Title: A Scientific Explanation of How Marijuana Causes the Munchies  | Science   | Smithsonian Magazine
Headings: A Scientific Explanation of How Marijuana Causes the Munchies
A Scientific Explanation of How Marijuana Causes the Munchies
THC appears to increase our sensitivity to scents and flavors by using naturally occurring neural networks to convince the brain that it’s starving
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Content: A new study published today in Nature Neuroscience brings us a bit closer to solving the mystery. A team of European neuroscientists led by Giovanni Marsicano of the University of Bordeaux has found that, in mice, THC fits into receptors in the brain's olfactory bulb, significantly increasing the animals' ability to smell food and leading them to eat more of it. A big part of the reason why you might eat more food after using marijuana, the research indicates, is simply that you can smell and taste it more acutely. This effect of THC has to do with the underlying reason why the chemical affects the human brain so potently in the first place. Likely produced by the marijuana plant as a self-defense against herbivores who might feel disorientated after eating the plant and avoid it in the future, THC fits into receptors that are part of the brain's natural endocannabinoid system, which helps to control emotions, memory, pain sensitivity and appetite. Our brains typically produce their own chemicals (called cannabinoids) that fit into these same receptors, so by mimicking their activity, THC can artificially alter the same factors in dramatic ways. The scientists began by exposing mice ( increasingly used in neuroscientific research because of the surprising amount of cognitive similarities they share with humans) to banana and almond oils as a test of sensitivity to scent. When they did so, the mice sniffed the oils extensively at first, then stopped showing interest in them, a well-known phenomenon called olfactory habituation. Mice that were dosed with THC, however, kept on sniffing, demonstrating an enhanced sensitivity to the scents. These THC-dosed mice also ate much more chow when given the chance, showing an increased appetite.