Nutritive, Post-ingestive Signals Are the Primary Regulators of AgRP Neuron Activity

Abstract

The brain regulates food intake by processing sensory cues and peripheral physiological signals, but the neural basis of this integration remains unclear. Hypothalamic, agouti-related protein (AgRP)-expressing neurons are critical regulators of food intake. AgRP neuron activity is high during hunger and is rapidly reduced by the sight and smell of food. Here, we reveal two distinct components of AgRP neuron activity regulation: a rapid but transient sensory-driven signal and a slower, sustained calorie-dependent signal. We discovered that nutrients are necessary and sufficient for sustained reductions in AgRP neuron activity and that activity reductions are proportional to the calories obtained. This change in activity is recapitulated by exogenous administration of gut-derived satiation signals. Furthermore, we showed that the nutritive value of food trains sensory systems-in a single trial-to drive rapid, anticipatory AgRP neuron activity inhibition. Together, these data demonstrate that nutrients are the primary regulators of AgRP neuron activity.

Keywords: AgRP neurons; CCK; PYY; amylin; calcium imaging; calories; cholecystokinin; homeostasis; peptide tyrosine tyrosine; satiation signals; sensory regulation; single trial learning.