MECHANISM OF CARDIORESPIRATORY RHYTHM IN NEONATES

心血管和呼吸系统的神经控制是 高度相互关联的。例如，在每个呼吸周期中，心脏 在灵感方面跳动得更快，在灵感后和 呼气(通常称为呼吸性窦性心律失常)。作为另一个人 例如，刺激感觉喉感受器会唤起一段时间的 呼吸暂停，并保持心率急剧下降。这喉头 反射在新生儿中可能被如此夸大，可能导致新生儿死亡 动物，并被认为可能是突然出生的婴儿的原因 死亡综合征(SIDS)。这种心肺相互作用发生在 并在很大程度上(如果不是完全的话)通过 心脏的迷走神经支配。然而，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，没有从已识别的呼吸道到 延髓内的心脏迷走神经细胞尚未被发现。 这个项目将直接检验喉上段的假设 运动神经元通过直接刺激迷走神经兴奋心脏抑制神经元 单突触通路，此外，在突触前作用于增强 其他突触撞击心脏迷走神经。喉上段 神经元可能是心肺相互作用的媒介，因为 这些神经元在吸气后活跃，与心脏共存。 迷走神经，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 心脏迷走神经和上心的AS荧光逆行识别 喉运动神经元与双膜片钳电生理 将使用各种技术。这项工作不仅将解决问题和 了解心肺疾病基础的基本机制 新生儿延髓的节律，但也会提示哪些受体和 心脏呼吸系统疾病的过程可能会改变。 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.