The investigation of sulfite intake dependent alterations in eeg and locomotor activity in preadolescent rats together with molecular mechanisms

Objective: Sodium metabisulfite, a food additive has been reported to possess toxic actions when consumed at amounts above safe level. Public health screenings have revealed that sulfite intake among children can reach up to 110 times of the acceptable daily level. Considering the increase in the number of children diagnosed with ADHD, and our previous observations related to sulfite intake, the idea of the possibility of sulfite to contribute to ADHD development in children emerged, and the investigation of whether the abnormalities associated with ADHD ethiologytake place in sulfite neurotoxicity was targeted. Methods: Rat pups, 20-day old, were divided into K, S25 and S100 groups. S25 and S100 groups were daily given sodium metabisulfite at doses of 25mg/kg and 100mg/kg, respectively, and K group was administered tap water by gavage. Behavioral alterations were evaluated by open field and elevated plus maze tests. EEG From frontal and motor cortices were recorded bilaterally. Glutamate, glutamine, AKG levels, GDH, ALT activities and GDH, ALT mRNA levels were measured in the frontal lobe. Results: The total distanced moved, the number of squares entered and velocity were higher in S100 group compared to K group. The time spent in the open arm in the elevated plus maze was lower in S100 group in reference to K group.EEG Recordings revealed enhanced δ, θ, β1and δ, θ, β2 frequency bands for frontal and motor cortices, respectively, both in S25 and S100 groups. No difference was found for AKG levels; however, ALT and GDH activities were lower and higher in S100 group, respectively. Glutamine levels increased in both S25 and S100 groups compared to K group. Glutamate level was only higher in S100 group. Whereas ALT expression presented a decrease in S25 and S100 groups, there was no alteration in terms of GDH expression. Conclusion: Our findings pointed out that sulfite intake might contribute to ADHD development in childhood rat model. Thus, the effects of sulfite on neurodevelopmental processes and the screening of sulfite intake in our country are suggested. Key words: Sodium metabisulfite, ADHD, Glutamate regulation, EEG