How cannabis increases appetite
The uncontrollable urge to eat after using cannabis appears to be driven by neurons in the brain that are normally involved in suppressing appetite, according to a new study by Yale School of Medicine researchers in the journal Nature. Lead author Tamas Horvath and his colleagues set out to monitor the brain circuitry that promotes eating by selectively manipulating the cellular pathway that mediates the action of THC on the brain, using transgenic mice.
“By observing how the appetite center of the brain responds to marijuana, we were able to see what drives the hunger brought about by cannabis and how that same mechanism that normally turns off feeding becomes a driver of eating,” said Horvath, director of the Yale Program in Cell Signaling and Neurobiology of Metabolism. “We were surprised to find that the neurons we thought were responsible for shutting down eating, were suddenly being activated and promoting hunger, even when you are full. It fools the brain’s central feeding system,” he said. A group of nerve cells called pro-opiomelanocortin (POMC) neurons are considered as key drivers of reducing eating when full. The activation of cannabinoid-1 receptors by THC promotes the activity of POMC cells.
Koch M, Varela L, Kim JG, Kim JD, Hernández-Nuño F, Simonds SE, Castorena CM, Vianna CR, Elmquist JK, Morozov YM, Rakic P, Bechmann I, Cowley MA, Szigeti-Buck K, Dietrich MO, Gao XB, Diano S, Horvath TL. Hypothalamic POMC neurons promote cannabinoid-induced feeding. Nature. 2015 Feb 18. [in press]