The Omnivore's Dilemma: A Natural History of Four Meals

by Michael Pollan

Later it occurred to me that this mental state, which I quite liked, in many ways resembled the one induced by smoking marijuana: the way one’s senses feel especially acute and the mind seems to forget everything outside the scope of its present focus, including physical discomfort and the passing of time. One of the more interesting areas of research in the neurosciences today is the study of the brain’s “cannabinoid network,” a set of receptors in the nervous system that are activated by a group of unusual compounds called cannabinoids. One of these compounds is THC, the active ingredient in marijuana; another is anandamide, a recently discovered neurotransmitter manufactured in the brain (and named by its discoverer for the Sanskrit word for inner bliss). Whether made by the plant or the brain, cannabinoids have the effect of intensifying sensory experience, disabling short-term memory, and stimulating appetite. Scientists still aren’t certain what the evolutionary utility of such a system might be. Some researchers hypothesize that the cannabinoids, like the opiates, play a role in the brain’s pain relief and reward system; others that they help regulate appetite, or emotion.