Fig. 12. The effect of ecdysis-triggering hormone (ETH) injection on eclosion hormone-immunoreactivity (EH-IR) in the central nervous system (CNS) of intact or ligated pharate larvae. (A) Strong EH-IR in four ventro-medial (VM) cells, axons and arborizations in the brain of control pharate larva 12 h prior to ecdysis. (B—D) Four varicose axons of VM cells showed strong EH-IR along all ventral ganglia (B,C), connectives (D) and neurohaemal proctodeal nerves (E). (F—I) ETH-induced ecdysis behaviour of pharate larva (ligated between abdominal segments 5 and 6) was associated with strong EH-IR in the brain VM cells and axons (F) but a considerable reduction (arrows) or depletion of EH staining in axons of ventral ganglia (G,H). Accumulation of EH-IR was only found in four axons anterior to the ligated connective (I). (J) Depletion of EH-IR in proctodeal nerves of intact pharate larva 15 min after ETH-induced ecdysis behaviour. (K—N) Strong EH-IR in axons of abdominal ganglia (K,L), terminal nerve (M) and branching proctodeal nerves (N) in an ETH-injected isolated abdomen showing ecdysis movements for 15 min. Abbreviations: AG, abdominal ganglion; Con, connectives between AG5 and AG6; PN, proctodeal nerve; TG, thoracic ganglion; TN, terminal nerve. Scale bars, 100 µm (upper three rows) and 50 µm (lower two rows).

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