vasopressin V2 receptor

DEFINITION:

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

V2R

DEFINITION:

Vasopressin-2 receptor.

mRNA

DEFINITION:

Messenger RNA. RNA molecules, usually 400 to 10,000 bases long, that serve as templates for protein synthesis (translation); in eukaryotes they have characteristic posttranscriptional modifications, the 5'-cap and poly A tail. The base sequence of an mRNA transcript completely specifies the corresponding polypeptide amino acid sequence.

AVP

DEFINITION:

Arginine vasopressin.

elucidate

DEFINITION:

To make lucid (clear) especially by explanation or analysis; to give a clarifying explanation.

AVP

DEFINITION:

Arginine vasopressin.

Northern blot analysis

DEFINITION:

A technique analogous to Southern blot technique, but performed on fragments of RNA instead of DNA; a nylon membrane is often substituted for the nitrocellulose filter.

7 transmembrane domain

DEFINITION:

The seventh region (domain) of the transmembrane V2R. See schematic drawing of the V2R.

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.

AQP2

DEFINITION:

Aquaporin-2.

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).

V2R

DEFINITION:

Vasopressin-2 receptor.

mRNA

DEFINITION:

Messenger RNA. RNA molecules, usually 400 to 10,000 bases long, that serve as templates for protein synthesis (translation); in eukaryotes they have characteristic posttranscriptional modifications, the 5'-cap and poly A tail. The base sequence of an mRNA transcript completely specifies the corresponding polypeptide amino acid sequence.

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).

V2R

DEFINITION:

Vasopressin-2 receptor.

mRNA

DEFINITION:

Messenger RNA. RNA molecules, usually 400 to 10,000 bases long, that serve as templates for protein synthesis (translation); in eukaryotes they have characteristic posttranscriptional modifications, the 5'-cap and poly A tail. The base sequence of an mRNA transcript completely specifies the corresponding polypeptide amino acid sequence.

permission

DEFINITION:

Formal consent; authorization.