Fine Structure of the Central Nervous System of 'Dermacentor variabilis' (Say), 'Amblyomma americanum' (L.), and 'Argas arboreus' Kaiser, Hoogstraal and Kohls (Ixodoidea).

摘要

The central nervous system of unfed male Dermacentor variabilis (Say) and female Amblyomma americanum (L.) (Ixodidae), and female Argas (Persicargas) arboreus Kaiser, Hoogstraal, and Kohls (Argasidae) was studied by light microscopy using open sections stained with Azure II and PAS, and by transmission electron microscopy. The fused central nervous system is enclosed within a periganglionic blood sinus and penetrated by the esophagus. This system consists of an outer neural lamella containing layers of homogeneous finely granula material and periodically cross-banded collagenous fibrils, a cortex of perineurium, glial cells, at least 3 neuronal types, and an inner neuropile of nerve fibers (axons and dendrites) partially ensheathed by glial processes. Large intracellular spaces occur in perineural glial cells in A. arboreus, but heavy glycogen deposits are observed in perineurium of D. variabilis and A. americanum. The fine structure of the nervous tissue and of a peripheral nerve is compared to that of insects and mites as a basis for investigating structural changes in ticks infected by viruses and rickettsias. (Author)