J Exp Biol 2021 Mar 26. Epub 2021 Mar 26.
Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark.
The ability of crocodilian haemoglobins to bind HCO has been appreciated for more than half a century, but the functional implication of this is exceptional mechanism has not previously been assessed Therefore, the goal of the present study was to address the hypothesis that CO primarily binds to Hb, rather than being accumulated in plasma as in other vertebrates, during diving in caimans. Here, we demonstrate that CO primarily accumulates within the erythrocyte during diving and that most of the accumulated CO is bound to haemoglobin. Furthermore, we show that this HCO-binding is tightly associated with the progressive blood deoxygenation during diving, therefore, crocodilians differ from the classic vertebrate pattern, where HCO accumulates in the plasma upon excretion from the erythrocytes by the Cl-HCO-exchanger. Read More