Fine structure of a lepidopteran nervous system and its accessibility to peroxidase and lanthanum

摘要: The avascular ventral nerve cord of the moth, Manduca sexta, possesses an extensive dorsal mass connective tissue in which lie fibroblasts that produce a collagen-like protein. lateral and surfaces are ensheathed by acellular neural lamella. Beneath this lies layer microtubule-laden perineurial cells separated from one another at their peripheral borders lacunae containing electron-opaque material to attached hemi-desmosomes. Beyond these spaces, narrow intercellular clefts occur between interdigitating plasma membranes; then connected both gap tight junctions. axons beneath surrounded glia also contain many microtubules linked desmosomes When intact cords incubated horseradish peroxidase, reaction product is subsequently found within lamella as well cells, but not beyond level. Desheathed preparations, however, peroxidase cytoplasm exposed glial cells. Lanthanum penetrates lacunae, junctions adjacent no further. It therefore appears perineurium may be site restriction entry ions molecules, existence has been suggested previously electrophysiological investigations.