In today’s Economist, an article on anaesthesia states that the neurotransmitter glutamate plays an important roll in our ability to sense pain. A drug called ketamine “blocks the activity of glutamate by occupying the receptor molecules in the brain to which it would otherwise bind. That stops pain signals getting through.”

What does this have to do with sushi? Glutamate (also glutamic acid) plays a role in my book The Zen of Fish, because it is the key flavor component of soy sauce (and a partner in the flavor of miso soup). I knew that glutamate was an important neurotransmitter, but hadn’t realized it was a key player in pain transmission.

Anyone paying attention will notice that a version of glutamate is also the key flavor component of monosodium glutamate, a.k.a. MSG. The story of how Japanese scientists (not Chinese) invented MSG by studying soy sauce and miso soup is a particularly interesting passage in The Zen of Fish.

So does this mean that after you eat your favorite take-out Chinese food, you’re going to be more sensitive to pain? Certainly many people have complained of an unpleasant “Chinese restaurant syndrome” after consuming food with MSG, but the scientific validity of this ailment is hotly debated. I wonder if MSG simply causes some people’s pain circuitry to buzz, due to an overabundance of neurotransmitters.

If you’re interested in this subject and are up for a trip to the library, check out an article in the food journal Gastronomica by Jordan Sand called “A Short History of MSG” (vol. 5, no. 4). I read it while researching The Zen of Fish and found it utterly fascinating.