AVP neurons in the paraventricular nucleus of the hypothalamus regulate feeding.

Melanocortins and their receptors are critical components of energy homeostasis and the paraventricular nucleus of the hypothalamus (PVH) is an important site of melanocortin action. Although best known for its role in osmoregulation, arginine vasopressin (AVP) has been implicated in feeding and is robustly expressed in the PVH. Since the anorectic melanocortin agonist MTII activates PVH-AVP neurons, we hypothesized that PVH-AVP neurons contribute to PVH-mediated anorexia. To test this, we used an AVP-specific Cre-driver mouse in combination with viral vectors to acutely manipulate PVH-AVP neuron function. Using designer receptors exclusively activated by designer drugs (DREADDs) to control PVH-AVP neuron activity, we show that activation of PVH-AVP neurons acutely inhibits food intake, whereas their inhibition partially reverses melanocortin-induced anorexia. We further show that MTII fails to fully suppress feeding in mice with virally-induced PVH-AVP neuron ablation. Thus PVH-AVP neurons contribute to feeding behaviors, including the acute anorectic response to MTII.