DISTRIBUTION OF ACETYLCHOLINESTERASE IN THE CENTRAL-NERVOUS-SYSTEM OFHARVESTMEN (ARACHNIDA, OPILIONIDA)

Enzyme histochemical technique (Gomori and Koelle methods, reaction pr oduct development according to Lewis) was applied on 10 mu m frozen se ctions of formalin-fixed material to demonstrate the distribution of a cetylcholinesterase in the central nervous system (CNS) of harvestmen (Opilionida: Phalangiidae). Distinctly positive reactions were confine d to the neuropil, showing strong staining especially in protocerebral brain centres (optic lobes, cerebral ganglia), the cheliceral ganglia (stomodeal bridge, afferent tracts), and the connective ring systems of the subesophageal nerve mass. The results obtained are discussed wi th regard to central coordinative functions of the respective brain pa rts. (C) 1998 Elsevier Science Ireland Ltd. Ail rights reserved.