RETICULOSPINAL & VESTIBULOSPINAL CONTROL OF BACK MUSCLES

网状脊髓

• 批准号: 3376568
• 负责人: Donald W. Pfaff
• 金额: $ 10.63万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-02-01 至 1992-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3376568
• 关键词: electromyography; electrophysiology; electrostimulus; experimental brain lesion; hypothalamus; laboratory rat; microinjections; motor neurons; muscle contraction; neurobiology; neuroendocrine system; neuromuscular function; neuropeptides; reticulospinal tract; sex behavior; vestibular pathway

The descending systems comprised of medullary reticulospinal and lateral vestibulo-spinal neurons have been shown to be responsible for facilitating the execution of a mammalian behavior which has been proven to be unusually accessible to cellular and molecular analysis: the estrogen-progestin dependent reproductive behavior, lordosis. Contraction of the deep back muscles to an extent seen in no other behavior, upon somatosensory stimulation on specific regions of skin, is the neuromuscular basis of lordosis. The studies proposed here logically extend previous electrophysiological and behavioral work in our lab. I. Having already established reticulospinal and lateral vestibulospinal control over the deep back muscles lateral longissimus, medial longissimus and transverso-spinalis, we will determine the sensory ascending and brainstem descending neurons which project to the reticulospinal and vestibulospinal neuronal groups responsible. Using microstimulation with currents of 30mualpha or less, we will determine effective sites for the activation of deep back muscles, and use a low- diffusion method of application of retro-grade tracers developed in our lab to see which neurons are projecting to these sites. II. Since damage to the ventromedial nucleus of the hypothalamus can reduce lordosis behavior, we will use large ventromedial hypothalamic lesions (electrolytic or by excitotoxin microinjection) and electrical stimulation, as well as control lesions and stimulation, to discover some of the ways in which medial hypothalamic neurons can influence the ability of reticulospinal and vestibulospinal neurons to facilitate, in turn, deep back muscle motoneurons. Here, and throughout this project, we will use electromyographic (EMG) recording to advantage: it is a productive approach to measuring the output of the motoneuronal pools for deep back muscles. III. Since several hypothalamic neuropeptides have already been characterized with respect to their effects on lordosis behavior, it will be interesting to study their ability to influence the activation of deep back muscle motoneurons by reticulospinal or vestibulospinal neurons. For example, the decapeptide LHRH, known to facilitate reproductive behavior, can be contrasted to beta-endorphin, which decrease lordosis. Work with chronically prepared rats, throughout, will allow comparisons between electromyographic and behavioral observations, while larger numbers of parametric studies can be done efficiently in urethane- anesthetized animals. in the freely moving animals, comparisons of EMG activation across a variety of behavioral situations will reveal those patterns of activity which are specific to the extremely dorsiflexed posture of lordosis. Traditionally in neurobiology, it has been difficult to follow the mechanisms by which forebrain neurons could transmit signals through the brainstem reticular formation, to influence behaviors which are executed through motoneurons located in the spinal cord. These experiments extend our approach to discovering how hypothalamic neurons might influence one, concrete hormone-dependent reproductive behavior.

下降系统由髓质的网状脊髓和侧面组成 前庭脊柱神经元已被证明是造成的 促进已证明的哺乳动物行为的执行 要与细胞和分子分析不同。 雌激素 - 原生蛋白依赖性生殖行为，洛里虫。收缩 在没有其他行为的一定程度上，深背肌肉 皮肤特定区域的体感刺激是 神经病的神经肌肉基础。从逻辑上提出的研究 在我们的实验室中扩展以前的电生理和行为工作。 I.已经建立了网状脊髓和前庭脊髓脊髓 控制深背部肌肉横向longissimus，内侧 longissimus和ternverso-spinalis，我们将确定感觉 上升和脑干下降神经元，这些神经元投射到 负责的网状脊髓和前庭脊髓神经元组。使用 微刺激的电流为30mualpha或以下，我们将确定 有效的部位激活深背部肌肉，并使用低 - 在我们的 实验室以查看哪些神经元投影到这些站点。 ii。由于下丘脑的腹侧核的损害可以 减少脊柱障碍行为，我们将使用大型腹膜下丘脑 病变（电解或兴奋毒素显微注射）和电气 刺激以及控制病变和刺激，发现一些 内侧下丘脑神经元可以影响的方式 网状脊髓和前庭脊髓神经元的能力促进 转弯，深背肌肉运动神经元。在这里以及整个项目中，我们 将使用肌电图（EMG）记录来有利：这是一个 测量运动神经元池的输出的生产方法 深背肌肉。 iii。由于已经有几种下丘脑神经肽 以它们对脊柱降临行为的影响的特征，它将 研究他们影响深度激活的能力很有趣 网状或前庭脊髓神经元的背部肌肉运动神经元。为了 例如，已知可促进生殖行为的二肽LHRH， 可以与β-内啡肽形成鲜明对比，后者降低了脊柱障碍。 与长期准备的大鼠一起工作，将允许比较 在肌电图和行为观察之间，而较大 可以有效地进行尿电烷 - 可以有效地进行参数研究 麻醉动物。在自由移动的动物中，EMG的比较 在各种行为情况下的激活将揭示那些 特定于极具背屈的活动模式 脊柱的姿势。 传统上，在神经生物学方面，很难遵循 前脑神经元可以通过该机制传播信号 脑干网状形成，影响执行的行为 通过位于脊髓中的运动神经元。这些实验扩展了 我们发现下丘脑神经元如何影响一个的方法， 混凝土激素依赖性生殖行为。