Compensation for injury potential by electrical stimulation after acute spinal cord injury in rat

Injury potential, a direct current potential difference between normal section and the site of injury, is a significant index of spinal cord injury. However, its importance has been ignored in the studies of spinal cord electrophysiology and electrical stimulation (ES). In this paper, compensation for injury potential is used as a criterion to adjust the intensity of stimulation. Injury potential is modulated to slightly larger than 0 mV for 15, 30 and 45 minutes immediately after injury by placing the anodes at the site of injury and the cathodes at the rostral and caudal section. Injury potentials of all rats were recorded for statistical analysis. Results show that the injury potentials acquired after ES are higher than those measured from rats without stimulation and much lower than the initial amplitude. It is also observed that the stimulating voltage to keep injury potential be 0 remain the same. This phenomenon suggests that repair of membrane might occur during the period of stimulation. It is also suggested that a constant voltage stimulation can be applied to compensate for injury potential.