac vagal and superior laryngeal motor-neurons, and dual patch clamp electrophysiological techniques will be used. This work will not only address issues and mechanisms fundamental to understanding the basis of cardio-respiratory rhythms in the neonatal medulla, but will also suggest which receptors and processes could be altered in diseases of the cardio-respiratory system such as SIDS.