Effect of diphtheritic demyelination on axonal transport in the sciatic nerve and subsequent muscle changes in the...

Chicken sciatic nerves undergo demyelination following intraneural injection of diphtheria toxin and subsequent atrophy of some muscular cells. Paresis occurs after one week and lasts approximately three weeks; at the height of the lesion C14-leucine was injected into the ventral horn cells of the spinal cord. The axonal transport of fast flowing labelled proteins was followed down the sciatic nerve axons and flow rates at two different times were measured. Muscle cells were stained for succinic dehydrogenase and ATPase; fibre diameters, total protein, and total radioactivity associated with the nerves were also measured. The results showed that the fast flowing labelled proteins accumulated at the demyelination site while the muscle cells supplied by these nerves showed reduction of fibre diameter and evidence of degeneration. Further studies are in progress on slow moving proteins and muscle cells.