ROLE OF VENTROLATERAL MEDULLA IN THE BAROREFLEX

该应用程序建议调查去甲肾上腺素 猫的尾侧延髓腹外侧区(VLM)内含有神经元 动脉血压的急剧升高和肾上腺素的兴奋 吻侧VLm内含神经元可被下丘脑室旁核 动脉血压。此外，还提出了尾侧VLm神经元 单突触或单突触对吻侧VLM神经元活动的影响 连接或通过间接路径。因此，两国之间的互动 尾侧和吻侧VLm神经元构成VLm的神经元机制 猫是压力感受性反射控制交感神经活动的一部分。 VLM神经元是压力感受器反射的一部分的概念将是 麻醉猫在单次神经支配下的实验研究 分离颈动脉窦(其他压力感受器区域去神经)并制备 用于记录尾侧和吻侧VLm的单位活动 神经元。VLM神经元对压力感受器输入的行为将是 通过系统强迫颈动脉窦压力和记录进行检查 对这种压力感受器输入作出反应的神经元活动。完工后 在每个实验中，这些猫的脑干将被加工成 去甲肾上腺素和肾上腺素的免疫细胞化学鉴定 含有神经元的。含有去甲肾上腺素的神经元将被鉴定为 那些只用多巴胺-β-羟基酶抗体染色的神经元 (兔)和含有肾上腺素的神经元 苯乙醇胺-N-甲基转移酶抗体(兔)。他们的回应 单个神经元的特性将与它们的位置相关 在含去甲肾上腺素和肾上腺素的神经元群体中 超光速飞行器。建议进行更多的实验来研究可能的 尾侧VLM神经元影响活动的神经通路 吻侧室管膜神经元。首先，VLM尾侧神经元投射到 同侧吻侧VLm将通过使用逆行扫描来确定 微刺激和/或尖峰触发的记录场的平均 潜力。第二，尾端和吻端之间的单突触联系 将通过记录VLM神经元的同步活动来研究 对这些神经元进行互相关分析和应用。 第三，从尾侧VLm到VLm的间接通路的可能性 通过NTS中的神经元对吻侧VLM神经元进行研究 VLM尾侧核轴突投射的电生理测定 对同侧NTS的联合电生理 孤束核至同侧吻部轴突投射的测定 VLm.拟议的实验应该有助于理解 VLM在压力感受性反射控制循环中的作用。

The application proposes to investigate the hypothesis that noradrenaline containing neurons in the caudal ventrolateral medulla (VLM) of the cat are excited by acute increases in arterial blood pressure and that adrenaline containing neurons in the rostral VLM are inhibited by acute increases in arterial blood pressure. Further it is proposed that caudal VLM neurons influence the activity of rostral VLM neurons either through monosynaptic connections or through indirect pathways. Thus, interactions between caudal and rostral VLM neurons constitute neuronal mechanisms in the VLM of the cat that are part of baroreflex control of sympathetic nerve activity. The concept that VLM neurons are part of the baroreflex will be investigated in anesthetized cats prepared with a single innervated isolated carotid sinus (other baroreceptor regions denervated) and prepared for the recording of single unit activity of caudal and rostral VLM neurons. The behavior of VLM neurons to baroreceptor input will be examined by systematically forcing carotid sinus pressure and recording neuronal activity in response to this baroreceptor input. After completion of each experiment the brain stem of these cats will be processed for immunocytochemical identification of noradrenaline and adrenaline containing neurons. Noradrenaline containing neurons will be identified as those neurons that stain only with dopamine-beta-hydroxylase antibodies (rabbit) and adrenaline containing neurons as those that stain with phenylethanolamine-N-methyltransferase antibodies (rabbit). The response properties of individual neurons will be correlated to their location within populations of noradrenaline and adrenaline containing neurons in the VLM. Additional experiments are proposed to investigate the probable neural pathways through which caudal VLM neurons can influence the activity of rostral VLM neurons. First, the projection of caudal VLM neurons to the ipsilateral rostral VLM will be determined through the use of antidromic microstimulation and/or spike-triggered averaging of recorded field potentials. Second, monosynaptic connections between caudal and rostral VLM neurons will be investigated by recording simultaneous activity from pairs of these neurons and application of cross correlation analysis. Third, the possibility of an indirect pathway from the caudal VLM to rostral VLM neurons via neurons in the NTS will be investigated by electrophysiologic determination of axonal projections from the caudal VLM to the ipsilateral NTS in combination with the electrophysiologic determination of axonal projections from the NTS to the ipsilateral rostral VLM. The proposed experiments should contribute to the understanding of the role of VLM in baroreflex control of the circulation.