Ovarian Hormone Regulation of LHRH Biosynthesis

描述（由申请人提供）：本研究的长期目标是确定卵巢类固醇如何触发促黄体生成素释放激素（LHRH）和LH峰释放，从而诱导排卵。在这些研究中，我们将探讨机制，通过光周期和雌激素信号相互作用，以调节新的双表型GABA/谷氨酸神经元的前腹侧室周核（AVPV）的女性。本研究的具体目的是：1）为了证实GABA/谷氨酸神经元与LHR神经元之间的直接联系，我们将在大鼠和小鼠中使用顺行和逆行追踪以及免疫细胞化学方法：2）我们将使用电生理学研究，其中通过GGP表达来鉴定LHRH神经元，以证实AVPV GABA/谷氨酸神经元在上午主要释放GABA，在下午主要释放谷氨酸; 3）确定加压素（VP）和/或去甲肾上腺素（NA）是否触发与LH峰相关的GABA释放的午间升高。我们将研究特定VP和NA受体拮抗剂对GABA释放标志物谷氨酸脱羧酶67（GAD 67）mRNA表达的影响。我们还将确定当动物置于恒定光照下时，GAD 67 mRNA水平的变化是否被阻断，以及这种变化以及LH峰释放是否可以用VP和/或NA受体激动剂诱导; 4）为了确定自动反馈是否抑制GABA合成，同时在LH峰之前刺激谷氨酸释放，我们将给予GABAB受体拮抗剂，并测量AVPV细胞体中GAD 67 mRNA水平的变化，以及接触LHRH神经元的双表型终末中囊泡GABA转运体和囊泡谷氨酸转运体的变化; 5）我们将确定VIP是否在LH峰的下午通过配体非依赖性激活PR来刺激cAMP依赖性NT基因表达。这些研究的结果可能为人类和非人类灵长类动物的检查提供新的目标，并可能导致更好地了解青春期，不育和下丘脑衰老的神经方面。此外，确定GABA神经元能够从抑制性神经传递切换到兴奋性传递将对理解其他脑区的GABA和GABA能“双重信号”具有重要意义。最后，这些研究的结果可能会提供关键的见解如何E2调节性别特异性神经发育，神经保护和神经退行性变等多种功能。

DESCRIPTION (provided by applicant): The long-term objective of this research is to determine how ovarian steroids trigger luteinizing hormone-releasing hormone (LHRH) and LH surge release, thereby inducing ovulation. In these studies, we will investigate mechanisms through which photoperiod and estrogen signals interact to regulate novel dual-phenotype GABA/glutamate neurons in the anteroventral periventricular nucleus (AVPV) of females. The specific aims of this proposal are: 1) To verify that GABA/glutamate neurons communicate directly with LHR neurons we will use anterograde and retrograde tracing and immunocytochemistry in rats and mice; 2) We will use electrophysiological studies in which LHRH neurons are identified by GGP expression to verify that AVPV GABA/Glutamate neurons release predominantly GABA during the morning and predominantly glutamate in the afternoon; 3) To determine whether vasopressin (VP) and/or noradrenaline (NA) trigger the midday rise in GABA release linked to the LH surge. We will examine the effects of specific VP and NA receptor antagonists on expression of a marker of GABA release, glutamic acid decarboxylase 67 (GAD67) mRNA. We will also determine whether changes in GAD67 mRNA levels are blocked when animals are placed in constant light and if such changes, as well as LH surge release, can be induced with VP and/or NA receptor agonists; 4) To determine whether autofeedback inhibits GABA synthesis while stimulating glutamate release prior to the LH surge, we will administer GABAB receptor antagonists and measure changes in GAD67 mRNA levels in AVPV cell bodies, as well as vesicular GABA transporter and vesicular glutamate transporter in dual-phenotype terminals contacting LHRH neurons; 5) We will determine whether VIP stimulates cAMP-dependent NT gene expression through ligand-independent activation of PR on the afternoon of the LH surge. The results of these studies may provide new targets for examination in humans and nonhuman primates and may lead to a better understanding of the neural aspects of puberty, infertility and hypothalamic aging. In addition, establishing that GABA neurons are able to switch from inhibitory neurotransmission to excitatory transmission will have important implications for understanding GABA and glutamatergic "dual-signaling" in other brain regions. Finally, the results of these studies may provide key insights into how E2 regulates such diverse functions as sex-specific neurodevelopment, neuroprotection and neurodegeneration.