Temperature acclimation of respiratory function in the salamander Taricha granulosa

The effect of acute and chronic temperature change on oxygen uptake (VO2) and the respiratory properties of blood was determined in the newt, Taricha granulosa. Acclimation to 20-24 degrees C for 4 weeks caused a significant increase in hemoglobin concentration (6.5-9.5 g/dl) and O2 capacity of blood but no change in oxygen affinity compared with animals acclimated to 4-6 degrees C. Cold acclimated animals had a reverse Bohr effect compared with warm acclimated animals (dlogP 50/dpH = +0.13 and -0.12, respectively) but the present data offer no mechanism. There was no difference between the two acclimation groups with respect to temperature sensitivity of O2 binding, cooperativity of binding, buffer capacity, red cell organic phosphate concentration, or red cell dimensions. There was no evidence for thermal acclimation of VO2. Over the seasonal range of water temperature experienced by this species (5-25 degrees C), the major adaptation to the ca. 4 fold increase in VO2 is a 49% increase in blood O2 capacity.