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CANNABINOID-INDUCED DISRUPTION OF THE REPRODUCTIVE AXIS

大麻素引起的生殖轴破坏

基本信息

批准号：
6378338
负责人：
EDWARD J WAGNER
金额：
$ 10.55万
依托单位：
WESTERN UNIVERSITY OF HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-09-30 至 2003-08-31
项目状态：
已结题

项目摘要

DESCRIPTION: (Applicant's Abstract) One of the principal actions of cannabinoids is to inhibit the secretion of the important reproductive hormones luteinizing hormone (LH) and prolactin (PRL) from the anterior pituitary via a hypothalamic site of action. The overall goal of this proposal is to understand the cellular mechanism(s) by which cannabinoids affect the excitability of neurons in the medial preoptic area (POA) and the arcuate nucleus (ARC) of the hypothalamus to decrease the secretion of LH and PRL. C annabinoid effects will be studied in the guinea pig because in the female the reproductive cycle and gonadal steroid hormone profile parallel those of the female primate. For comparison, studies also will be conducted in males to examine potential sex differences. Females are ovariectomized one week prior to, and treated with estradiol benzoate 24 hr prior to, experimentation to control for inherent variations in gonadal steroid hormones. Intact males are injected with sesame oil vehicle 24 hr before experimentation to control for injection effects. Specifically, I will determine the distribution of the G-protein coupled brain cannabinoid (CB1) receptor in the POA and the mediobasal hypothalamus in Specific Aim 1 using radioligand and GTP gamma S autoradiography. In Specific Aim 2, I will evaluate whether cannabinoids indirectly excite A12 dopamine neurons. This will be accomplished using sharp electrode and whole-cell patch clamp recordings with biocytin-filled electrodes in hypothalamic slices. I will ascertain whether cannabinoids inhibit GABAergic ARC interneurons known to inhibit A12 dopamine neurons by modulating K+ currents and/or synaptic input; thereby attenuating GABAA receptor-mediated synaptic input onto this latter group of neurons and ultimately affecting a disinhibition. In Specific Aim 3, I will determine if cannabinoids inhibit gonadotropin-releasing hormone neurons in the POA and ARC by modulating K+ conductances and/or synaptic input using sharp electrode and whole-cell patch clamp recordings with biocytin-filled electrodes in hypothalamic slices. These studies will integrate electrophysiological, pharmacological and molecular biological techniques into a multidisciplinary approach to study cannabinoid actions in hypothalamic neurosecretory cells, and will help to elucidate the cellular mechanism(s) underlying cannabinoid-induced suppression of critically important reproductive hormones.

描述：（申请人摘要）大麻素的主要作用之一是抑制重要的生殖激素促黄体生成素（LH）和催乳素（PRL）从垂体前叶通过下丘脑作用部位。总目标这一建议的目的是了解细胞机制，大麻素影响内侧视前区神经元的兴奋性 (POA)和下丘脑弓状核（ARC），以减少 LH和PRL的分泌。将在豚鼠中研究C类胭脂树红的作用因为雌性的生殖周期和性腺类固醇激素与雌性灵长类动物的轮廓相似为了比较，研究还将在男性中进行，以检查潜在的性别差异。女性卵巢切除前一周，用苯甲酸雌二醇处理24小时在控制性腺类固醇的固有变化的实验之前，荷尔蒙在24小时前，向完整雄性动物注射芝麻油溶剂实验以控制注射效果。具体来说，我会确定G蛋白偶联的脑大麻素（CB 1）的分布受体在POA和下丘脑中的特异性Aim 1使用放射性配体和GTP γ S放射自显影。在具体目标2中，我将评估大麻素是否间接刺激A12多巴胺神经元。这将是使用尖电极和全细胞膜片钳记录完成，下丘脑切片中的生物胞素填充电极。我会查明大麻素抑制已知抑制A12多巴胺的GABA能ARC中间神经元神经元通过调节K+电流和/或突触输入;从而衰减 GABAA受体介导的突触输入到后一组神经元上，最终影响抑制解除。在具体目标3中，我将确定大麻素抑制POA和ARC中的促性腺激素释放激素神经元通过使用尖锐电极调制K+电导和/或突触输入，全细胞膜片钳记录与生物胞素填充电极，下丘脑切片这些研究将整合电生理学，药理学和分子生物学技术，研究大麻素在下丘脑神经分泌细胞中作用的方法，将有助于阐明大麻素诱导的细胞机制抑制至关重要的生殖激素。