Non‐specific cholinesterase activity of the developing peripheral nerves and its possible function in cells in intimate contact with growing axons of chick embryo

Abstract

The results presented here demonstrate non-specific cholinesterase (nChE) activity in the developing peripheral nerves of chick embryos at stages 25-26 according to Hamburger and Hamilton (1951, J. Morphol. 88, 49-92). Under the light microscope the use of simultaneous staining for nChE activity and silver proteinate impregnation revealed the axons to be surrounded by cells exhibiting nChE activity in the main nerve trunks and in the growing tips of nerves. Nerve branches arising from the main nerve trunks contained cells with positive reaction for nChE activity, too. Electron-dense particles of the reaction product indicating nChE activity were found in the rough endoplasmic reticulum and in the perinuclear envelope of cells in close contact with growing nerve fibers and their growth cones. The same distribution of nChE activity was found in cells which were located near to nerve fasciculi but without direct contact with axons. Surprisingly, the cells in close contact with axons and their growth cones exhibited the end product of nChE activity in the outer part of their plasma membrane. The cells enveloping axons within the nerve trunks were apparently Schwann cells, while those around the growth cones at nerve tips could be identified as Schwann cells and/or mesenchymal cells of the hindlimb. The nChE reaction product was also detected in the axolemma of nerve fibers and their growth cones. The distribution of nChE activity in the developing peripheral nerves of chick embryos suggests that these molecules may influence the process of axonal elongation and locomotion. Several possible mechanisms of nChE action on growing axons can be presumed: (i) intracellular Ca2+ level regulation; (ii) providing an adhesive substrate; and (iii) butyrate production affecting the cell metabolism and the distribution of neurotubules and neurofilaments. It is also assumed that nChE molecules are involved in the interactions of nerve fibers with Schwann cells and/or mesenchymal cells as well as in interneuronal interactions.

Origin of cells in contact with the growth cones of embryonal peripheral nerves and histochemical detection of nonspecific cholinesterase activity in quail‐chick and chick‐quail chimeras

“…Our results demonstrate at the electron microscopic level that the growth cones in the hindlimb of chimera embryos are in contact with both Schwann cell progenitors and mesenchymal cells of the limb bud. These findings correspond probably with a dynamic process of the axon growth as reported previously (Dubovy and Haninec, 1990).…”

“…Excluding classic adhesive molecules the growth cones may be influenced by another type of molecules, e.g., enzymes. This concept was proposed in our previous study for the nChE molecules (Dubovy and Haninec, 1990). Bon et al (1988) and Massoulie and Bonn (1990) gave cogent evidence that some molecules of cholinesterase carry the glycosidic epitope characteristic of ad-their neural crest provenance (Harrison, 1908;Le-Douarin, 1982).…”

Association of butyrylcholinesterase K variant with cholinesterase-positive neuritic plaques in the temporal cortex in late-onset Alzheimer's disease

“…Our third hypothesis concerns the proposed role of BChE in neurite guidance and growth (Dubový and Haninec 1990;Layer et al 1988Layer et al , 1993. This process may be mediated by BChE itself, by a non-enzymic mechanism (Layer et al 1993).…”

A Hidden Retinal Regenerative Capacity from the C Ciliary Margin is Reactivated In Vitro, that is Accompanied by Down‐regulation of Butyrylcholinesterase

“…Layer et al, 1990). Subsequent development very much resembles the development occumng between days E6 and El0 in ovo (Diitting et al, 1983). During that time cells become organized in cell columns and in three distinct layers.…”