ELECTROPHYSIOLOGICAL CORRELATES OF VASOPRESSIN RELEASE

描述：加压素(VP)和催产素(OT)是 维持正常的水分平衡、血压、盐分排泄和 生殖过程。对国际货币基金组织基本职能的理解 神经元合成这些激素对于理解分泌至关重要。 监管。视上OT和VP神经元在许多方面是相似的，但 某些形态和电生理特征不同于 会受到动物分泌状态的动态影响。是这样的 差异可能是刺激-分泌偶联的不同基础 不是也不是副总裁。该项目的具体目标是确定：1)时间 收缩的可逆性和激素依赖性(OT神经元)， 树突状扩张(VP神经元)及电生理改变 持续哺乳期；2)树突状钙离子瞬变是否由 背向传播的棘波在OT中增强，而在VP神经元中减弱 3)OT轴突和VP轴突的树枝状分布模式 不同，以及分枝是否随哺乳而变化；以及4)OT 与VP轴突不同的是，脉冲传播的频率依赖性、脉冲 增宽和轴突钙离子瞬变，差异是否相关 与形态有关，以及这些特性是否受哺乳调节。 树枝状建筑的时间进程研究 妊娠、哺乳期和断奶期间的电生理特性 确定这些特性是否与改变的神经元相关 神经元的活动，或者这些变化是否由卵巢引起的 具有妊娠特征的激素分泌模式。依赖于钙离子 过程对躯体树突状细胞的功能很重要，包括局部激素 钙依赖电流调节放电的释放与控制 模式。反向传播穗对增加树枝状组织的效率 将检查这两种细胞类型的[Ca++]i，以及这两种细胞类型的调制 通过本地释放的荷尔蒙的反馈来增加。 对哺乳期大鼠的调查将确定是否与 在棘波活动、树突状细胞(Ca++]i和局部激素释放之间 依赖国家。类似地，轴突几何形状将被量化和比较。 对神经叶末梢茎刺激性的影响 切片。将使用CA++成像来确定频率依赖 OT和VP的[Ca++]i易化和激素释放不同 末端，无论它们是否与穗扩宽的差异有关，穗 传播和轴突形态，以及它们是否作为 哺乳。

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.