Peptide Modulation of Physiology and Behavior

描述（由申请人提供）：我们的长期目标是体内神经回路中神经肽信号的机械解剖。我们已经使用了各种基因试剂在体内细胞特异性操作的三个B1类神经肽，其G蛋白偶联受体信号通过cAMP在苍蝇昼夜节律/睡眠控制电路：PDF（色素分散因子），DH 31（苍蝇降钙素同系物），和DH 44（苍蝇促肾上腺皮质激素释放因子（CRF）同系物）。已知PDF在生物钟神经元的一个子集中表达，并且对于调节苍蝇的日常节律和睡眠很重要。我们的初步研究现在表明，DH 31和DH 44在控制日常睡眠和活动模式方面具有不同的重要作用。苍蝇的休息和活动的双峰模式适应主要的季节条件：在冬季，大多数活动在晚上（以避免夜晚的寒冷），而在夏季，大多数活动在早上（以避免白天的炎热）。我们的初步研究表明，PDF分泌神经元自身所拥有的PDF受体（PDFR）的自分泌激活增加是从晚上到早上活动平衡的季节性变化的基础。我们将使用各种遗传工具来检验自分泌PDFR激活通过调节PDF分泌本身的日常模式来诱导昼夜节律网络特性的这种可塑性变化的假设。最近的研究表明，非PDF分泌时钟细胞的一个特定子集是这种PDF信号所需的接收者。我们的初步研究表明，在这个子集中的许多神经元表达DH 31，和缺乏PDF的果蝇一样，缺乏DH 31的突变果蝇表现出严重的昼夜活动减弱。此外，PDF分泌的时钟神经元本身具有DH 31受体（DH 31 R），从而提出了这样的假设，即PDF分泌和DH 31分泌的时钟神经元之间的相互反馈回路驱动早晨活动。我们将使用各种遗传工具来验证这一假设。我们的初步研究表明，DH 44-CRF的苍蝇同源物-在大脑间部的神经元亚群中高水平表达，下丘脑的苍蝇同源物。此外，我们已经进行了初步的行为遗传筛选，这表明-对于哺乳动物CRF -DH 44信号传导到中枢脑神经元减少总睡眠量并增加睡眠碎片。基于这些初步发现，我们将使用各种遗传工具来识别负责调节睡眠的特定DH 44受体表达神经元。

DESCRIPTION (provided by applicant): Our long-term goal is the mechanistic dissection of neuropeptide signals in neural circuits in vivo. We have used a variety of genetic reagents for in vivo cell-specific manipulation of three Class B1 neuropeptides whose G protein-coupled receptors signal through cAMP in fly circadian/sleep control circuits: PDF (Pigment Dispersing Factor), DH31 (fly calcitonin homologue), and DH44 (fly corticotropin releasing factor (CRF) homologue). PDF is already known to be expressed in a subset of circadian clock neurons and to be important for regulating fly daily rhythms and sleep. Our preliminary studies now suggest distinct important roles for DH31 and DH44 in controlling daily patterns of sleep and activity. Flies adapt their bimodal crepuscular pattern of rest and activity to prevailing seasonal conditions: in the winter most activity is in the evening (to avoid the chill of night), while in the summer most activity is in the morning (to avoid the heat of day). Our preliminary studies suggest that increased autocrine activation of PDF receptors (PDFR) possessed by the PDF-secreting neurons themselves underlies this seasonal shift in the balance of activity from evening to morning. We will use various genetic tools to test the hypothesis that autocrine PDFR activation induces this plastic change in circadian network properties by modulating the daily pattern of PDF secretion itself. Recent studies implicate a particular subset of non-PDF-secreting clock cells as the required recipients of this PDF signal. Our preliminary studies indicate that many of the neurons in this subset express DH31, and that - like flies lacking PDF - mutant flies lacking DH31 exhibit severely blunted circadian morning activity. Furthermore, PDF-secreting clock neurons themselves possess DH31 receptors (DH31R), thus suggesting the hypothesis that a reciprocal feedback loop between PDF-secreting and DH31-secreting clock neurons drives morning activity. We will use various genetic tools to test this hypothesis. Our preliminary studies show that DH44-the fly homologue of CRF-is expressed at high levels in a subset of neurons in the pars intercerebralis, fly homologue of the hypothalamus. Furthermore, we have performed a preliminary behavioral genetic screen suggesting that - as for mammalian CRF - DH44 signaling to central brain neurons decreases total sleep amount and increases sleep fragmentation. Based on these preliminary findings, we will use a variety of genetic tools to identify the specific DH44 receptor-expressing neurons responsible for the regulation of sleep.