CHANGES IN THE ULTRASTRUCTURE OF SURVIVING DISTAL SEGMENTS OF SEVEREDAXONS OF THE ROCK LOBSTER

Peripheral axons of lobsters can survive for many months after axotomy . We have investigated the structural and ultrastructural changes seen after axotomy using confocal microscopy and electron microscopy. Whil e the proximal stump had a normal appearance, the distal part of the c ut axon became lobulated, and glial cells penetrated the original glia l tube (axon tube) in which the axon normally runs. The changes procee ded from the cut end towards the muscle. As time elapsed, the axon tub e seemed to be filled with glial cells, but interposed small profiles of the original axon could be identified by injection of a fluorescent dye into the axon. The glial cells send cytoplasmic projections deep into folds of the axolemma, and nuclei were found at the end of these long processes. Proliferation of glial cells was also seen.