Candidates for photic entrainment pathways to the circadian clock via optic lobe neuropils in the Madeira cockroach
Candidates for photic entrainment pathways to the circadian clock via optic lobe neuropils in the Madeira cockroach
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DOI：
10.1002/cne.24844
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发表时间：
2020-01-20
影响因子：
2.5
通讯作者：
Stengl, Monika
中科院分区：
文献类型：
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作者：
Arnold, Thordis;Korek, Sebastian;Stengl, Monika
蟑螂的复眼是强制性的夹带马德拉蟑螂的生物钟，但其夹带途径的细胞性质是谜。采用多重标记免疫细胞化学，组织化学，和回填，我们寻找光夹带途径的副髓质（AME），昼夜节律钟的马德拉蟑螂。我们想知道感光末梢是否可以直接接触色素分散因子免疫反应（PDF-ir）昼夜节律起搏神经元与胞体在板（PDFLAs）或胞体旁边的AME（PDFMEs）。短的绿色敏感的感光神经元的复眼终止于层LA 1和LA 2，邻近PDFLAs和PDFMEs，在LA 3分支。长的紫外线敏感的复眼感光神经元终止于髓质层ME 2没有直接接触同侧PDFMEs，树枝状在ME 4。多个神经肽IR中间神经元在ME 4分支，连接AME到ME 2。以前认为板层器的眼外光感受器将终末送到副板层。在那里，它们与主要共定位PDF、FMRFamide和5-HT免疫反应性的PDFLA重叠，并与同侧和对侧PDFME的终末重叠。我们假设，在白天胆碱能激活最大的PDFME通过板器官光感受器保持PDF释放编排阶段的睡眠-觉醒周期。由于同侧PDFMEs表达兴奋性和对侧PDFMEs抑制性PDF自受体，因此昼夜PDF释放使两个PDF依赖性时钟电路处于反相。未来的实验将测试同侧PDFME是否是促进睡眠的早晨细胞，而对侧PDFME是否是促进活动的晚上细胞，通过板层器官眼外光感受器携带的最大PDFME维持稳定的反相。
The compound eye of cockroaches is obligatory for entrainment of the Madeira cockroach's circadian clock, but the cellular nature of its entrainment pathways is enigmatic. Employing multiple-label immunocytochemistry, histochemistry, and backfills, we searched for photic entrainment pathways to the accessory medulla (AME), the circadian clock of the Madeira cockroach. We wanted to know whether photoreceptor terminals could directly contact pigment-dispersing factor-immunoreactive (PDF-ir) circadian pacemaker neurons with somata in the lamina (PDFLAs) or somata next to the AME (PDFMEs). Short green-sensitive photoreceptor neurons of the compound eye terminated in lamina layers LA1 and LA2, adjacent to PDFLAs and PDFMEs that branched in LA3. Long UV-sensitive compound eye photoreceptor neurons terminated in medulla layer ME2 without direct contact to ipsilateral PDFMEs that arborized in ME4. Multiple neuropeptide-ir interneurons branched in ME4, connecting the AME to ME2. Before, extraocular photoreceptors of the lamina organ were suggested to send terminals to accessory laminae. There, they overlapped with PDFLAs that mostly colocalized PDF, FMRFamide, and 5-HT immunoreactivities, and with terminals of ipsi- and contralateral PDFMEs. We hypothesize that during the day cholinergic activation of the largest PDFME via lamina organ photoreceptors maintains PDF release orchestrating phases of sleep-wake cycles. As ipsilateral PDFMEs express excitatory and contralateral PDFMEs inhibitory PDF autoreceptors, diurnal PDF release keeps both PDF-dependent clock circuits in antiphase. Future experiments will test whether ipsilateral PDFMEs are sleep-promoting morning cells, while contralateral PDFMEs are activity-promoting evening cells, maintaining stable antiphase via the largest PDFME entrained by extraocular photoreceptors of the lamina organ.