Freshwater Crayfish 7(1): 203-210 (1979)
Physiological responses of the crayfish Pacifastacus leniusculus to environmental hyperoxia: Acid-base and ionoregulation
Increased ambient O2 tension (hyperoxia, P02 = 500 Torr) was employed to generate a respiratory acidosis in the hemolymph of P. leniusculus in order to analyse subsequent mechanisms of acid-base compensation. Crayfish were able to completely restore circulating pH within 24 h by accumulating metabolic bicarbonate (HC03) at fixed CO2 tension. During this time a net branchial excretion of acidic equivalents was measured, which was correlated with a more negative Cl- balance. Changes in net Na+ movement were due to changes in the exchange diffusion component (Na+/Na+) and were not associated with H+ or NH4 exchange. There was however a good correlation between Cl- outflux and Hco3 uptake suggesting that HCO3- is accumulated in the hemolymph by reversal of the branchial Cl-/HCO3- exchanger. Collection of urine revealed that the antennal gland was also involved in acid-base regulation duririg hyperoxia since titratable acidity and ammonia excretion increased. Clearance ratio analysis failed to reveal any changes in postfiltrational electrolyte reprocessing mechanisms.
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How to Cite
Whealtly MG. (1979). Physiological responses of the crayfish Pacifastacus leniusculus to environmental hyperoxia: Acid-base and ionoregulation. Freshwater Crayfish 7(1):203-210. doi: .