Complex effects of cannabinoids on feeding

Previous work has established a role for hypothalamic pro-opiomelanocortin (POMC) neurones in reducing feeding due to satiety, suggesting that signals promoting feeding may reduce POMC neuronal activity. Tamas Horvath and colleagues have tested this idea and find that, surprisingly, cannabinoid feeding signals enhance POMC neuronal activity. This paradoxical POMC neuronal activation is indispensable for appropriate promotion of feeding triggered by cannabinoid receptor 1 activation in the state of satiety. The authors conclude that the overall effect of cannabinoids on feeding may be driven by both pre- and post-synaptic effects — possibly independently from one another — and that it is their temporal synchrony that brings about the overall behavioural changes.