Iodoantipyrine and Rb⁸⁶ Cl uptake by brain, cord, and sciatic nerve in the rat

¹ Department of Physiology, Ohio State University, Columbus, Ohio, and 6570th Aerospace Medical Research Laboratories, Wright-Patterson Air Force Base, Ohio

Rb⁸⁶ and Iodo¹³¹ antipyrine were injected together by vein in rats. The brain, spinal cord, and nerve contents of each label were measured 30 or 60 sec later. Iodoantipyrine values were used to calculate blood flow to these portions of the nervous system. The ratio of Rb⁸⁶ to iodoantipyrine uptake was used as an index of the efficacy of the hematoneural barrier. The barrier is most complete in the brain, less complete in the spinal cord, and absent in peripheral nerve. Blood flow values per gram are: brain .41 ml/g min; cord .28 ml/g min, and nerve .11 ml/g min. It is suggested that the blood-brain barrier is an anatomical entity rather than a functional one.