Search results
Results From The WOW.Com Content Network
Many of its neurons project to the posterior pituitary where they secrete oxytocin, and a smaller amount of vasopressin. Other secretions are corticotropin-releasing hormone (CRH) and thyrotropin-releasing hormone (TRH). [1] CRH and TRH are secreted into the hypophyseal portal system, and target different neurons in the anterior pituitary.
An increase in vasopressin has been observed in female rats which have just given birth. Vasopressin is associated with aggressive and hostile behaviours, and is postulated to decrease sexual motivation in females. Vasopressin administered in the female rat brain has been observed to result in an immediate decrease in sexual motivation. [13]
Vasopressin regulates the tonicity of body fluids. It is released from the posterior pituitary in response to hypertonicity and causes the kidneys to reabsorb solute-free water and return it to the circulation from the tubules of the nephron, thus returning the tonicity of the body fluids toward normal.
Vasopressin is produced from the vasopressin-producing cells via the AVP gene, a molecular output of circadian pathways. [citation needed] Magnocellular neurosecretory cells in rats (where these neurons have been most extensively studied) in general have a single long varicose axon, which projects to the posterior pituitary.
In 1950, Geoffrey Harris and Barry Cross outlined the oxytocin pathway by studying oxytocin release in response to electrical stimulation. [24] In 1974, Walters and Hatton investigated the effect of water dehydration by electrically stimulating the supraoptic nucleus—the hypothalamic center responsible for the release of vasopressin. [ 24 ]
The well known antidiuretic effect of vasopressin occurs via activation of V 2 R. [1] Vasopressin regulates water excretion from the kidney by increasing the osmotic water permeability of the renal collecting duct – an effect that is explained by coupling of the V 2 R with the G s signaling pathway, which activates cAMP.
An antidiuretic is a substance that helps to control fluid balance in an animal's body by reducing urination, [1] opposing diuresis. [2] Its effects are opposite that of a diuretic. The major endogenous antidiuretics are antidiuretic hormone (ADH; also called vasopressin) and oxytocin.
The oxytocin and vasopressin that is released at the posterior pituitary gland enters the blood, and cannot re-enter the brain because the blood–brain barrier does not allow oxytocin and vasopressin through, but the oxytocin and vasopressin that is released from dendrites acts within the brain. Oxytocin neurons themselves express oxytocin ...