Vitamin D₃ mediates spatial memory improvement through nitric oxide mechanism in demyelinated hippocampus of rat

Abstract

Studies have revealed beneficial role of vitamin D₃ in neuro-cognitive function. There is also supporting evidence on the involvement of nitric oxide (NO) in the neuro-protective action. However, its over production could contribute to brain disorders. In this study, demyelination was induced by ethidium bromide (EB) injection into the right side of the hippocampus area of male rats. Vitamin D₃ was administered to rats for 7 and 28 days prior to behavioral experiments using Morris water maze (MWM). Travelled distance, time spent to reach the platform, and time spent in target zone, were considered for learning and spatial memory evaluation. Nitrite oxide (NO2^-) concentration was measured as an indicator for nitric oxide production. The time spent to reach the platform and the travelled distance were decreased significantly by 28 days of vitamin D₃ administration (compared to 7 days experiment). Time spent in target quadrant was significantly lowered by administered vitamin on day 28. Therefore, considering a number of studies that have shown the effect of vitamin D₃ on cognition, these findings could support their potential effect. Besides, nitric oxide concentration significantly differed in 28 days of vitamin D₃ treated group compared with the groups treated with EB or 7 days of vitamin D₃.

Keywords:
Vitamin D₃; Nitric oxide concentration; Spatial memory; Ethidium bromide; Morris water maze