ELECTROPHYSIOLOGICAL CORRELATES OF VASOPRESSIN RELEASE

描述：加压素（VP）和催产素（OT）是必不可少的， 维持正常的水平衡，血压，盐排泄， 生殖过程 了解基本功能 神经元合成这些激素对于理解分泌 调控 视上OT和VP神经元在许多方面是相似的， 某些形态学和电生理学特征不同， 受到动物分泌状态的动态影响。 等 差异可能是刺激-分泌偶联的差异的基础， OT和VP。 该项目的具体目标是确定：1）时间 收缩过程、可逆性和收缩依赖性（OT神经元）， 树突状细胞（VP神经元）扩张，并观察到电生理变化 持续哺乳期; 2）是否树突状Ca++瞬变引起的 OT神经元的反向传播峰电位增强，VP神经元的反向传播峰电位减弱 在哺乳期; 3）是否OT和VP轴突的分支模式， 不同，以及是否树枝状变化与哺乳;和4）是否OT 和VP轴突不同的频率依赖性的尖峰传播，尖峰 增宽和轴突Ca++瞬变，差异是否相关 与形态，以及这些属性是否由泌乳调制。 研究了树枝状结构的时间过程， 妊娠、哺乳和断奶期间的电生理特性将 确定这些特性是否与改变的神经元 神经元的活动，或者这些变化是否是由卵巢引起的。 妊娠期激素分泌模式。 Ca++依赖 过程是重要的体树突功能，包括局部激素 钙离子依赖性电流的释放和控制 模式. 反向传播尖峰增加枝晶的效率 [Ca++]i将针对两种细胞类型进行检查，同样将检查这种细胞类型的调节。 通过局部释放激素反馈而增加。 对哺乳期大鼠的调查将确定 峰电位活性、树突状细胞（Ca++]i和局部激素释放之间的关系是 国家依赖。 同样，轴突几何形状将被量化和比较 对顶芽茎穗繁殖能力的影响 切片 Ca++成像将用于确定是否频率依赖性 OT和VP对[Ca++]i和激素释放的促进作用不同 终端，无论它们是否与尖峰展宽，尖峰 传播和轴突形态，以及它们是否随 哺乳期

DESCRIPTION: Vasopressin (VP) and oxytocin (OT) are essential for maintaining normal water balance, blood pressure, salt excretion and reproductive processes. An understanding of the basic function of the neurons synthesizing these hormones is paramount to understanding secretory regulation. Supraoptic OT and VP neurons are similar in many regards, yet certain morphological and electrophysiological characteristics differ and are dynamically influenced by the secretory state of the animal. Such differences may underlie differences in stimulus-secretion coupling between OT and VP. The specific aims of the project are to determine: 1) the time course, reversibility and hormone-dependence of shrinkage (OT neurons), dendritic expansion (VP neurons), and electrophysiological changes observed duration lactation; 2) whether dendritic Ca++ transients resulting from back-propagating spikes are enhanced in OT, and diminished in VP neurons during lactation; 3) whether the arborization patterns of OT and VP axons differ, and whether arborization changes with lactation; and 4) whether OT and VP axons differ in the frequency-dependence of spike propagation, spike broadening, and axonal Ca++ transients, whether differences are correlated with morphology, and whether these properties are modulated by lactation. Investigations of the time course of dendritic architectural and electrophysiological properties during gestation, lactation and weaning will determine whether these properties are correlated with the altered neuronal activity of the neurons, or whether these changes are induced by the ovarian hormone secretion pattern characterizing gestation. Ca++-dependent processes are important to somatodendritic function, including local hormone release and the control of Ca++-dependent currents regulating firing patterns. The efficiency of back-propagating spikes to increase dendritic [Ca++]i will be examined for both cell types, as will the modulation of this increase by feedback from locally released hormone. Investigation of lactating rats will determine whether the relationship between spike activity, dendritic (Ca++]i, and local hormone release is state-dependent. Similarly, axonal geometry will be quantified and compared to the spike-propagating ability of the terminal arbor in neural lobe slices. Ca++ imaging will be used to determine whether frequency-dependent facilitation of [Ca++]i and hormone release differ between OT and VP terminals, whether they relate to differences in spike-broadening, spike propagation, and axonal morphology, and whether they vary as a function of lactation.