Fig. 9. In vitro treatment of the isolated central nervous system with 20-hydroxyecdysone followed by ETH application 24–28 h later. (A) This treatment induced strong pre-ecdysis burst patterns in three nerve cords. Note the synchronous bursts in dorsal nerves (D) which alternate with synchronous bursts in ventral nerves (V) of this nerve cord. (B) Most nerve cords showed attenuation of pre-ecdysis bursts, but these preparations displayed ecdysis bursts (C) after incubation with ETH for 40–55 min. Note that bursts from adjacent ganglia of this nerve cord are delayed, which is characteristic of peristaltic ecdysis movements. Dorsal (D) and ventral (V) nerves of abdominal ganglia 4, 5, 6 (AG4,5,6)