HYPOTHALAMIC CONTROL OF THE CARDIORESPIRATORY SYSTEMS

该实验室研究的长期目标是阐明其作用 下丘脑尾部神经元在调节心肺活动中的作用。 具体目的是：1)为生理学研究提供证据 下丘脑尾部神经元的功能；2)识别改变 已识别神经元的放电；3)确定尾侧的投射 下丘脑神经元至脑干和脊髓下部；以及4) 观察下丘脑尾部神经元对升高的可能贡献 自发性高血压大鼠体内存在压力。无论是在体内还是体内 体外制剂将用于解决这些目标。第一套 实验将在麻醉的猫身上进行。计算机信号 平均技术将被用来关联基础放电 下丘脑神经元频率与心动周期、交感神经的关系 活动和/或膈神经活动。此外，单个单位的响应 这些神经元对各种刺激(缺氧、高碳酸血症、压力感受器)的反应 激活，肺伸展感受器刺激)将被记录。一个 然后尝试确定所有神经元的轴突投射 使用逆行激活和映射技术进行了研究。一种体外试验 将利用大鼠脑片制备来评估直接效果 低氧和高碳酸血症对下丘脑尾部神经元的影响。整个细胞 脑片实验中将进行贴片记录； 罗丹明微珠的逆行运输将被用于尝试 确定所研究神经元的投射部位。活体实验将 在自发性高血压大鼠(SHR)中也进行了研究，以确定 下丘脑尾侧的神经元活动相对于 血压正常的大鼠。计算机平均技术将决定 下丘脑尾部有心脏和/或神经元的比例 交感神经放电。还将对每个神经元进行测试，以确定对 压力感受器刺激。在最后一组实验中，特征 自发性高血压大鼠下丘脑神经元的数量将与 血压正常的大鼠制作脑片。我们将进行比较 幼年和成熟自发性高血压大鼠的神经元和 血压正常的控制。这些研究的结果可能会提供一些见解 与神经异常有关的起源和/或 维持高血压和心肺反射改变。

The long-term goal of research in this laboratory is to elucidate the role of caudal hypothalamic neurons in regulating cardiorespiratory activity. The specific aims are to: 1) provide evidence for the physiological function of caudal hypothalamic neurons; 2) identify stimuli which alter the discharge of identified neurons; 3) determine projections of caudal hypothalamic neurons to lower brainstem and spinal cord sites; and 4) examine possible contributions of caudal hypothalamic neurons to elevated pressure present in spontaneously hypertensive rats. Both in vivo and in vitro preparations will be used to address these aims. The first set of experiments will be performed in anesthetized cats. Computer signal averaging techniques will be utilized to correlate basal discharge frequency of hypothalamic neurons with the cardiac cycle, sympathetic nerve activity and/or phrenic nerve activity. In addition, single unit responses of these neurons to various stimuli (hypoxia, hypercapnia, baroreceptor activation, pulmonary stretch receptor stimulation) will be recorded. An attempt will then be made to determine the axonal projection of all neurons studied using antidromic activation and mapping techniques. An in vitro rat brain slice preparation will be utilized to evaluate the direct effects of hypoxia and hypercapnia upon caudal hypothalamic neurons. Whole cell patch recordings will be performed in the brain slice experiments; retrograde transport of rhodamine microbeads will be used in an attempt to determine projection sites of studied neurons. In vivo experiments will also be undertaken in spontaneously hypertensive rats (SHR) to determine if neuronal activity in the caudal hypothalamus is altered relative to that of normotensive rats. Computer averaging techniques will determine the proportion of caudal hypothalamic neurons which have a cardiac and/or sympathetic discharge. Each neuron will also be tested for a response to baroreceptor stimulation. In a final set of experiments, characteristics of hypothalamic neurons from SHR rats will be compared to those of normotensive rats in a brain slice preparation. Comparisons will be made between neurons from young and mature spontaneously hypertensive rats and with normotensive controls. The results of these studies may offer insight into neurological abnormalities contributing to the origination and/or maintenance of high blood pressure and altered cardiorespiratory reflexes.