A1 Refereed original research article in a scientific journal

INHIBITION OF ADRENERGIC PROTON EXTRUSION IN RAINBOW-TROUT RED-CELLS BY NITRITE-INDUCED METHEMOGLOBINEMIA




AuthorsNIKINMAA M, JENSEN FB

PublisherSPRINGER VERLAG

Publication year1992

JournalJournal of Comparative Physiology B

Journal name in sourceJOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY

Journal acronymJ COMP PHYSIOL B

Volume162

Issue5

First page 424

Last page429

Number of pages6

ISSN0174-1578


Abstract

The effects of nitrite-induced methaemoglobinaemia on adrenergic proton extrusion from rainbow trout red blood cells were studied using the pH-stat method. In control conditions adrenergic proton extrusion was completely inhibited by amiloride and was greater in deoxygenated than in oxygenated erythrocytes. Nitrite-induced methaemoglobinaemia was associated with a pronounced reduction in the catecholamine-stimulated proton efflux from both deoxygenated and oxygenated erythrocytes. In deoxygenated erythrocytes the initial proton efflux upon catecholamine stimulation decreased by 60-70%, while the percentage of methaemoglobin in the red cells increased from the control level of 1-3% to 20%. In oxygenated erythrocytes the decrease was 30% at the same methaemoglobin percentage range. It is suggested that the pronounced influence of nitrite-induced methaemoglobinaemia on adrenergic proton efflux results from an inhibition of the red cell sodium/proton exchanger by the R-like haemoglobin conformations.




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