Cellular and molecular bases for rhythmic GnRH release

有节奏 GnRH 释放的细胞和分子基础

• 批准号: 10533876
• 负责人: Suzanne M MOENTER
• 金额: $ 56.89万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10533876
• 关键词: Action Potentials; Affect; Afferent Neurons; Animal Model; Calcium; Cardiovascular system; Castration; Cell membrane; Cells; Characteristics; Closure by clamp; Communication; Couples; Data; Development; Dynorphins; Electrophysiology (science); Elements; Endocannabinoids; Excision; Failure; Feedback; Female; Fertility; Fire - disasters; Frequencies; Generations; Glutamates; Goals; Gonadal Steroid Hormones; Gonadotropin Hormone Releasing Hormone; Grant; Health; Hormonal; Hormones; Hypothalamic structure; Image; Individual; Infertility; KISS1 gene; Knowledge; Lead; Link; Mathematics; Measures; Membrane Potentials; Metabolism; Methods; Modeling; Molecular; Monitor; Mus; Neuraxis; Neuroglia; Neurokinin B; Neurons; Neuropeptides; Neurosecretory Systems; Output; Pattern; Periodicity; Pharmacology; Physiologic pulse; Pituitary Gland; Poisoning; Population; Potassium; Preoptic Areas; Process; Production; Property; Prostaglandins; Proteins; Reporter; Reproduction; Reproductive Health; Reproductive system; Role; Sex Differences; Steroids; Structure of nucleus infundibularis hypothalami; Synapses; Synaptic Transmission; System; Testing; Time; Transgenic Mice; Vertebrates; Whole-Cell Recordings; Work; autocrine; base; bone; extracellular; gamma-Aminobutyric Acid; in silico; infertility treatment; interest; male; mathematical model; median eminence; paracrine; reproductive; response; sex; stem; substance use; therapy development; voltage

Reproductive health is a window to overall health. Fifteen to 20% of couples have difficulty conceiving; failures of the reproductive system thus affect a substantial population. Beyond fertility, sex steroids alter development and function of many systems, for example, bone, the central nervous system and the cardiovascular system. Episodic release of gonadotropin-releasing hormone (GnRH) is required for fertility in vertebrates of both sexes, and shifts in frequency of these pulses are essential for female reproductive cycles. The goal of this proposal is to increase our fundamental understanding of the generation of episodic release of GnRH as a critical link to understanding and modulating fertility. The proposed work will define intrinsic properties of GnRH neurons, local network interactions, and roles of glia and postulated driver neurons located in the arcuate nucleus of the hypothalamus that coexpress kisspeptin, neurokinin B and dynorphin (KNDy neurons). Our working hypothesis is that intrinsic and network mechanisms interact in local circuits to produce the final episodic output of the GnRH neurosecretory system. We will study this system using state-of-the-art electrophysiological, imaging and chemogenetic approaches combined with local measures of GnRH release in transgenic mice in which specific neurons are identified by expression of fluorescent reporter proteins. We will also extend our studies with mathematical modeling to generate hypotheses and return these hypotheses to the lab for testing. We have two specific aims. In Aim 1, we will examine how autocrine and paracrine factors from GnRH neurons and glia alter the relationship among action potentials, intracellular calcium and GnRH release, as well as how steroid feedback in males and females modifies these relationships. We will apply this knowledge to study how GnRH neurons are coordinated to produce pulses. We hypothesize factors from these circuit elements (GnRH neurons, afferent neurons, and glia) are needed for pulse generation. We will use pharmacologic and chemogenetic approaches to study the specific roles of these elements in organizing the GnRH network. In Aim 2, we will characterize intrinsic properties and synaptic input to GnRH neurons in intact vs. castrate mice of both sexes. We will use these data to move beyond independent characterization of isolated parameters and directly study how synaptic transmission interacts with intrinsic properties of GnRH neurons to alter action potential generation. Dynamic clamp is a method that allows these interactions to be studied. This is accomplished by careful modeling of these conductances, which can then be added to and/or subtracted from cells during recording. This occurs in real time through iterative interaction with the cell’s membrane potential, so that voltage-dependent changes in conductance are precisely controlled, and effects of the conductances on the membrane potential and firing of the cell are recorded. By examining pulse generation from these two angles, an integrated picture will emerge that adds to our understanding of this phenomenon. All necessary animal models and methods are in place to complete these studies.

生殖健康是整体健康的窗口。 15％至20％的夫妇很难受孕；失败 因此，生殖系统影响了大量人群。除生育能力外，性类固醇改变了发育 以及许多系统的功能，例如骨骼，中枢神经系统和心血管系统。 促性腺激素释放激素（GNRH）的情节释放是两种脊椎动物的生育需要的 性别和这些脉冲频率的变化对于女性复制循环至关重要。目标的目标 建议是增加我们对GNRH发行发行的一代的基本理解 与理解和调节生育能力的关键联系。拟议的工作将定义GNRH的内在特性 神经元，局部网络相互作用以及位于弧形中的神经胶质和假定的驱动神经元的作用 下丘脑的核，该下丘脑共表达亲吻肽，神经蛋白B和dynorphin（KNDY神经元）。我们的 工作假设是内在和网络机制在本地电路中相互作用，以产生最终 GNRH神经分泌系统的情节输出。我们将使用最先进的 电生理，成像和化学方法与GNRH释放的局部测量 在通过表达荧光报告蛋白表达的特定神经元的转基因小鼠中。我们 还将通过数学建模扩展我们的研究以产生假设并返回这些假设 到实验室进行测试。我们有两个具体的目标。在AIM 1中，我们将研究自身分泌和旁分泌 GNRH神经元和神经胶质的因素改变了作用电位之间的关系，细胞内钙和 GNRH释放，以及男性和女性的类固醇反馈如何改变这些关系。我们将 应用这些知识来研究GNRH神经元如何协调以产生脉冲。我们假设因素 从这些电路元件（GNRH神经元，传入神经元和神经胶质）中，脉冲产生需要。我们 将使用药物和化学发生方法来研究这些元素在 组织GNRH网络。在AIM 2中，我们将表征内在特性和突触输入到GnRH 完整的性别与castrate小鼠的神经元。我们将使用这些数据超越独立 孤立参数的表征，并直接研究合成传递如何与固有的相互作用 GnRH神经元的特性改变了动作电位产生。动态夹具是一种允许这些的方法 相互作用要研究。这是通过对这些电导的仔细建模来实现的，然后可以是 在记录过程中添加到和/或从单元中减去。这是通过迭代互动实时发生的 凭借电池的膜电位，使电压依赖性变化得到精确控制， 电导对膜电位和电池的发射的影响。通过检查 从这两个角度产生脉搏，将出现一整图片，这增加了我们对 这个现象。所有必要的动物模型和方法都可以完成这些研究。