Potassium transport in lamprey lampetra fluviatilis erythrocytes evidence for potassium channels
Gusev, G.P.; Sherstobitov, A.O.; Skulskii, I.A.
Comparative Biochemistry and Physiology A 101(3): 569-572
1992
ISSN/ISBN: 1095-6433 Accession: 007673254
Unidirectional K+ (86Rb) influx in lamprey red blood cells was studied under different conditions. The influx of 86Rb was markedly inhibited by 1 mM Ba2+ when cells were incubated in saline containing 4 mM K+. In K+-free media, the influx rate constant of 86Rb was lower, and 1 mM Ba2+ had no blocking effect. Treatment of the red cells with 0.1 mM ouabain in the absence of external K+ resulted in the appearance of the component of 86Rb influx inhibited by 1 mM Ba2+, quinine, TEA or amiloride. Similar results were obtained in red cells incubated in Na+-free media MgCl2-sucrose. The results obtained provide evidence for the existence of K+ channels in the red cell membrane of the lamprey. Under physiological conditions (in the presence of 4 mM K+) the total rate constant for the 86Rb influx in erythrocytes was about 1.9/hr, including ouabain-sensitive (0.6/hr), Ba2+-sensitive (1.1/hr) and residual (0.2/hr) components.