Blood Gas Tensions and Acid-Base Regulation in the Salt-Water Crocodile, Crocodylus Porosus, at Rest and After Exhaustive Exercise

摘要: 1. Salt-water crocodiles, Crocodylus porosus Schneider, were catheterized and Po2, Pco2, pH lactate concentration ([lactate]) measured in arterial blood during rest after forced exhaustive activity at 30°C. 2. 2. Gas exchange ratio (R), calculated from Po2 decreased about 1.0 to 0.3 resting voluntary breath-holding indicated CO2 sequestration the body fluids. The mean value for R undisturbed animals was 0.6, which substantiates hypothesis that some excretion is extrapulmonary. 3. 3. In vitro buffer of true plasma −23.5±1.9 mmol HCO3-1−1 pH−1. vivo value, determined by short-term self titration with metabolic CO2, −12.2±4.7mmolHCO3-1−1 pH−1. 4. 4. Exhaustive 5 min laboratory resulted pronounced lactacidosis: approximately 7.43 7.11 while increased 1.2 20–30 mmoll−1. acidosis reduced respiratory compensation first hour recovery adjustments practically complete third hour. Greater (pH down 6.4) larger field-captured resolved over a longer period. 5. 5. During recovery, proton fluxes between other tissue uncoupled. 6. 6. virtual absence fixed-acid Bohr effect C. adaptive large individuals because it facilitates continued O2 uptake lung into may be acidified as much 1 unit result physical activity.