Electrophysiology of zona incerta neurons

描述（由申请人提供）：间脑的未定带（ZI）与其他脑区域有广泛的联系，并参与多种功能，如控制内脏活动、体温调节、唤醒和运动活动。尽管它的重要功能，它是大脑的最欠研究的区域之一，没有研究的细胞和突触的电生理特性的ZI神经元已报道到目前为止。维持体温是哺乳动物体内能量平衡的核心，因为它代表了生物体能量消耗的主要部分。它是由视前区/下丘脑前部（PO/AH）的神经元直接或间接投射到吻侧核控制的。 苍白缝解剖和功能的证据清楚地表明，从视前区，温度调节中心，ZI神经元的投影。结合逆行免疫染色实验表明，投射到ZI的视前神经元是肽能的。ZI神经元投射到苍白中缝，因此它们可以代表视前产热输出到控制热效应过程的脑干神经元的中继。我们的总体假设是，ZI GABA能神经元介导的肽能调节的温度调节的视前神经元。初步数据表明，ZI神经元表达这些神经肽的受体。我们还发现，温度调节神经肽通过激活内向电流来兴奋ZI GABA能神经元，并且它们增加细胞内Ca浓度。我们的初步数据还表明，投射到ZI GABA能神经元的视前神经元是肽能的。我们计划在切片中识别GABA能和多巴胺能ZI神经元，并研究它们的放电和突触特征以及参与体温调节的神经肽对它们的调制，然后进行单细胞RT/PCR分析以确定这些受体的表达模式（Sp. aim 1）。一组实验将利用来自中缝苍白球的逆行标记来识别投射到该区域的ZI神经元。 通过使用药理学工具，钙成像，电生理学和单细胞RT-PCR，我们将研究参与神经肽对ZI神经元（Sp.Aim2）的作用的信号通路和离子电导。在Sp目的3中，我们将使用遥测和局部输注药物来确定AVP和神经降压素信号传导在ZIv体温调节中的作用。研究ZI神经元中温度调节肽激活的细胞机制和信号通路可能为开发低温剂和控制能量稳态提供中枢药理学靶点。总之，在这项研究中，我们将解决神经生理学的基本和未探索的方面，并开始为理解扰动肽能信号对疾病的作用奠定基础。

DESCRIPTION (provided by applicant): Zona incerta (ZI) of the diencephalon has extensive connections with other brain regions and has been involved in several functions such as controlling visceral activity, thermoregulation, arousal and locomotor activity. In spite of its important functions it is one of the most understudied regions of the brain and no studies of the cellular and synaptic electrophysiological properties of ZI neurons have been reported so far. Maintenance of body temperature is central to energy homeostasis in mammals because it represents a major part of the energy expenditure of the organism. It is controlled by neurons of the preoptic area/ anterior hypothalamus (PO/AH) that project directly or indirectly to the rostral raphe pallidus. Anatomical and functional evidence clearly indicate a projection from the preoptic area, the thermoregulatory center, to ZI neurons. Combined retrograde immunostaining experiments have revealed that preoptic neurons projecting to ZI are peptidergic. ZI neurons project to the raphe pallidus and thus they can represent a relay of the preoptic thermogenic output to the brainstem neurons controlling thermoeffector processes. Our overarching hypothesis is that ZI GABAergic neurons mediate the peptidergic modulation of thermoregulation by preoptic neurons. Preliminary data indicate that ZI neurons express receptors for these neuropeptides. We have also found that thermoregulatory neuropeptides excites ZI GABAergic neurons by activating inward currents and that they increase intracellular Ca concentrations. Our preliminary data also show that preoptic neurons projecting to ZI GABAergic neurons are peptidergic. We plan to identify both GABAergic and glutamatergic ZI neurons in slices and study their firing and synaptic characteristics as well as their modulation by neuropeptides involved in thermoregulation, followed by single cell RT/PCR analysis to determine the expression patterns for these receptors (Sp. aim1). A set of experiments will utilize retrograde labeling from the raphe pallidus to identify ZI neurons projecting to that area. By employing pharmacological tools, Ca imaging, electrophysiology and single cell RT-PCR we will then study the signaling pathways and the ion conductances involved in the neuropeptides' actions on ZI neurons (Sp. Aim2). In Sp Aim 3 we will determine using telemetry and local infusions of pharmacological agents the role of AVP and neurotensin signaling in the ZIv in thermoregulation. Studying the cellular mechanisms and signaling pathways activated by thermoregulatory peptides in ZI neurons may provide central pharmacological targets for the development of hypothermic agents and for the control of energy homeostasis. In summary in this study we will address fundamental and unexplored aspects of neurophysiology and start to lay the groundwork for understanding the role of perturbed peptidergic signaling to disease.