The researchers have discovered how this mechanism is initiated in the endocannabinoid system in mice. The system allows communication between receptors in the brain and those involved in sensations such as euphoria, anxiety or even pain, that are also sensitive to cannabinoid substances, such as cannabis.
The research, led by Giovanni Marsicano, a INSERM research director at NeuroCentre Magendie, is published in Nature Neuroscience.
"The researchers discovered that the CB1 cannabinoid receptors control a circuit that connects the olfactory bulb (the region in the nervous system that initially handles olfactory information, located above the nose) to the olfactory cortex (higher structures of the brain). When the sensation of hunger is felt, it triggers the activity of the cannabinoid receptors, which in turn activate the olfactory circuit, which then becomes more responsive," according to a statement announcing the results.
This biological mechanism makes humans more sensitive to smell during hunger, explaining one of the drivers behind human attraction to food while they are hungry.
"The researchers expect that the circuit involved in the olfactory system is altered in obese or anorexic patients, and that sensitivity to smell may be more or less strong compared to normal. Elucidation of the biological mechanism will allow better management of these types of pathologies," concluded the statement.