Chemical and morphological studies on garfish peripheral nerves

Abstract

Gangliosides were extracted, separated by thin layer chromatography, and quantitated in three cranial nerves of the garfish (Lepisosteus osseus): the completely unmyelinated olfactory nerve (OLF), and two nerves composed of both myelinated and unmyelinated fibers, viz., the main trunk of the maxillary nerve (MAX) and a branch of the maxillary nerve (BR‐MAX). Morphological studies on each of these nerves were done to verify that the OLF had been excised free of any contamination from the accompanying myelinated BR‐MAX, to aid in the interpretation of the biochemical findings, and to clarify the nature of the OLF supporting cell. The chief chemical findings were (1) documentation of the presence of gangliosides in nerves previously thought not to contain them, (2) demonstration that gangliosides can be associated with unmyelinated nerves, (3) demonstration of a greater proportion of one simple ganglioside (G‐6) in the OLF but greater proportions of two complex gangliosides (G‐2 and G‐O) in the MAX and BR‐MAX, and (4) that either GM4 or a variant of the GM3 is present in OLF. The morphological findings with respect to the difficulty of ascribing only peripheral nervous system characteristics to the OLF supporting cell are discussed in relation to the ganglioside band chromatographing slightly ahead of GM4 in the OLF.