Pleasure Noms: Natural Pain Killer

Oct 15, 2009 • News, Research

Chocolate can relieve pain. Surprise, surprise.

A study, published in the Journal of Neuroscience by authors Peggy Mason, Ph.D., professor of neurobiology, and Hayley Foo, Ph.D., research associate professor of neurobiology at the University of Chicago, demonstrated the effect of chocolate, and apparently water also, in experiments conducted on rats.

If you can’t put your PETA-supporting selves on the shelf for a sec, skip this next part.

The rats were given a chocolate chip, sugar water, or water. As they consumed these items, a light bulb beneath the cage was turned on, creating a source of heat that generally made the rat lift its paw. When consuming chocolate or water, however, the rats were much slower to respond to the heat than they were otherwise. This is interesting because to date, it was believed that sugar was the cause of lowered sensitivity to pain.

Mason and Foo repeated the heat test and gave the rats were quinine, a bitter drink. In this instance, the rats reacted to heat as quickly as usual, which suggests that non-pleasurable food or drink fails to trigger pain relief.

A part of the brainstem called the raphe mangus, which is responsible for blunting pain during sleep, is thought to be at work during the consumption of pleasurable foods. The theory goes that animals need to focus on feeding to ensure survival, so when they encounter something pleasurable, the raphe mangus kicks in, enabling them to filter out distractions, such as heat and pain. The same part of the brainstem would not come into play if the food or liquid being ingested was not pleasant–possibly recognizing it as potentially toxic.

So, two things: chocolate is not quite Advil. And we don’t necessarily need sugar.

Thumbnail photo by distopiandreamgirl. Information via ScienceDaily.