Homeostasis of Sodium and Potassium Ions in Erythrocytes of the Lamprey Lampetrafluviatilis:Effect of Ion Transport and Metabolic Blockers,and lonophores

摘要

After incubation of lamprey Lampetrafluviatilis erythrocytes in the standard medium for 90-120 min,intracellular Na~+ and K~+ content remained unchanged(28.7(+-)1.1 and 66.3 +1.5 mmol/1 cells,respectively,n = 33).The erythrocyte ion content also did not change after treatment of the cells with ion transport inhibitors,Ba~+ and amiloride.Addition of 0.1 mM ouabain to the incubation medium led to a decrease of K~+ content by 8.4(+-)1.2 and to an increase of Na~+ content by 2.4(+-)0.8 mmol/1/2 h.Similar reciprocal changes in the cellular ion composition were observed after treatment of the erythrocytes by oxidative metabolism inhibitors(rotenone and CCCP-carbonyl cyanide m-chlorophenyl-hydrazone).The metabolic blockers produced more significant ion composition changes in comparison with ouabain.An increase of intracellular Na~+ content under effect of CCCP was completely inhibited by amiloride.It can be suggested that inhibition of oxidative metabolism is accompanied by a cell acidification and Na~+/H~+ exchange activation.Erythrocyte acidification by a K~+/H~+ ionophore led to a rapid cellular Na+ accumulation,which indicates the presence of a Na~+/H~+ exchanger with high activity.The K~+ ionophore valinomycin produced a relatively small K~+ loss from the lamprey erythrocytes to indicate a low anion conductance of the cells.The data obtained indicate an important role of oxidative metabolism in the monovalent ion homeostasis in the lamprey red blood cells.