A1 Refereed original research article in a scientific journal
INHIBITION OF ADRENERGIC PROTON EXTRUSION IN RAINBOW-TROUT RED-CELLS BY NITRITE-INDUCED METHEMOGLOBINEMIA
Authors: NIKINMAA M, JENSEN FB
Publisher: SPRINGER VERLAG
Publication year: 1992
Journal: Journal of Comparative Physiology B
Journal name in source: JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY
Journal acronym: J COMP PHYSIOL B
Volume: 162
Issue: 5
First page : 424
Last page: 429
Number of pages: 6
ISSN: 0174-1578
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.