Forgetful? Study finds new drug that could help

Brett Smith for redOrbit.com – Your Universe Online

Studies have shown that forgetfulness as we get older can be seen in the form of neurons in our brains beginning to fray and disappear.

Now, a new study published in Proceedings of the National Academy of Sciences has found that a drug used to treat Lou Gehrig’s disease (ALS) called riluzole can prevent these changes in lab rats, and could lead to effective treatments in humans.

“By examining the neurological changes that occurred after riluzole treatment, we discovered one way in which the brain’s ability to reorganize itself — its neuroplasticity — can be marshaled to protect it against some of the deterioration that can accompany old age, at least in rodents,” said  study author Bruce McEwen, head of the neuroendocrinology lab at The Rockefeller University in Manhattan.

The study team said they explicitly chose to study riluzole as a potential treatment for age-related cognitive decline because of its role in treating ALS, also a cognitive disorder. The scientists started by providing riluzole to rats as soon as they reached 10 months old, considered middle age when their cognitive slow-down normally begins.

After 17 weeks, the scientists screened the rats’ spatial memory, the kind of memory often studied in animals. The research team saw that the treated rats performed better on the tests than an untreated control group, and almost to the level of young rats. For example, when dropped in a maze they had already been around, the treated rats acknowledged the addition of an unfamiliar arm and spent more time examining it.

When the team examined the brains of the treatment group, they discovered telling shifts inside the hippocampus, a brain region linked to memory and emotion. In particular, the researchers saw in increased clustering of thin neural spines, when compared to younger rats and the control group, which exhibited the least clustering.

“We have found that in many cases, aging involves synaptic changes that decrease synaptic strength, the plasticity of synapses, or both,” said John Morrison, dean of basic sciences and the Graduate School of Biomedical Sciences at Mount Sinai. “The fact that riluzole increased the clustering of only the thin, most plastic spines, suggests that its enhancement of memory results from both an increase in synaptic strength and synaptic plasticity, which might explain its therapeutic effectiveness.”

The study team theorized that aging brain may compensate from neural decline by increasing clustering and riluzole appears to boost this mechanism.

“In our study, this phenomenon of clustering proved to be the core underlying mechanism that prevented age-related cognitive decline,” said study author Ana Pereira, an instructor in clinical investigation at Rockefeller. “By compensating the deleterious changes in glutamate levels with aging and Alzheimer’s disease and promoting important neuroplastic changes in the brain, such as clustering of spines, riluzole may prevent cognitive decline.”

In addition to investigating riluzole with respect to age-related cognitive decline, Pereira is also currently looking to see if the drug can be used to treat mild forms of Alzheimer’s disease.

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