MEMBRANE LEAKAGE IN SPINAL GANGLION NERVE-CELLS INDUCED BY EXPERIMENTAL WHIPLASH EXTENSION MOTION - A STUDY IN PIGS

Nerve cells in the cervical and upper thoracic spinal ganglia were exa mined for possible plasma membrane leakage, as revealed by their abili ty to exclude a dye-protein complex, after experimentally induced whip lash in a pig model system, The rationale for this approach is found i n the fact that the interstitium of spinal ganglia differs from most o ther parts of the nervous system in that it lacks a barrier, allowing blood constituents to gain access, The dye Evans blue, which rapidly c onjugates with blood proteins, is found in the interstitium of normal spinal ganglia after intravenous injection, but it is excluded from th e nerve cells and their enveloping satellite cells, In contrast, after a simulated whiplash extension trauma many of the nerve cells were st ained, reflecting the inability of their plasma membranes to exclude t he dye-protein complex, Morphometric measurements revealed that the hi ghest frequency of cellular dye uptake was observed in the C4-C7 spina l ganglia (mean 16-18%; range 5-27%), The blood-nerve barrier of the a djacent nerve fascicles remained intact, with rare exception, Several factors are considered to contribute to the induction of these cell ab normalities in the spinal ganglia after an experimentally induced, sim ulated whiplash trauma in this pig model system.