title: Acid-base status of fish at different temperatures.
abstract: In the water-breathing fishes, rising temperatures are accompanied by progressive reduction in pH, reductions in bicarbonate concentration, and slight rises in CO2 partial pressure. The pH-temperature slope of both intra- and extracellular compartments varies considerably, from -0.009 to -0.033/degrees C, with a rather consistent pattern of red muscle greater than white muscle greater than heart. Three different approaches to acid-base analysis, the imidazole-alphastat model, the strong-ion difference analysis, and the delta-bicarbonate approach, were applied to a set of data from the fresh-water channel catfish (Ictalurus punctatus). A principal difficulty encountered in using all three approaches was that assumptions were required regarding the chemical behavior of the intracellular buffers, but the delta-bicarbonate approach has the practical advantage of emphasizing parameters that can be measured directly. Closed-system models are not generally applicable to fish, and the interest for future work lies in deciphering the significance of tissue-to-tissue variations in pH regulation and in elucidating the mechanisms of the strong-ion transfers.
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D001639:Bicarbonates; D002021:Buffers; D005399:Fishes / Q000097:blood / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000378:metabolism; D007424:Intracellular Fluid / Q000502:physiology; D008954:Models, Biological; D010710:Phosphates; D013696:Temperature
chemical_list: D001639:Bicarbonates; D002021:Buffers; D007093:Imidazoles; D010710:Phosphates; C029899:imidazole