Gal Ram, Libersat Frederic
Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, PO Box 653, Be'er Sheva 84105, Israel.
Curr Biol. 2008 Jun 24;18(12):877-82. doi: 10.1016/j.cub.2008.04.076. Epub 2008 Jun 5.
The parasitoid wasp A. compressa hunts cockroaches as a live food supply for its offspring. The wasp selectively injects venom into the cerebral ganglia of the prey to induce long-term hypokinesia [1-5], during which the stung cockroach, although not paralyzed, does not initiate spontaneous walking and fails to escape aversive stimuli. This allows the wasp to grab the cockroach by the antenna and walk it to a nest much like a dog on a leash. There, the wasp lays an egg on the prey, seals the nest, and leaves. The stung cockroach, however, does not fight to escape its tomb but rather awaits its fate, being consumed alive by the hatching larva over several days. We investigated whether the venom-induced hypokinesia is a result of an overall decrease in arousal or, alternatively, a specific decrease in the drive to initiate or maintain walking. We found that the venom specifically affects both the threshold for the initiation and the maintenance of walking-related behaviors. Nevertheless, the walking pattern generator itself appears to be intact. We thus report that the venom, rather than decreasing overall arousal, manipulates neuronal centers within the cerebral ganglia that are specifically involved in the initiation and maintenance of walking.
寄生黄蜂压缩阿氏黄蜂捕食蟑螂，作为其后代的活体食物来源。黄蜂会选择性地将毒液注入猎物的脑神经节，以诱发长期运动减退[1 - 5]，在此期间，被蜇的蟑螂虽然没有瘫痪，但不会主动行走，也无法躲避厌恶刺激。这使得黄蜂能够抓住蟑螂的触角，像牵狗一样把它带到巢穴。在那里，黄蜂在猎物身上产卵，封住巢穴，然后离开。然而，被蜇的蟑螂不会挣扎逃脱它的坟墓，而是等待命运的降临，在几天内被孵化出的幼虫活活吃掉。我们研究了毒液诱导的运动减退是由于整体觉醒水平下降，还是由于启动或维持行走的驱动力特异性下降。我们发现，毒液特异性地影响启动和维持与行走相关行为的阈值。然而，行走模式发生器本身似乎是完好的。因此，我们报告称，毒液并非降低整体觉醒水平，而是操纵脑神经节内专门参与启动和维持行走的神经中枢。
