Time course of red blood cell intracellular pH recovery following short-circuiting in relation to venous transit times in rainbow trout,Oncorhynchus mykiss

• DOI: 10.1152/ajpregu.00062.2018
• Publication Date: 2018-04-11T18:26:43Z
• Authors: Till S. Harter; Alexandra G. May; William J. Feders...; Claudiu T. Supuran; Colin J. Brauner
• Keywords: Intracellular pH; Oxygen transport

Accumulating evidence is highlighting the importance of a system enhanced hemoglobin-oxygen (Hb-O2) unloading for cardiovascular O2 transport in teleosts. Adrenergically stimulated sodium-proton exchangers (β-NHE) create H+ gradients across red blood cell (RBC) membrane that are short-circuited presence plasma-accessible carbonic anhydrase (paCA) at tissues; result large arterial-venous pH shift greatly enhances from pH-sensitive Hb. However, RBC intracellular (pHi) must recover during venous transit (31-90 s) to enable loading gills. The halftimes ( t1/2) and magnitudes β-adrenergic stimulation, short-circuiting with paCA recovery pHi, were assessed vitro, on rainbow trout whole blood, using changes closed-system partial pressure as sensitive indicator pHi. In addition, rate pHi was continuous-flow apparatus more closely mimics through circulation. Results indicate that: 1) t1/2 β-NHE likely within residence time capillaries, 2) 17 s transit, 3) after short-circuiting, RBCs reestablish initial gradient can potentially undergo repeated cycles recovery. Thus, teleosts have evolved Hb tissues, while protecting gills; resulting increase per unit flow may tremendous athletic ability salmonids.