Accession Number : ADA293327

Title :   Membrane Transport: A Cellular Probe of Heat Stroke.

Descriptive Note : Midterm rept.,

Corporate Author : GEORGIA UNIV RESEARCH FOUNDATION INC ATHENS

Personal Author(s) : Willis, John S.

PDF Url : ADA293327

Report Date : 02 FEB 1995

Pagination or Media Count : 37

Abstract : Red blood cells of guinea pig were used to explore the effects of temperatures above 37 deg C on membrane permeability to Na+ and K+ as part of an effort to evaluate the Energy Depletion Hypothesis of heat stroke. Cell Na+ and K+ does not change at 41 deg C and 45 deg C for up to 2 hours of incubation in simple saline medium. Na-K pump activity measured as ouabain-sensitive K+ influx increases with warming, as do Na+ influx and K influx. The rise in the pump activity matches the rise in Na+ influx quantitatively, accounting for the lack of change in Na+ cell. The rise in Na+ influx is in the face of a decrease in activity of Na-H exchange transport capacity. The rise in K+ influx consists largely of activation of a single, carrier-mediated path, K-C1 cotransport and corresponds to an apparent activation of this path in the reverse direction (K+ efflux), leading to dumping of K+ at elevated temperature. Na-K-C1, a third passive carrier pathway, shows a temperature optimum between 30 deg C and 37 deg C. A new hypothesis proposes that these diverse responses to temperature change contribute to the maintenance of ion balance.

Descriptors :   *TEMPERATURE, *PASSIVE SYSTEMS, *MEMBRANES, *BLOOD CELLS, *HEAT STROKE, MAINTENANCE, DEPLETION, IONS, PROBES, ACTIVATION, PERMEABILITY, HIGH TEMPERATURE, ENERGY, RESPONSE, REVERSIBLE, HEATING, TRANSPORT, BALANCE, INCUBATION, HYPOTHESES, SALINITY, PUMPS, ERYTHROCYTES, GUINEA PIGS.

Subject Categories : Medicine and Medical Research
      Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE