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.

The effects of acute administration of the hydroalcoholic extract of rosemary (Rosmarinus officinalis L. ) (Lamiaceae) in animal models of memory

Rosmarinus officinalis (Rosemary) demonstrates antioxidant, antidepressant, diuretic, antinociceptive and antiulcerogenic activities. The present study was designed to examine the effects of the hydroalcoholic extract of R. officinalis on the memory of male mice. The behavioral tasks employed were social recognition (SR), the Morris water maze (MWM) and an inhibitory avoidance task (IA). The treatment with 150 and 300 mg/kg of R. officinalis improved the acquisition phase of learning of a new social memory in the SR task because a decrease was observed in the duration of social investigation. In the Morris water maze, no significant effect was observed on spatial memory when the groups were compared for the time spent in the correct quadrant. In the inhibitory avoidance task, the decrease in the step-down latencies in the test session indicate that 150 mg/kg of R. officinalis improved long-term memory when administered in the consolidation phase of learning. In conclusion, the present study showed that, the hydroalcoholic extract of R. officinalis at 150 and 300 mg/kg modulated the short- and long-term memories of mice, in a social recognition and inhibitory avoidance task, respectively. This modulator effect was shown to improve learning and memory processes.

Rosmarinus officinalis L. (Alecrim) possui atividade antioxidante, antidepressiva, diurética, antinociceptiva e antiulcerogênica. O presente estudo foi delineado para investigar o efeito do extrato hidroalcoólico de R. officinallis na memória de camundongos machos. Os modelos comportamentais utilizados foram a tarefa de reconhecimento social (RS), labirinto aquático de Morris (MWM) e esquiva inibitória (EI). O tratamento com 150 e 300mg/kg de R. officinallis, mostrou ter efeito positivo na aquisição de uma nova memória social, na tarefa de reconhecimento social, mostrando redução significativa do tempo de investigação social. No labirinto aquático de Morris, não foi visto efeito significativo na memória espacial, ao comparar o tempo desprendido no quadrante correto entre os diferentes tratamentos. Na esquiva inibitória a latência de descida da plataforma, observada na sessão teste, sugere que o tratamento com a dose 150 mg/kg de R. officinallis tem um efeito positivo na memória de longo prazo, quando administrada na fase de consolidação. Conclui-se que o extrato de R. officinalis nas doses de 150 e 300 mg/kg foi capaz de modular as memórias de curto e longo prazo dos roedores nas tarefas de reconhecimento social e esquiva inibitoria, respectivamente, e esse efeito modulatório melhorou os processos de aprendizado e memória.