Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, People's Republic of China.
Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, People's Republic of China
Proc Natl Acad Sci U S A. 2019 Apr 2;116(14):7107-7112. doi: 10.1073/pnas.1819261116. Epub 2019 Mar 14.
Feeding is vital for animal survival and is tightly regulated by the endocrine and nervous systems. To study the mechanisms of humoral regulation of feeding behavior, we investigated serotonin (5-HT) and octopamine (OA) signaling in , which uses pharyngeal pumping to ingest bacteria into the gut. We reveal that a cross-modulation mechanism between 5-HT and OA, which convey feeding and fasting signals, respectively, mainly functions in regulating the pumping and secretion of both neuromodulators via ADF/RIC/SIA feedforward neurocircuit (consisting of ADF, RIC, and SIA neurons) and ADF/RIC/AWB/ADF feedback neurocircuit (consisting of ADF, RIC, AWB, and ADF neurons) under conditions of food supply and food deprivation, respectively. Food supply stimulates food-sensing ADFs to release more 5-HT, which augments pumping via inhibiting OA secretion by RIC interneurons and, thus, alleviates pumping suppression by OA-activated SIA interneurons/motoneurons. In contrast, nutrient deprivation stimulates RICs to secrete OA, which suppresses pumping via activating SIAs and maintains basal pumping and 5-HT production activity through excitation of ADFs relayed by AWB sensory neurons. Notably, the feedforward and feedback circuits employ distinct modalities of neurosignal integration, namely, disinhibition and disexcitation, respectively.
进食对于动物的生存至关重要，它受到内分泌和神经系统的严格调节。为了研究体液调节进食行为的机制，我们研究了 中血清素（5-HT）和章鱼胺（OA）信号转导， 利用咽部抽吸将细菌吸入肠道。我们揭示了 5-HT 和 OA 之间的交叉调节机制，这两种神经递质分别传递进食和禁食信号，主要通过 ADF/RIC/SIA 前馈神经回路（由 ADF、RIC 和 SIA 神经元组成）和 ADF/RIC/AWB/ADF 反馈神经回路（由 ADF、RIC、AWB 和 ADF 神经元组成）调节两种神经调质的抽吸和分泌，分别在食物供应和食物剥夺的条件下。食物供应刺激食物感知 ADF 释放更多的 5-HT，通过抑制 RIC 中间神经元释放 OA，从而增强抽吸，减轻由 OA 激活的 SIA 中间神经元/运动神经元引起的抽吸抑制。相反，营养缺乏刺激 RIC 分泌 OA，通过激活 SIAs 抑制抽吸，并通过 AWB 感觉神经元传递的兴奋维持基础抽吸和 5-HT 产生活动。值得注意的是，前馈和反馈回路采用了不同的神经信号整合模式，分别是去抑制和去兴奋。
