Ampakines are a class of drugs that have been shown to reverse the adverse effects of cognitive disorders in rats. A new study indicates that they might also help rats with aging, but still healthy, brains. Could the future belong to these kinds of anti-aging drugs?
In the brain, the gaps between neurons are usually bridged by dendrites. These little branches help signals get from one neuron to another. In the young, dendrites are numerous and long. As people age, those dendrites retract, pulling back and reducing in number. But this process may no longer be inevitable, according to the results of an experiment conducted by researchers at the University of California, Irvine (UCI), and published in The Journal of Neuroscience.
Two groups of rats, 10 months old and approaching middle age in rat-years, were placed in a cage. They were given plenty of space, stimuli, and opportunities to exercise. Half of the rats were given ampakine. The others were given a placebo. The two groups enjoyed a happy life of new environments and gentle behavioral tests for 13 months, at which point it was time to examine their brains.
The UCI scientists found that while the brains of the placebo-treated rats were noticeably different from those of the young rats, the brains of the ampakine-treated rats were not. The dendrites were as long and numerous as those of young rats. What’s more, the dendrites of the ampakine-treated rats had more of the small projections, called dendritic spines, which neurons use to pick up and send out signals, than those of the young rats.
This was not just a physiological change. The ampakine-treated rats spent less time exploring new areas than the placebo-treated rats, which the researchers attribute to the ampakine-treated rats having better memories and better strategies when it came to exploring. They were better able to adjust to new environments.
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The UCI scientists believe that ampakine may work in humans as well. “The ampakine we used causes neurons to increase the production of the brain’s primary growth factor (Brain Derived Neurotrophic Factor: BDNF),” study co-author Gary Lynch told Gizmodo. “Human brain makes BDNF and there’s evidence that it’s functionally important.”
As with anything brain-related, early results don’t always bear out, as the study authors themselves stress. This study used only male rats. The researchers also don’t know how many days of treatment it takes to produce significant results, and whether they can get the same results with elderly rats that they do with middle-aged ones. And we don’t know for sure whether what works on rats will work on humans.
If it does, the implications are a little unnerving. These rats weren’t sick. They were just getting older. Ampakines are currently being considered as treatment for diseases like Alzheimer’s, but this would mean they could be a treatment for garden-variety aging. “What happens then?” said Lynch. “Aged people with all of the advantages of accumulated experience suddenly have brains that work as well as young adults? The personal and societal impact of all of this is hard to imagine.”
Ampakine as an anti-brain-aging drug would mean everyone in the future would be on ampakine. Perhaps the future belongs to whoever can make, or afford, the best anti-aging drugs. Medical progress has given billions of people better lives and has the potential to improve the lives of billions more. At the same time, this is a result that could make a whole new world—in more ways than one.
[The Journal for Neuroscience]
Image: Jason Snyder