Fahrbach S E, Truman J W
Department of Zoology, University of Washington, Seattle 98195.
J Neurobiol. 1987 Nov;18(6):497-508. doi: 10.1002/neu.480180603.
The emergence of the adult Manduca sexta moth is followed by the loss of almost half of this insect's abdominal motoneurons and interneurons (Truman, 1983). This programmed cell death completes the transformation of the nervous system of the caterpillar into that of the moth. The death of these neurons has been previously shown to be a response to an endocrine signal: the decline in ecdysteroids that occurs at the end of metamorphosis (Truman and Schwartz, 1984). Our current research is focussed on the regulation of the fate of a pair of identified motoneurons, the MN-12 cells, in the third abdominal ganglion. Isolation of this ganglion from anterior parts of the nervous system can prevent the death of these cells at the time when they would normally die in response to the decline in ecdysteroids. Transection of the ventral nerve cord at various levels revealed that the source of this regulatory "death signal" is the fused pterothoracic ganglion and that it is transmitted via the interganglionic connectives. We hypothesize that the factors mediating this effect may act in concert with the ecdysteroid decline to specify the exact time of death for individual neurons.
成年烟草天蛾羽化后，这种昆虫近半数的腹部运动神经元和中间神经元会死亡（杜鲁门，1983年）。这种程序性细胞死亡完成了毛虫神经系统向蛾神经系统的转变。此前已证明，这些神经元的死亡是对一种内分泌信号的反应：变态末期蜕皮类固醇的减少（杜鲁门和施瓦茨，1984年）。我们目前的研究重点是第三腹神经节中一对已确定的运动神经元MN - 12细胞命运的调控。将该神经节与神经系统前部隔离，可以防止这些细胞在正常情况下因蜕皮类固醇减少而死亡时死亡。在不同水平切断腹神经索表明，这种调节“死亡信号”的来源是融合的胸腹神经节，并且它是通过神经节间连接传递的。我们推测，介导这种效应的因素可能与蜕皮类固醇的减少协同作用，以确定单个神经元的确切死亡时间。
