The role of myoinhibitory peptides (MIPs) in the circadian system of the Madeira cockroach Rhyparobia maderae

马德拉蟑螂Rhyparobia maderae是一种已建立的昼夜节律研究模式生物。我们确定了与相关的色素分散因子免疫反应（PDF-IR）神经元作为昼夜节律起搏中心控制昼夜运动活动节律的副髓质（AME）。AME神经元富含部分共定位的神经肽。例如，PDF和肌抑制肽（MIP）共定位于两个神经元中。MIP在蟑螂钟中的功能尚不清楚。性肽受体（SPR）是果蝇中的一种MIP受体，它控制着果蝇从非交配状态到交配状态的生理/行为转换。通过转录组分析，我们先前在R.马德拉酒使用异源表达研究结合BRET测定，我们想要检查其功能。在Ca2+成像分析结合免疫细胞化学，与应用MIP的原代细胞培养的AME，我们将表征MIP信号在蟑螂时钟。 我们希望确定MIP在生物钟中的信号转导级联，并鉴定MIP敏感的AME细胞。此外，在结合免疫细胞化学的行为测定中，我们将研究MIP信号传导和交配/交配后行为是否相互调节。我们期望深入了解MIP的具体功能，以及神经肽在昼夜节律系统和昆虫大脑中功能的一般原理。

The Madeira cockroach Rhyparobia maderae is an established model organism for circadian rhythm research. We identified the accessory medulla (AME) with associated pigment-dispersing factor-immunoreactive (PDF-ir) neurons as circadian pacemaker center controlling circadian locomotor activity rhythms. The AME neurons are abundant in partly colocalized neuropeptides. For example, PDF and myoinhibitory peptide (MIP) are colocalized in two neurons. The function of MIP in the cockroach clock is not known. In Drosophila melanogaster the sex peptide receptor (SPR) is a MIP receptor which controls a physiological/behavioral switch from the non-mated to the mated state. With transcriptome analysis we previously identified a SPR candidate in R. maderae. Using heterologous expression studies combined with BRET assays we want to examine its function. In Ca2+-imaging assays combined with immunocytochemistry, with application of MIPs to primary cell cultures of the AME we will characterize MIP signaling in the cockroach clock. We want to determine signal transduction cascades of MIP in the circadian clock and identify MIP-sensitive AME cells. Furthermore, in behavioral assays combined with immunocytochemistry we will examine whether MIP-signaling and mating/post-mating behaviors regulate each other. We expect to gain insights into specific functions of MIPs and into general principles of neuropeptide function in the circadian system and in insect brains in general.