CANNABINOID-INDUCED DISRUPTION OF THE REPRODUCTIVE AXIS

描述：(申请人摘要) 大麻素的主要作用之一是抑制 重要生殖激素黄体生成素和催乳素 通过下丘脑的作用部位从脑下垂体部发出。总目标 这一建议的核心是理解细胞机制(S) 大麻素影响视前内侧区神经元的兴奋性 (POA)和下丘脑弓状核(ARC)降低 促黄体生成素和催乳素的分泌。将在豚鼠身上研究c-annabinid的作用。 因为在女性中生殖周期和性腺类固醇激素 与雌性灵长类动物的侧貌相似。为了进行比较，研究也将 在男性中进行，以检查潜在的性别差异。女性是 卵巢切除前一周，用苯甲酸雌二醇组治疗24小时 在此之前，控制性腺类固醇固有变异的实验 荷尔蒙。完整的雄性在24小时前被注射芝麻油车辆 控制注射效果的实验。具体来说，我会 G蛋白偶联脑型大麻素(CB1)分布的测定 POA和下丘脑内侧基底区受体在特异性靶点1的应用 放射配基和GTP伽马S放射自显影。在具体目标2中，我将评估 大麻素是否间接兴奋A12多巴胺神经元。这将是 使用锐化电极和全细胞膜片钳记录完成 下丘脑片中充满生物细胞的电极。我会确定是否 大麻素抑制已知可抑制A12多巴胺的GABA能ARC中间神经元 神经元通过调制K电流和/或突触输入；从而减弱 GABAA受体介导的突触传入后一组神经元和 最终影响到解除抑制。在具体目标3中，我将确定是否 大麻素抑制POA和ARC中的促性腺激素释放激素神经元 通过使用尖电极调制K电导和/或突触输入 生物细胞素填充电极的全细胞膜片钳记录 下丘脑片。这些研究将整合电生理学、 将药理和分子生物学技术融合为多学科 研究大麻素在下丘脑神经分泌细胞中作用的方法，以及 将有助于阐明大麻素诱导的细胞机制(S) 抑制至关重要的生殖荷尔蒙。

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.