Ethanol and acetaldehyde levels in cerebrospinal fluid during ethanol oxidation in the rat

The in vivo concentrations of ethanol and acetaldehyde were measured in peripheral blood and cerebrospinal fluid (CSF) of rats during 4 h after oral administration of 3 g ethanol/kg body wt. During the first 120 min of the experiment the concentration of ethanol in CSF was significantly higher than in peripheral blood. The concentration of acetaldehyde in blood and CSF were the same at 30 min, but throughout the remainder of the experiment the concentration of acetaldehyde in CSF was significantly lower than in the peripheral blood. These results show that the concentrations of ethanol and acetaldehyde in the peripheral blood do not quantitatively reflect the ethanol and acetaldehyde levels in the brain and further support the existence of a mechanism limiting the entry of acetaldehyde into the brain.