Nitric oxide plays a role in anxiety- and depression-like behaviors induced by sodium metabisulfite intake in rats.

This study was carried out to investigate the effects of sulfite toxicity anxiety- and depression-like behaviors and elucidate the involvement of nitric oxide (NO) in this interaction. One hundred male Wistar rats were divided into four groups. S25, S100, and S260 groups were given sulfite at doses of 25 mg/kg, 100 mg/kg, and 260 mg/kg, respectively, while the control (C) group received equal volumes of distilled water via gavage for 35 days. Fifteen rats from all groups were subjected to behavioral experiments. Five rats from each group were used for Long-Term Potentiation (LTP), and the other five rats were used for Long-Term Depression (LTD) recordings. The levels of nitrite/nitrate, neuronal nitric oxide synthase (nNOS), and inducible nitric oxide synthase (iNOS) were analyzed in the hippocampi. Behavioral experiments demonstrated that sulfite exposure may cause anxiety- and depression-like behaviors, especially at 100 mg/kg and 260 mg/kg doses. Moreover, sulfite exposure impaired LTP and facilitated LTD in the hippocampus. Besides, the levels of nitrite/nitrate, nNOS, and iNOS were significantly lower in the S100 and S260 groups compared to the C group. Overall, the results showed that sulfite toxicity in adults may induce anxiety- and depression-like behaviors. These findings suggest that sulfite-induced anxiety- and depression-like behaviors may be related to a reduction in NO production.