Fish red blood cell carbon dioxide transport in vitro: A comparative study

摘要: Abstract Red blood cell (rbc) carbon dioxide transport was examined in vitro three teleosts (Oncorhynchus mykiss, Anguilla anguilla, Scophthalmus maximus) and an elasmobranch (Scyliorhinus canicula) using a radioisotopic assay that measures the net conversion of plasma HCO3− to CO2. The experiments were designed compare intrinsic rates rbc CO2 excretion impact haemoglobin oxygenation/deoxygenation among species. Under conditions simulating vivo levels natural haematocrits, rate whole varied between 14.0 μmol ml−1 h−1 (S. 17.6 (O. mykiss). separated significantly greater dogfish, S. canicula. contribution overall low dogfish (46 ± 6%) compared (trout, 71 4%; turbot, 64 5%; eel, 55 3%). To eliminate naturally occurring differences haematocrit [HCO3−] as inter-specific variables, determined had been resuspended constant (5 mmol−1) (20%) appropriate teleost Ringer solutions. such normalized conditions, higher turbot (22.4 1.3 h−1) comparison other species (16.4–18.4 thus revealed turbot. study Bohr protons, assessed subjected rapid oxygenation during initial phase 3 min period. Rapid enhanced but not elasmobranch. extent increase provided by linear function Haldane effect, quantified each from dissociation (combining) curves. steady-state deoxygenated exhibited than oxygenated As consequence intracellular pH increased deoxygenation unaltered results, extrapolation, suggest are influenced magnitude effect gill transit addition at which converts