Sulfur dioxide derivatives attenuates consolidation of contextual fear memory in mice.

Post-traumatic stress disorder (PTSD) is characterized by an enhancement of traumatic memory. Intervention strategies based on the different stages of memory have been shown to be effective in the prevention and control of PTSD. The endogenous gaseous molecule, sulfur dioxide (SO2), has been reported to significantly exert neuromodulatory effects; however, its regulation of learning and memory remains unestablished. This study aimed to investigate the effects of exogenous SO2 derivatives administration on the formation, consolidation, reconsolidation, retention, and expression of contextual fear memory. Behavioral results showed that both intraperitoneal injection (50 mg/kg, ip) and hippocampal infusion (5 μg/side) of SO2 derivatives (a mixture of sodium sulfite and sodium bisulfite, Na2SO3/NaHSO3, 3:1 M/M) significantly impaired consolidation but had no effect on reconsolidation and retention of contextual fear memory. These findings suggest that the attenuating effects of SO2 on the consolidation of fear memory involves, at least partially, the region of the hippocampus. The findings of this study provide direct evidence for the development of new strategies for PTSD prevention and treatment involving the use of gaseous SO2.