Ref ID : 78
Delves, C.J., Webb, R., and Howells, R.E.; Neurosecretory-like material in 3rd- and 4th-stage Dirofilaria immitis larvae (Nematoda: Filarioidea). Parasitology 99 Pt 1:99-104, 1989
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Notes
Phase-interference microscopic examination of the infective, post-infective 3rd-stage and 4th-stage larvae of Dirofilaria immitis has identified a single cell body in each of the paired lateral amphidial nerves which undergoes characteristic morphological change during the development from 3rd- to 4th-stage larvae. Acetaldehyde-fuchsin staining of worm sections revealed fuchsinophilic material in the precise location of the amphidial nerve-cell bodies observed by phase-interference microscopy. This material was found in 70% of infective larvae recovered from mosquitoes and in 100% of larvae recovered from micropore chambers 24 hr after implantation into BALB/C mice. In pre-moult larvae recovered at 42 hr (Experiment 1) and at 48 hr (Experiment 2) fuchsinophilic material was demonstrable, but no staining was observed in those larvae in which separation of the 3rd- and 4th-stage cuticles had occurred. No such material was observed in 4th-stage larvae recovered from chambers after 74 hr, and in these larvae the amphidial nerve-cell bodies were not discernible. These cytological observations are consistent with a cycle of elaboration and release of neurosecretion associated with moulting in D. immitis.