摘要系留果蝇可以研究飞行控制的生物力学和电生理学。我们在间接飞行肌肉(背侧纵向肌肉,DLMa)与通过麦克风信号对机翼拍频(WBF)的声学分析相结合。直接和间接飞行肌肉的同时电生理记录在技术上具有挑战性;然而,WBF被认为反映在与直飞肌肉子集的尖峰活动的一对一关系中,包括肌肉M1B。因此,我们的方法能够对神经支配直接和间接飞行肌肉子集的运动神经元电活动的时间特征的变化进行系统的突变分析。这里,我们报告了特定离子通道中断对肌源性DLMs(在〜5Hz激发)和相应的WBF(〜200Hz)的尖峰活动的影响。我们检查了以下基因的突变体:1)电压门控Ca(2)通道(杂音,cac),2)Ca(2+)激活K(+)通道(慢戳,slo),和3)电压门控K(+)通道(振动筛,Sh)及其辅助亚基(运动亢进,香港和颤抖,qvr)。我们发现,在cac和slo突变体中,响应吹气的飞行开始都受到了严重破坏。然而,一旦启动,slo飞行基本上没有改变,而cac显示DLM放电率和WBF中断。Sh,香港,qvr突变体能够保持正常的DLM发射速率,尽管增加了WBF。值得注意的是,Hk和qvr编码的辅助子单元中的缺陷可能会导致不同的后果,也就是说,中断的DLM发射节律,在Sh中没有观察到。我们对直接和间接飞行肌肉活动的突变分析表明,两种运动活动模式可能会被特定的离子通道突变独立地修饰,这种方法可以扩展到其他双翅目物种和额外的运动程序,如电惊厥刺激引起的癫痫发作。
Abstract Tethered flies allow studies of biomechanics and electrophysiology of flight control. We performed microelectrode recordings of spikes in an indirect flight muscle (the dorsal longitudinal muscle, DLMa) coupled with acoustic analysis of wing beat frequency (WBF) via microphone signals. Simultaneous electrophysiological recording of direct and indirect flight muscles has been technically challenging; however, the WBF is thought to reflect in a one-to-one relationship with spiking activity in a subset of direct flight muscles, including muscle m1b. Therefore, our approach enables systematic mutational analysis for changes in temporal features of electrical activity of motor neurons innervating subsets of direct and indirect flight muscles. Here, we report the consequences of specific ion channel disruptions on the spiking activity of myogenic DLMs (firing at ∼5 Hz) and the corresponding WBF (∼200 Hz). We examined mutants of the genes enconding: 1) voltage-gated Ca(2+) channels (cacophony, cac), 2) Ca(2+)-activated K(+) channels (
slowpoke, slo), and 3) voltage-gated K(+) channels (Shaker, Sh) and their auxiliary subunits (Hyperkinetic, Hk and quiver, qvr). We found flight initiation in response to an air puff was severely disrupted in both cac and slo mutants. However, once initiated, slo flight was largely unaltered, whereas cac displayed disrupted DLM firing rates and WBF. Sh, Hk, and qvr mutants were able to maintain normal DLM firing rates, despite increased WBF. Notably, defects in the auxiliary subunits encoded by Hk and qvr could lead to distinct consequences, that is, disrupted DLM firing rhythmicity, not observed in Sh. Our mutant analysis of direct and indirect flight muscle activities indicates that the two motor activity patterns may be independently modified by specific ion channel mutations, and that this approach can be extended to other dipteran species and additional motor programs, such as electroconvulsive stimulation-induced seizures.