(1972). We observed the latency to seizure onset, the tonic-clonic seizure time, the total seizure time, the number of seizures and how many seizures reached the fifth stage HSP inhibitor on Racine’s scale (tonic-clonic seizures). Following the seizure tests, all animals, with or without PTZ treatment, were killed by decapitation. The hippocampus, cerebellum and cerebral cortex

were isolated and stored at −80 °C. Prior to each assay, the tissues were homogenized in phosphate buffered saline (pH 7.4) using a ground-glass-type Potter–Elvehjem homogenizer and were centrifuged for five minutes. The supernatant was used in all assays. All processes were carried out under cold conditions. To evaluate a possible neuroprotective effect of the juices, we measured the lipid and protein oxidative damage, the nitric oxide content and the enzymatic (superoxide dismutase and catalase) and non-enzymatic (sulfhydryl protein) antioxidant defenses.

We used the formation of thiobarbituric acid-reactive species (TBARS) during an acid-heating reaction as an index of lipid peroxidation, as previously described by Wills (1996). The results were expressed as nmol of malondialdehyde (MDA)/mg protein. The oxidative damage to proteins was assessed by the formation of carbonyl groups based on the reaction with dinitrophenylhydrazine, as previously described by Levine et al. (1990). The results

were expressed CP 673451 as nmol/mg of protein. Nitric oxide production below was determined based on the Griess reaction (Green et al., 1981). Nitrite concentration was determined from a standard nitrite curve generated using sodium nitroprusside. The results were expressed as mg/mL of sodium nitroprusside/mg protein. Superoxide dismutase (SOD) activity was assayed by measuring the inhibition of adrenaline auto-oxidation, as previously described (Bannister and Calabarese, 1987), and the results were expressed as U SOD (units of enzyme activity)/mg of protein. One unit was defined as the amount of enzyme that inhibits the rate of adrenochrome formation in 50%. Catalase (CAT) activity was assayed by measuring the rate of decrease in hydrogen peroxide (H2O2) absorbance at 240 nm, as previously described (Aebi, 1984), and the results were expressed as mmol H2O2/min/ mg of protein. The protein sulfhydryl content was evaluated by the 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) method (Aksenov and Markesbery, 2001), and the results are expressed as nmol DTNB/mg of protein. Protein concentration was measured by the Bradford method Bradford (1976) using bovine serum albumin as a standard. The total phenolic content of the organic and conventional grape juices were measured using the modification of the Folin–Ciocalteau colorimetric method, as described by Singleton et al. (1999).