['Chronic central administration of neuropeptide Y (NPY) has dramatic effects on energy balance; however, the exact role of the hypothalamic paraventricular nucleus (PVN) in this is unknown. The aim of this study was to further unravel the contribution of NPY signaling in the PVN to energy balance.', 'Recombinant adeno-associated viral particles containing NPY (rAAV-NPY) were injected in the rat brain with coordinates targeted at the PVN. For three weeks, body weight, food intake, endocrine parameters, body temperature, and locomotor activity were measured. Furthermore, effects on insulin sensitivity and expression of NPY, agouti-related protein (AgRP), and pro-opiomelanocortin in the arcuate nucleus were studied.', 'Food intake was increased specifically in the light period, and dark phase body temperature and locomotor activity were reduced. This resulted in obesity characterized by increased fat mass; elevated plasma insulin, leptin, and adiponectin; decreased AgRP expression in the arcuate nucleus; and decreased insulin sensitivity; whereas plasma corticosterone was unaffected.'] Does viral mediated neuropeptide Y expression in the rat paraventricular nucleus result in obesity?