vasopressin type 2 receptor

DEFINITION:

The molecular structure within a cell or on the surface to which the antidiuretic hormone, arginine vasopressin, binds.

V2

DEFINITION:

Vasopressin-2. See vasopressin-2 gene and vasopressin-2 receptor.

mediated

DEFINITION:

Accomplished by the aid of an intervening medium.

vasopressin

DEFINITION:

1. One of two octapeptide hormones formed by the neuronal cells of the hypothalamic nuclei and stored in the posterior lobe of the pituitary gland (neurohypophysis), the other being oxytocin. It stimulates the contraction of the muscular tissue of the capillaries and arterioles, raising the blood pressure. It promotes contraction of the intestinal musculature and increases peristalsis, and also exerts some contractile influence on the uterus. It also has a specific effect on the epithelial cells of the distal portion of the uriniferous tubule, augmenting resorption of water independently of solutes, resulting in concentration of urine and dilution of blood serum. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

2. [USP], A pharmaceutical preparation of the same principle, prepared synthetically or obtained from the posterior pituitary of healthy domestic animals used for food by man; used mainly as an antidiuretic in the treatment of acute or chronic diabetes insipidus, administered intramuscularly as a test of hypothalamo-neurohypophysial-renal function in distinguishing central from nephrogenic diabetes insipidus; it may also be used to stimulate smooth muscle tissue, especially to induce vasoconstriction in the presence of hemorrhage. Called also antidiuretic hormone (ADH).

regulated

DEFINITION:

1. Having been adjusted to a certain standard.

2. In biology, describing the adaptation of form or behavior of an organism to changed conditions.

water channel

DEFINITION:

A channel in the plasma membrane of plant and animal cells that permits passage of water molecules; chemical substances such as vasopressin cause the opening of new channels and increase permeability.

aquaporin-2

DEFINITION:

Also called WCH-CD, this water channel makes the principal cells of the inner medullary collecting duct in the kidneys more permeable to water. Lack of functional aquaporin-2 gene leads to a rare form of nephrogenic diabetes insipidus.

AQP-2

DEFINITION:

Aquaporin-2.

ascites

DEFINITION:

Effusion and accumulation of serous fluid in the abdominal cavity; called also abdominal or peritoneal dropsy, hydroperitonia, and hydrops abdominis.

expression

DEFINITION:

1. The aspect or appearance of the face (or surface of a cell) as determined by the physical or emotional state.

2. The act of squeezing or evacuating by pressure; a term used in pharmacy, surgery, and obstetrics.

3. The detectable effect of a gene.

4. A representation of value, relation, or the like (e.g., ratio).

BSC-1

DEFINITION:

Abbreviation for type 1 bumetanide-sensitive Na-K-2Cl cotransporter.

intravenous

DEFINITION:

Within a vein or veins.

test

DEFINITION:

1. An examination or trial.

2. A significant chemical reaction.

3. A reagent.

4. A loose or rigid, secreted or agglutinated, protective shell or shell-like covering or exoskeleton, seen in various invertebrates, including certain protozoa and echinoderms.

V2-receptor blockade

DEFINITION:

See blockade.

V2-receptor blockade

DEFINITION:

See blockade.

selective

DEFINITION:

Having a high degree of selectivity.

antagonist

DEFINITION:

1. A muscle whose action is the direct opposite of that of another muscle.

2. A substance that tends to nullify the action of another, as a drug that binds to a cell receptor without eliciting a biological response, blocking binding of substances that could elicit such responses.

3. A tooth in one jaw that articulates with a tooth in the other jaw.

intravenous

DEFINITION:

Within a vein or veins.

glucose

DEFINITION:

1. A sugar C₆H₁₂O₆ known in dextrorotatory, levorotatory, and racemic forms; esp.: the sweet colorless soluble dextrorotatory form that occurs widely in nature and is the usual form in which carbohydrate is assimilated by animals.

2. A light-colored syrup made from cornstarch.

free water clearance

DEFINITION:

The net amount of solute-free water moved from the blood to the urine; the difference between the urine volume and the osmolal clearance.

control rats

DEFINITION:

A group of rats differing from that under study (the treated or case group) by lacking the disease or by having a different or absent treatment or regimen; the controls and case or treated subjects usually otherwise have certain similarities to allow or enhance comparison between them.

intravenous

DEFINITION:

Within a vein or veins.

test

DEFINITION:

1. An examination or trial.

2. A significant chemical reaction.

3. A reagent.

4. A loose or rigid, secreted or agglutinated, protective shell or shell-like covering or exoskeleton, seen in various invertebrates, including certain protozoa and echinoderms.

affect

DEFINITION:

1. To produce an effect on; influence.

2. The external expression of emotion attached to ideas or mental representations of objects.

cirrhotic

DEFINITION:

Pertaining to or characterized by cirrhosis.

control rats

DEFINITION:

A group of rats differing from that under study (the treated or case group) by lacking the disease or by having a different or absent treatment or regimen; the controls and case or treated subjects usually otherwise have certain similarities to allow or enhance comparison between them.

downregulation

DEFINITION:

A decrease in the number of receptors for a chemical or drug on cell surfaces in a given area, usually due to long-term exposure to the agent. (Dorland's Illustrated Medical Dictionary, 29th edition)

Downregulation of aquaporin 2: The number of aquaporin 2 water channels will be decreased, i.e., regulated to a lower number of channels expressed on the luminal membrane (D. Bichet).

Downregulation of AQP2 means that there are many conditions with acquired nephrogenic diabetes insipidus (vasopressin-resistent polyuria) which result in a reduction in the levels of AQP2 protein in the collecting duct cells. Since AQP2 is essential for reabsorption of water from the collecting duct lumen back to the circulation, the absence or reduced levels of AQP2 (downregulation) results in the development of polyuria. Thus the conditions associated with this downregulation of AQP2 share many common features with the inherited forms of NDI (with mutations in vasopressin V2 receptor) since this condition is also associated with a reduced/absence of regulation of AQP2. This regulation is important for keeping the levels of AQP2 protein up, but it is also extremely important in regulating the trafficking of AQP2 from the reservoir in small vesicles to the apical plasma membrane (its active site for water reabsorption—the site where the water channel faces the water to be reabsorbed). This is why the studies of the very common acquired forms of NDI are very important in connection with inherited NDI (the shared elements of regulation or rather dysregulation) (S. Nielsen).

AQP-2

DEFINITION:

Aquaporin-2.

renal cortex

DEFINITION:

Kidney cortex (cortex renalis). The outer part of the substance of the kidney, composed mainly of glomeruli and convoluted tubules.

outer medulla

DEFINITION:

See outer medulla of kidney.

relative

DEFINITION:

1. A thing having a relation to or a dependence upon another thing.
2. A person connected with another by blood or marriage.
3. Pertinent, relevant.
4. Not absolute or independent; comparative.
5. Expressed as the ratio of the specified quantity to the total magnitude or to the mean of all quantities involved.

expression

DEFINITION:

1. The aspect or appearance of the face (or surface of a cell) as determined by the physical or emotional state.

2. The act of squeezing or evacuating by pressure; a term used in pharmacy, surgery, and obstetrics.

3. The detectable effect of a gene.

4. A representation of value, relation, or the like (e.g., ratio).

BSC-1

DEFINITION:

Abbreviation for type 1 bumetanide-sensitive Na-K-2Cl cotransporter.

outer medulla

DEFINITION:

See outer medulla of kidney.

cirrhotic

DEFINITION:

Pertaining to or characterized by cirrhosis.

vasopressin

DEFINITION:

1. One of two octapeptide hormones formed by the neuronal cells of the hypothalamic nuclei and stored in the posterior lobe of the pituitary gland (neurohypophysis), the other being oxytocin. It stimulates the contraction of the muscular tissue of the capillaries and arterioles, raising the blood pressure. It promotes contraction of the intestinal musculature and increases peristalsis, and also exerts some contractile influence on the uterus. It also has a specific effect on the epithelial cells of the distal portion of the uriniferous tubule, augmenting resorption of water independently of solutes, resulting in concentration of urine and dilution of blood serum. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

2. [USP], A pharmaceutical preparation of the same principle, prepared synthetically or obtained from the posterior pituitary of healthy domestic animals used for food by man; used mainly as an antidiuretic in the treatment of acute or chronic diabetes insipidus, administered intramuscularly as a test of hypothalamo-neurohypophysial-renal function in distinguishing central from nephrogenic diabetes insipidus; it may also be used to stimulate smooth muscle tissue, especially to induce vasoconstriction in the presence of hemorrhage. Called also antidiuretic hormone (ADH).

mediated

DEFINITION:

Accomplished by the aid of an intervening medium.

water reabsorption

DEFINITION:

1. The act or process of absorbing water again.

2. Resorption.

NaCl

DEFINITION:

Sodium chloride.

reabsorption

DEFINITION:

The act or process of absorbing again, as the selective absorption by the kidneys of substances (glucose, proteins, sodium, etc.) already secreted into the renal tubules, and their return to the circulating blood.

thick ascending limb of Henle

DEFINITION:

See "loop of Henle."

permission

DEFINITION:

Formal consent; authorization.