Miles CI, Booker R
Department of Neurobiology and Behavior, Cornell University, Seeley G. Mudd Hall, Ithaca, NY 14853, USA.
J Exp Biol. 1998 Jun;201 (Pt 11):1785-98. doi: 10.1242/jeb.201.11.1785.
We have examined the musculature and motor patterns of the foregut and the role of the frontal ganglion in the adult moth Manduca sexta. During adult development, the structure of the foregut changes from a simple straight tube to a pump consisting of a flexible-roofed chamber or cibarium, with dilator muscles that raise the roof to draw in fluids and a compressor to push it down and force the fluid down the thin-walled esophagus. The frontal ganglion drives the activity of this cibarial pump during feeding, which is triggered by the application of sucrose solution or water to the proboscis. The feeding motor pattern consists of coupled bursts of the pump dilators and shorter-duration, high-frequency bursts of spikes from the pump compressor. The pump is also activated at the adult molt. At this time, it is used both before the moth emerges from the pupal case for swallowing molting fluid and again after emergence for swallowing air. These behaviors are important for eclosion and are necessary for the expansion of the wings after eclosion. Their motor patterns are similar to the feeding program. Up to 24 h before adult ecdysis, this motor pattern can be triggered by the peptide eclosion hormone. The other eclosion-related peptide, Manduca sexta eclosion-triggering hormone, does not appear to trigger activity of the cibarial pump.
我们研究了成年烟草天蛾前肠的肌肉组织和运动模式，以及额神经节在其中的作用。在成虫发育过程中，前肠结构从简单的直管转变为一个泵，该泵由一个顶部可灵活活动的腔室即食窦组成，有用于抬起顶部以吸入液体的扩张肌和用于向下推动并迫使液体通过薄壁食管的压缩肌。在取食期间，额神经节驱动这个食窦泵的活动，取食由向喙部施加蔗糖溶液或水触发。取食运动模式由泵扩张肌的耦合脉冲以及泵压缩肌的持续时间较短的高频脉冲组成。该泵在成虫蜕皮时也会被激活。此时，在蛾子从蛹壳中羽化出来之前，它用于吞咽蜕皮液，在羽化之后又用于吞咽空气。这些行为对羽化很重要，并且是羽化后翅膀展开所必需的。它们的运动模式与取食程序相似。在成虫蜕皮前长达24小时，这种运动模式可由肽类羽化激素触发。另一种与羽化相关的肽，即烟草天蛾羽化触发激素，似乎不会触发食窦泵的活动。
