Energy homeostasis: Paraventricular nucleus system

The hypothalamic paraventricular nucleus (PVN) plays a multifaceted role in neuroendocrine, autonomic and behavioral regulation by controlling the activity of key hypothalamic-pituitary-target organ systems, including the corticotropic and thyrotropic axes. In this updated article, we discuss the fundamental and emerging roles of the PVN in the regulation of energy balance. We focus on the importance of the parvocellular neurosecretory system, which hosts the corticotropin-releasing factor (CRF) and thyrotropin-releasing hormone (TRH) neurons, and the magnocellular neurosecretory division, which includes neurons that synthesize vasopressin and oxytocin, in the neuroendocrine control of energy homeostasis. We also address the importance of the arcuate nucleus (ARC)-PVN pathway in energy balance regulation, with a critical emphasis on the melanocortin system. We further discuss the PVN ascending pathways that innervate the brainstem and spinal cord and that coordinate autonomic and behavioral responses.