An article appearing yesterday in PloS Biology reports that an Ampakine known as CX717 can alleviate cognitive impairment due to sleep deprivation. The study was done in monkeys although the company that produced the drug - Cortex Pharmaceuticals, has announced in a press release that there is evidence that it works in humans as well.
The monkeys were first tested on a simple cognitive task (delayed-match-to-sample). They performed significantly better when administered CX717. After sleep deprivation of 30 to 36 hours, the same monkeys showed a markedly decrease in ability to perform the task. However, when given CX717 afterwards their performance improved dramatically, even exceeding normal levels.
The brains of the monkeys were imaged with a PET scan for glucose use during these tests. The researchers found that the medial temporal lobe (MTL) and dorsal prefrontal cortex (DPFC) showed enhanced activity during the task. With CX717, there was a slight increase in activity in these two regions and a greater increase of activity in the precuneate cortex. Sleep deprivation caused an increase in activity in MTL and precuneus but a decrease in the DPFC. With CX717, the brain activity in the sleep deprived animals approached normal vehicle levels.
Ampakines are positive modulators of the glutamate AMPA receptor. Glutamate is the main excitatory neurotransmitter in the brain. The AMPA receptor when activated produces a short (few ms) excitatory post-synaptic voltage pulse. Ampakines can make this pulse stronger and last longer. The interesting thing is that the addition of CX717 to the sleep deprived animal increased activity in some areas but decreased it in others. This goes to show you that jazzing up excitation in the brain does not necessarily lead to increased activity. Unfortunately, PET scans can only tell us about changes in glucose usage and not the actual neural activity.
It will only be a matter of time when these drugs hit the streets and college campuses. Students already take speed to stay up and Ritalin to enhance concentration. NMDA and CREB enhancers to boost memory will also soon be on the market. The CB1 blocker rimonobant will soon be approved as an obesity drug. Personally, I wouldn't go near any of this stuff. We have no idea what long term effects these drugs will have. The brain is probably pretty optimized so any enhancement will have some trade-off. I think I would like to know what that cost will be before I decide to mess with my brain.
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