Chocolate ingredient improves memory in snails
Epicatechin, a flavonoid chemical found in dark chocolate, has been shown to have significant effects on the memory of the great pond snail.
By Tyler Irving
Posted November 2012
How good is a snail’s memory? It may depend on what it has eaten. A new study shows that a molecule found in dark chocolate can have positive effects on the long-term memory of these slow-moving mollusks.
Previous studies in rodents have suggested that flavonoids — plant metabolites often found in tea, wine and dark chocolate — are associated with improvements in learning and memory. However, the mechanism has been unclear: they might facilitate the growth of new cells and blood vessels in the brain, act as anti-oxidants preventing the death of existing neurons, or act independently. To find out, Ken Lukowiak, professor in the Hotchkiss Brain Institute at the University of Calgary, turned to a unique model organism: the great pond snail (Lymnaea stagnalis). Because the snails absorb drugs through their skin, have an open circulatory system and can be trained in only 30 minutes, the effects of growing or dying blood vessels and neurons on memory can be eliminated.
The team lowered the oxygen content of the water the snails live in by bubbling nitrogen through it. This caused the snails to open up their pneumostome (breathing tube) to get oxygen from the air. By gently tapping them with a stick, the researchers trained the snails to keep their tubes closed. Most snails remember this lesson for only about three hours, but in a paper published in the Journal of Experimental Biology, the team showed that snails exposed to 15 mg/L of the flavonoid (-)epicatechin through the water remembered the task even after 24 hours. “To get a 24-hour memory, you have to have altered gene activity, implying a significant change to the neuron,” says Lukowiak.
The team is now testing neurons isolated from snails to figure out what those biochemical changes might be. As for effects in humans, Lukowiak is circumspect. “As far as I know, no one has actually looked at this in humans, but if I had to bet money, I’d say it probably helps. If tea, wine or dark chocolate makes you happier and less stressed, your memory will probably improve as well.”
Photo credit: Ken Lukowiak
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