Detection of the lipid peroxidation product malonaldehyde in rat brain in vivo

The extracellular concentrations of the lipid peroxidation product malonaldehyde (MDA) and the antioxidants ascorbic and uric acid were measured in rat brain in vivo using microdialysis coupled to HPLC with ultra violet spectrophotometry. Treatment with kainic acid at pH 4.1 (50 nmol) caused a significant increase in the sampled concentration of MDA but no significant changes in the antioxidants. Treatment with the same dose of kainic acid at pH 7.2 did not cause a significant increase in MDA, although some changes were noted in the antioxidants. The paper demonstrates the ability to monitor changes of a lipid peroxidation breakdown product as a measure of oxidative stress in vivo. Furthermore, the data suggests that the toxic action of kainic acid in acute preparations may be due to the elevation of hydrogen ions.