Non-synaptic inhibition between grouped neurons in an olfactory circuit

摘要

曾有人提出，一个神经元的“电活性”能影响rn与其没有相连的邻居的“电活性”，但这种所rn谓的“假突触效应”被普遍假设比较弱，相对rn来说被研究得很少。在这项研究中，JohnrnCarlson及其同事发现，果蝇的“嗅觉受体神rn经元”(ORNs)通过大的假突触信号相互通信，rn对嗅觉行为有显著影响。其中一个ORN的持rn久反应被其邻居的瞬时激发抑制。本文作者rn还发现，疟蚊“按蚊”中的一个对CO_2 敏感的rnORN可以被一个相邻ORN的激发所抑制，而rn果蝇的一个CO_2 神经元的侧向抑制能降低对rnCO_2 的行为反应。由于CO_2 是蚊子用来寻找人rn类宿主的一个关键提示，所以这项研究为昆rn虫控制提出了一个新手段。这些发现表明，rn“假突触效应”可能要比人们以前所意识到的rn更为普遍，尤其是在受限的“周围感觉腔”(如rn味蕾)中的神经元当中。%Diverse sensory organs, including mammalian taste buds and insect chemosensory sensilla, show a marked compart -mentalization of receptor cells; however, the functional impact of this organization remains unclear. Here we show that compartmentalized Drosophila olfactory receptor neurons (ORNs) communicate with each other directly. The sustained response of one ORN is inhibited by the transient activation of a neighbouring ORN. Mechanistically, such lateral inhibition does not depend on synapses and is probably mediated by ephaptic coupling. Moreover, lateral inhibition in the periphery can modulate olfactory behaviour. Together, the results show that integration of olfactory information can occur via lateral interactions between ORNs. Inhibition of a sustained response by a transient response may provide a means of encoding salience. Finally, a CO_2-sensitive ORN in the malaria mosquito Anopheles can also be inhibited by excitation of an adjacent ORN, suggesting a broad occurrence of lateral inhibition in insects and possible applications in insect control.