CONTROL OF THE RESPIRATORY SYSTEM BY THE HYPOTHALAMUS

本提案中的研究目的是调查 下丘脑参与呼吸控制 系统 一些研究表明， 下丘脑参与调节一些心血管疾病， 反射 例如，心血管对 压力感受器和外周化学感受器的刺激 已知是由下丘脑中的位点修饰的。 即使 这些受体的激活也会影响通气，几乎没有 研究已经检查了下丘脑在调节 呼吸反应。 因此，研究的具体目的 本提案中描述的是调查以下方面的潜在作用： 调节呼吸反射的下丘脑部位， 确定下丘脑利用的神经递质 调节呼吸的部位。 呼吸反射 所研究的是由1）肺牵张刺激诱发的那些 受体（Hering-Breuer反射）; 2）外周化学感受器; 3） 中枢化学感受器和4）动脉压力感受器。 三套 将在麻醉的猫中进行实验。 一是 改变神经元的“兴奋状态”的影响， 下丘脑部位对呼吸反射的影响 测定 兴奋性状态将被化学物质或 电刺激，并将降低电解损伤 或通过下丘脑部位的局部冷却。 的第二集合中 实验对呼吸反射的影响， 将神经递质拮抗剂微量注射到 将评估下丘脑。 最后，将确定是否 上面列出的呼吸刺激改变放电频率 下丘脑神经元。 从这些获得的信息 实验应该增加对神经系统的全面理解， 控制呼吸。 这些发现可能会提供深入了解 神经系统异常导致一些中枢神经系统疾病 呼吸系统疾病

The purpose of the research in this proposal is to investigate hypothalamic involvement in the control of the respiratory system. Several studies have demonstrated that areas in the hypothalamus are involved in modulating some cardiovascular reflexes. For example, the cardiovascular responses to stimulation of baroreceptors and peripheral chemoreceptors are known to be modified by sites in the hypothalamus. Even though activation of these receptors also affects ventilation, almost no research has examined a role of the hypothalamus in regulating respiratory responses. Therefore, the specific aims of the studies described in this proposal are to investigate a potential role of hypothalamic sites in regulating respiratory reflexes and to determine the neurotransmitters utilized by the hypothalamic sites which modulate breathing. The respiratory reflexes to be studied are those evoked by stimulation of 1) pulmonary stretch receptors (Hering-Breuer reflex); 2) peripheral chemoreceptors; 3) central chemoreceptors and 4) arterial baroreceptors. Three sets of experiments will be performed in anesthetized cats. First, the effects of changing the "excitability state" of neurons in selected hypothalamic sites upon the respiratory reflexes will be determined. The excitability state will be raised by chemical or electrical stimulation and will be lowered by electrolytic lesions or by focal cooling of hypothalamic sites. In a second set of experiments the effects upon the respiratory reflexes of microinjecting neurotransmitter antogonists into the hypothalamus will be evaluated. Finally, it will be determined if the respiratory stimuli listed above alter the discharge frequency of hypothalamic neurons. The information gained from these experiments should add to the overall understanding of the neural control of respiration. These findings may offer insights into the neurological abnormalities responsible for some central respiratory disorders.