Treatment with Simvastatin, one of the statin drugs widely used for lowering cholesterol in humans, significantly improved spatial memory - how to navigate a water maze - in mice genetically bred to have an Alzheimer's like disease.
Although
statin improved memory in both males and females, the results were more pronounced in males.
Dr. H. A. Morcos, chair of Pharmacology at the American University of Antigua, and colleagues at Florida A & M University presented the study April 30 at Experimental Biology 2007 in Washington, DC. His presentation is part of the scientific program of the American Society for Pharmacology and Experimental Therapeutics.
The study confirmed the Morcos laboratory's earlier findings of improved memory in this mouse model of Alzheimer's and discovered new information about the neurochemical basis of the beneficial effects. Various studies have found evidence of a strong relationship between memory deficits and high levels of cholesterol in the brain, suggesting that statin's effects on memory might be due to a reduction in cholesterol biosynthesis.
In this study, Dr. Morcos found that nNOS (neuronal nitric oxide synthase) levels were significantly higher in the hippocampus and cortex of statin treated groups as compared to similar mice that did not receive statin. Furthermore, the levels of nNOS proteins were statistically higher in the hippocampus of the statin treated animals than in the cortex. nNOS is responsible for the release of nitric oxide, a substance that causes dilation of the blood vessels in the brain, which eventually will increase blood flow and improve circulation to the memory region of the brain. These findings suggest that increases in brain nNos levels may play an important role in statin-induced improvement of spatial reference memory.