Takizawa Eiji, Komatsu Akira, Tsujimura Hidenobu
Developmental Biology, Tokyo University of Agriculture and Technology, Fuchu-Shi, Tokyo, Japan.
Zoolog Sci. 2007 May;24(5):504-13. doi: 10.2108/zsj.24.504.
In insects, four types of motoneurons have long been known, including fast motoneurons, slow motoneurons, common inhibitory motoneurons, and DUM neurons. They innervate the same muscle and control its contraction together. Recent studies in Drosophila have suggested the existence of another type of motoneuron, the common excitatory motoneuron. Here, we found that shakB-GAL4 produced by labels this type of motoneuron in Drosophila larvae. We found that Drosophila larvae have two common excitatory motoneurons in each abdominal segment, RP2 for dorsal muscles and MNSNb/d-Is for ventral muscles. They innervate most of the internal longitudinal or oblique muscles on the dorsal or ventral body wall with type-Is terminals and use glutamate as a transmitter. Electrophysiological recording indicated that stimulation of the RP2 axon evoked excitatory junctional potential in a dorsal muscle.
长期以来，人们已知昆虫中有四种类型的运动神经元，包括快运动神经元、慢运动神经元、共同抑制性运动神经元和背单胺能神经元。它们支配同一块肌肉并共同控制其收缩。最近在果蝇中的研究表明存在另一种类型的运动神经元，即共同兴奋性运动神经元。在此，我们发现由shakB-GAL4标记产生的这种类型的运动神经元存在于果蝇幼虫中。我们发现果蝇幼虫每个腹节中有两个共同兴奋性运动神经元，背侧肌肉的RP2和腹侧肌肉的MNSNb/d-Is。它们以I型终末支配背侧或腹侧体壁上的大部分内部纵肌或斜肌，并使用谷氨酸作为递质。电生理记录表明，刺激RP2轴突可在背侧肌肉中诱发兴奋性接头电位。
