Evidence that Agrp Neuron Activation Drives Cold-Induced Hyperphagia

Although hyperphagic feeding during cold exposure is widely viewed as a response to the negative energy state that results from increased thermogenesis, the underlying mechanisms are unknown. We investigated an alternative hypothesis, that during cold exposure, hyperphagia is mounted in anticipation of homeostatic need, rather than as a compensatory response. In support of this hypothesis, we report that in chow-fed mice acutely housed at 14°C, increases of food intake and thermogenesis occur both rapidly and simultaneously, implying hyperphagia is not mounted as a compensatory response. We next asked whether this cold-induced feeding response involves activation of agouti-related peptide (Agrp) neurons, which are implicated in other forms of hyperphagic feeding. Consistent with this hypothesis, we report that Agrp neurons are activated within 1-2 min of cold exposure and prior to the onset of …