title: Buffering characteristics of eel blood at the extreme conditions in the swimbladder.
abstract: CO2 binding in whole blood and true plasma of the eel was estimated by measuring CO2 content and pH in blood aliquots equilibrated with various PCO2 values over a wide range expected to occur in the swimbladder. Bicarbonate concentration, [HCO3-], was calculated using the CO2 solubility coefficient, which was measured to average 50 mumols.L-1.Torr-1 (20 degrees C). Buffer lines of non-bicarbonate buffers were obtained in plots of [HCO3-] against pH, and non-bicarbonate buffer values, beta NB, were obtained by curve fitting. In the pH range 6.6-8.2, the buffer line for oxygenated whole blood was sigmoid, while that for deoxygenated blood increased its slope monotonously with increasing pH. The beta NB for oxygenated blood displayed a maximum of about 8.6 mmol.L-1.pH-1 at pH = 7.4 and dropped down to below 1 mmol.L-1.pH-1 at higher and lower pH. Similar shapes of the buffer lines were obtained in true plasma; the [HCO3-] levels and beta NB values were, however, somewhat higher than in whole blood. These data are useful to assess the back-diffusion of CO2 and HCO3- in the rete mirabile of the fish swimbladder and to estimate the effects CO2 back-diffusion exerts on the counter-current enhancement of O2 in the rete.
authors.affiliation: Institut für Physiologie, Ruhr-Universität Bochum, F.R.G.
authors.forename: B
authors.initials: B
authors.lastname: Pelster
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: P
authors.initials: P
authors.lastname: Scheid
mesh_terms: D000400:Air Sacs / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002021:Buffers; D002245:Carbon Dioxide / Q000097:blood; D004524:Eels / Q000097:blood*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure
chemical_list: D002021:Buffers; D002245:Carbon Dioxide; D010100:Oxygen