The interrelation between brain PO2 and NADH oxidation-reduction state in the gerbil

Abstract

The present investigation was aimed at studying the interrelation between hemodynamic, metabolic and oxygen tension in the brain of the gerbil exposed to various physiological and pathological conditions in the awake and anesthetized states. The hemodynamic and metabolic activities were evaluated by the DC fluorometer/reflectometer and were correlated to the pO2 values obtained by a surface electrode. When the awake brain was exposed to spreading depression (SD), a typical oxidation cycle of the NADH was recorded concomitant with a decrease cycle of the pO2. Under anesthetic effect the same dip in pO2 response was found but the NADH showed a "reduction cycle." The pO2 values were in a very good correlation with the changes in the reflectance trace, namely, the pO2 was a good indicator of the vasoconstriction-vasodilatation responses under various conditions. The same model was used under hypoxic and ischemic conditions, as well as under the effects of anesthetics.