[The blood flow in normal and injured spinal cord--experimental studies by the heat clearance method]

The heat clearance method was used to study the blood flow in normal and injured thoracic spinal cord in dogs. In normal spinal cord, inhalation of 5% CO2 and intravenous injection of papaverine increased the spinal cord blood flow. These effects are quite similar to those of the brain. By thoracic aortic throttling, spinal cord blood flow patterns have been differentiated to be of 3 types. These differences seem to depend on the anatomical variations of the spinal cord blood supply. In injured spinal cord, the responses to inhalation of CO2 and papaverine have been gradually decreased and lost by 2 hours after injury. The responses to thoracic aortic throttling have been also decreased and delayed after injury. From these experiments, the ischemic response to spinal cord injury seems to be mediated both by the loss of autoregulation and by the vasoconstriction.