Patterns of Particle Movement in Nerve Fibres In Vitro-An Analysis by Photokymography and Microscopy

Tissue-cultured nerve fibres derived from 3 species of amphibian embryos were composed of bundles of neurites, when viewed by electron microscopy, and contained particles moving in both directions by saltations. Photokymographic analysis of ciné microscopy records taken with Zeiss differential interference optics demonstrated instantaneous particle velocities ranging from 0·15 to 1·8 μm s-1 (13–155 mm/day) in Rana pipiens cultures; 0·16–0·8 μm s-1 (14–74 mm/day) in Ambystoma tigrinum cultures and 0·6—2·25 μm s-1 (45—194 mm/day) in Xenopus laevis cultures. Measured pathlengths for particles saltations ranged from 4 to 63 μm. No correlations between particle velocity and pathlength were found.