In the face of the growing obesity epidemic, much research has focused on the neuronal control of feeding behaviour. Agouti-related protein (AgRP) neurones express three proteins that have been implicated in changes in energy balance, but the studies linking AgRP neurones to feeding behaviour have produced mixed results.
To directly analyse the role of AgRP neurones, Bradford Lowell and colleagues, at Beth Israel Deaconess Medical Centre in Boston, used DREADD technology (designer receptors exclusively activated by designer drugs) to specifically control the activation and deactivation of this population in mice. They found that chronic stimulation of AgRP neurones induced weight gain related to an increase in food intake. Similarly, inhibition of this neuronal population inhibited food intake. Furthermore, stimulation of AgRP neurones induced an intense, unrelenting food seeking behaviour. The researchers believe that this study demonstrates that AgRP neurones are critical regulators of a behavioural program that drives individuals to find and consume food.