Accession Number : AD0702745

Title :   RENAL HEMODYNAMIC RESPONSE OF UNANESTHETIZED DOGS TO NEGATIVE ACCELERATION,

Corporate Author : NAVAL AIR DEVELOPMENT CENTER JOHNSVILLE PA AEROSPACE MEDICAL RESEARCH DEPT

Personal Author(s) : Chimoskey,John E.

Report Date : 02 MAR 1970

Pagination or Media Count : 23

Abstract : Trained unanesthetized dogs were exposed to negative centrifugal accelerations up to -3Gz. Renal arterial pressure and inferior vena cava pressure at kidney level were measured through indwelling catheters. Renal blood flow velocity was measured by a Doppler flow meter. The flow signal was telemetered and the pressure signals were transferred by slip rings from the centrifuge. About 10 days after the sensing devices were implanted under pentobarbital anesthesia, the experiments began for which the dogs were unanesthetized. Renal blood flow velocity decreased in proportion to the magnitude of -Gz. The minimum flow velocity was significantly lower during -3Gz than it was during -1 and -2Gz. By the end of the 27 to 30 second periods of constant -Gz, flow velocity recovered significantly from the minimum values. The lowest mean arterial-venous pressure gradient, 129 plus or minus 7 (S.E.) mm Hg, recorded during -3Gz, did not differ significantly from the mean preacceleration value. Calculated intrarenal resistance to blood flow increased. Flow velocity reductions on a given day were frequently smaller after the first acceleration. (Author)

Descriptors :   (*KIDNEYS, BLOOD CIRCULATION), (*BLOOD CIRCULATION, ACCELERATION), BLOOD PRESSURE, DOGS, STRESS(PHYSIOLOGY), RESPONSE(BIOLOGY), ACCELERATION TOLERANCE, VELOCITY, ELECTROCARDIOGRAPHY

Subject Categories : Stress Physiology
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE