On the seemingly diminished CO2-Bohr effect in hypoxic chemodenervated rabbits.

ABSTRACT

In hypoxic rabbits, different levels of Pco2 before and after carotid chemodenervation were applied in order to get information about the acid-base status and the position of the O2-Hb dissociation curve (ODC). A CO2-induced change in pH caused a smaller change in the half-saturation pressure (P50) than was to be expected from the CO2-Bohr effect alone. Considering both, the numerically different CO2- and fixed acid-Bohr factors as well as the corresponding respiratory or metabolic pH changes, a method is presented to calculate the position of the ODC with high accuracy. From these considerations it can be derived that the seemingly diminished CO2-Bohr effect in hypoxic rabbits in vivo, especially after chemodenervation , is due more or less to accumulation of lactid acid. This leads to an increasing error if only the CO2-Bohr factor and the actual pH change are taken into account.