A1 Refereed original research article in a scientific journal
Regulation of ion transport across lamprey (Lampetra fluviatilis) erythrocyte membrane by oxygen tension
Authors: Virkki LV, Salama A, Nikinmaa M
Publisher: COMPANY OF BIOLOGISTS LTD
Publication year: 1998
Journal:: Journal of Experimental Biology
Journal name in source: JOURNAL OF EXPERIMENTAL BIOLOGY
Journal acronym: J EXP BIOL
Volume: 201
Issue: 12
First page : 1927
Last page: 1937
Number of pages: 11
ISSN: 0022-0949
Abstract
We have measured the effects of oxygen tension on the transport of Na+, K+ and Cl- across the erythrocyte membrane of the lamprey Lampetra fluviatilis, The transport of each ion was affected by the oxygen tension of the medium. Hypoxic conditions (P-O2 2 kPa) caused an increase in the acidification-induced influx of Na+ via Na+/H+ exchange, The influx of K+ was only slightly affected by the oxygenation of the medium. In contrast, the basal K+ efflux, measured using the radioactive isotope K-43, was markedly reduced by decreasing the oxygen tension of the medium, whereas the K+ flux in hypotonic medium was not affected. Only minor effects of hypoxic conditions on the influx of Cl- were observed in either isotonic or hypotonic conditions (there was a tendency for the isotonic influx to increase) or on the efflux in isotonic conditions. However, deoxygenation caused a marked reduction in the Cl- efflux in hypotonic conditions. The results show that oxygen tension has a marked effect on the pH and volume regulatory transport pathways of lamprey erythrocytes. For K+ and Cl-, the regulation appears to be asymmetric, i.e. influx and efflux are affected differently.
We have measured the effects of oxygen tension on the transport of Na+, K+ and Cl- across the erythrocyte membrane of the lamprey Lampetra fluviatilis, The transport of each ion was affected by the oxygen tension of the medium. Hypoxic conditions (P-O2 2 kPa) caused an increase in the acidification-induced influx of Na+ via Na+/H+ exchange, The influx of K+ was only slightly affected by the oxygenation of the medium. In contrast, the basal K+ efflux, measured using the radioactive isotope K-43, was markedly reduced by decreasing the oxygen tension of the medium, whereas the K+ flux in hypotonic medium was not affected. Only minor effects of hypoxic conditions on the influx of Cl- were observed in either isotonic or hypotonic conditions (there was a tendency for the isotonic influx to increase) or on the efflux in isotonic conditions. However, deoxygenation caused a marked reduction in the Cl- efflux in hypotonic conditions. The results show that oxygen tension has a marked effect on the pH and volume regulatory transport pathways of lamprey erythrocytes. For K+ and Cl-, the regulation appears to be asymmetric, i.e. influx and efflux are affected differently.
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