Tuesday, November 10, 2009

Paraventricular Nucleus

The paraventricular nucleus, or PVN, is a group of neurons in the hypothalamus. It is associated with the rear lobe of the pituitary gland. Within the paraventricular nucleus there are multiple subpopulations of neurons which are activated by a variety of physiological changes. About 40% of paraventricular nucleus neurons project directly to the posterior lobe of the pituitary, releasing oxytocin or vasopressin into the general circulation. Other PVN neurons control various anterior pituitary functions, while still others directly regulate appetite and autonomic functions in the brainstem and spinal cord.

The paraventricular nucleus lies alongside the third ventricle; hence its name, "paraventricular" meaning "alongside a ventricle." The PVN is highly vascularized and is protected by the blood-brain barrier, although its neuroendocrine neurons extend to sites beyond the blood-brain barrier.