The involvement of increased brain tissue CO
2 tension in acetazolamide-induced brain acidosis was investigated by comparing the brain pH response to acetazolamide with that to hypercapnia. CO
2 and pH sensors were placed bilaterally into cerebral white matter to 15 mm depth in cats. Group I cats (n = 9) breathed spontaneously, and in situ brain tissue P
CO2 and pH (Pb
CO2 and pHb) were measured after intravenous acetazolamide administration (20 mg/kg). Group 2 cats (n = 9) were paralyzed and ventilated mechanically, and the changes of pHb were investigated by adjusting the ventilation to maintain the same Pbco
2 values as in the acetazolamide-treated group. Pbco
2 changes were not significantly different between the two groups. However, pHb responses were quite different: the fall in pHb was progressive in Group 1 but transient in Group 2. Brain acidosis after acetazolamide administration is not due to the rise in brain tissue CO
2 tension.
View full abstract