[Distribution and function of angiotensin II receptor subtypes--central nervous system]

AT1 receptors are predominant in the brain of monkeys and rabbits, while AT2 receptors are relatively abundant in the rat brain. In the human brain, all of the angiotensin II receptors in the forebrain, midbrain, pons, medulla and spinal cord are AT1 receptors, and AT2 receptors are found only in the cerebellum. Angiotensin II in the brain increases water and sodium intake, raises blood pressure, attenuates baro-reflex function, and increases vasopressin secretion. These cardiovascular actions of angiotensin II are exclusively mediated by AT1 receptors. Since the mice whose AT2 receptors are knocked out show the increase in blood pressure, the decrease in body temperature, and some alterations in behavior, these receptors may also play roles in the central nervous system.