SCIATIC-NERVE STIMULATION INCREASES THE DEGREE OF HISTOPATHOLOGICAL DAMAGE IN LUMBOSACRAL SEGMENTS AFTER SHORT LASTING SPINAL-CORD ISCHEMIAIN RABBIT

To characterize the influence of primary afferent activation on the de velopment of histopathological changes in the spinal cord after revers ible ischemia, the left sciatic nerve was stimulated at the intensity of myelinated fibers before, during and for 1 h after 10 min of abdomi nal aortic ligation in halothane anesthetized rabbits. In control anim als, only 10 min of spinal cord ischemia or sciatic nerve stimulation was employed. One hour after reperfusion all animals were perfusion fi xed with 4% paraformaldehyde. Histopathological analysis using the sup pressive Nauta method revealed significantly higher number of argyroph ilic neurons in dorsal horns and in the intermediate zone in animals i n which spinal cord ischemia was combined with sciatic nerve stimulati on in comparison with the animals with spinal cord ischemia, but witho ut stimulation. These histopathological changes corresponded with sign s of irreversible damage analyzed on the ultrastructural level. Stimul ation of sciatic nerve, but without ischemia did not evoke any detecta ble neuronal changes. The data from the present study suggest that inc reased activity of spinal cord neurons evoked by peripheral nerve stim ulation can be an important factor in determining the extent of irreve rsible damage after short lasting ischemia.