Circulation of the spinal cord studied by autoradiography

Abstract

Difference in extent and de-gree of penetration of tracer amounts of radiophosphorus (P32) in the spinal cord in dogs and monkeys following ischemia for various periods of time were studied by autoradiography. Ischemia was produced by temporary occlusion of the descending aorta immediately distal to the origin of the subclavian artery. Ischemia of 25 minutes or longer allowed the p32 to pass the blood-spinal cord barrier, but less than 25 minutes did not alter the barrier sufficiently to allow significant penetration of P32. Radioactivity was most marked with longer periods of ischemia and was greatest in the lower segments, being less in ascending segments of the thoracic region. No increase in radioactivity was noted in the lower cervical segments. Although more radioactivity was found in gray matter as compared with white matter, no differences were observed between the areas supplied by the anterior or posterior spinal arteries. The significance of these data in relation to spinal cord circulation and blood-spinal cord barrier were discussed.