Dynorphin is a
neuropeptide that is present in high quantities in the dorsal horn of the spinal cord. The
peptide is actively involved in
pain processing pathways. However, its involvement in
spinal cord injury is not well known. Alteration in
dynorphin immunoreactivity occurs following a focal
trauma to the rat spinal cord. Infusion of
dynorphin into the intrathecal space of the cord results in
ischemia, cell damage and abnormal motor function.
Antibodies to
dynorphin when injected into the intrathecal space of the spinal cord following
trauma improve motor recovery, reduce
edema and cell changes. However, influence of
dynorphin on
trauma induced alteration in spinal cord bioelectrical activity is still not known. Spinal cord evoked potentials (SCEP) are good
indicator of spinal cord pathology following
trauma. Therefore, in present investigation, influence of
dynorphin antibodies on
trauma induced changes in SCEP were examined in our rat model. In addition, spinal cord
edema formation, microvascular permeability disturbances and cell injury were also investigated. Our results show that topical application of
dynorphin antiserum (1 : 200) two min before injury markedly attenuated the SCEP changes immediately after injury. In the antiserum treated animals, a significant reduction in the microvascular permeability,
edema formation and cell injury was observed in the traumatised spinal cord. These observations suggest that (i).
dynorphin is involved in the altered bioelectrical activity of the spinal cord following
trauma, (ii). the
peptide actively participates in the pathophysiological processes of cell injury in the
spinal cord trauma, and (iii). the
dynorphin antiserum has potential therapeutic value for the treatment of
spinal cord injuries.