Posterior Pituitary Hormones and Pain

Vasopressin and oxytocin are well-known neurohypophysial and posterior pituitary hormones that are synthesized in the paraventricular and supraoptic nuclei of the hypothalamus and are secreted from the posterior pituitary into the systemic circulation. It is known that vasopressin plays an important role in maintaining body fluid homeostasis, and that oxytocin plays an essential role in mammalian labor and lactation through its peripheral action. In addition to these classic physiological actions, vasopressin and oxytocin have been attracting considerable attention in recent years because of their effects in their involvement in social recognition, and in the regulation of the cardiovascular system, the central nervous system and stress responses. Their analgesic effects have also been mentioned among these newly-recognized physiological actions. This review focuses on pain modulation by vasopressin and oxytocin.