Accession Number : ADA020320


Title :   Physiologic Control of Spinal Cord Blood Flow,


Corporate Author : ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD


Personal Author(s) : Kobrine,A. I. ; Doyle,T. F.


Report Date : OCT 1975


Pagination or Media Count : 20


Abstract : The hydrogen clearance technique was used to measure spinal cord blood flow (SCBF) in the rhesus monkey to test the hypothesis of autoregulation in the spinal cord. Laminectomies were performed at the T9-T10 level, and 250-micrometers diameter platinum electrodes were placed through the intact dura, 2 mm into the spinal cord, midway between the midline and lateral borders. Flows were calculated from the desaturation curves of inhaled hydrogen. When the mean arterial pressure (MAP) was kept normal and the PaCO2 was varied by hyperventilation or changes in inspired CO2, SCBF remained normal with PaCO2 values of 10 to 50 mm Hg. SCBF increased as PaCO2 was raised from 50 to 90 mm Hg. Above a PaCo2 of 90 mm Hg, SCBF did not increase. When PaCO2 was kept constant and MAP was varied by norepinephrine infusion or bleeding, SCBF was constant and in the normal range when the MAP was between 50 and 135 mm Hg. Above 135 mm Hg MAP, the SCBF increased directly with MAP. Below 50 mm Hg, SCBF decreased directly with MAP. (Author)


Descriptors :   *BLOOD CIRCULATION, *SPINAL CORD, *ADAPTATION(PHYSIOLOGY), CONTROL, HYDROGEN, PHYSIOLOGICAL EFFECTS, CARBON DIOXIDE, PH FACTOR, CENTRAL NERVOUS SYSTEM, ARTERIES, RHESUS MONKEYS, BLOOD PRESSURE, PARTIAL PRESSURE, CEREBROVASCULAR SYSTEM, HYPERVENTILATION.


Subject Categories : MEDICINE AND MEDICAL RESEARCH


Distribution Statement : APPROVED FOR PUBLIC RELEASE