Regulation of ion transport across lamprey (Lampetra fluviatilis) erythrocyte membrane by oxygen tension

: Virkki LV, Salama A, Nikinmaa M

Publisher: COMPANY OF BIOLOGISTS LTD

: 1998

: Journal of Experimental Biology

: JOURNAL OF EXPERIMENTAL BIOLOGY

: J EXP BIOL

: 201

: 12

: 1927

: 1937

: 11

: 0022-0949

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.