Zhang Wei, Yan Zhiqiang, Li Bingxue, Jan Lily Yeh, Jan Yuh Nung
Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States.
State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China.
Elife. 2014 Oct 30;3:e03293. doi: 10.7554/eLife.03293.
Defecation allows the body to eliminate waste, an essential step in food processing for animal survival. In contrast to the extensive studies of feeding, its obligate counterpart, defecation, has received much less attention until recently. In this study, we report our characterizations of the defecation behavior of Drosophila larvae and its neural basis. Drosophila larvae display defecation cycles of stereotypic frequency, involving sequential contraction of hindgut and anal sphincter. The defecation behavior requires two groups of motor neurons that innervate hindgut and anal sphincter, respectively, and can excite gut muscles directly. These two groups of motor neurons fire sequentially with the same periodicity as the defecation behavior, as revealed by in vivo Ca(2+) imaging. Moreover, we identified a single mechanosensitive sensory neuron that innervates the anal slit and senses the opening of the intestine terminus. This anus sensory neuron relies on the TRP channel NOMPC but not on INACTIVE, NANCHUNG, or PIEZO for mechanotransduction.
排便使身体能够排出废物，这是动物生存的食物加工过程中的一个重要步骤。与对摄食（其必然对应行为）的广泛研究相比，排便直到最近才受到少得多的关注。在本研究中，我们报告了对果蝇幼虫排便行为及其神经基础的表征。果蝇幼虫表现出具有刻板频率的排便周期，涉及后肠和肛门括约肌的顺序收缩。排便行为需要两组分别支配后肠和肛门括约肌的运动神经元，它们可以直接刺激肠道肌肉。如体内钙成像所示，这两组运动神经元以与排便行为相同的周期性顺序放电。此外，我们鉴定出一个单一的机械敏感感觉神经元，它支配肛门裂隙并感知肠末端的开口。这个肛门感觉神经元在机械转导中依赖于TRP通道NOMPC，而不依赖于INACTIVE、NANCHUNG或PIEZO。
