Citizendia

natriuretic peptide precursor A
Identifiers
SymbolNPPA
Alt. SymbolsANP, PND
Entrez4878
HUGO7939
OMIM108780
RefSeqNM_006172
UniProtP01160
Other data
LocusChr. 1 p36.21

Atrial natriuretic peptide (ANP), atrial natriuretic factor (ANF), or atriopeptin, is a polypeptide hormone secreted by atrial myocytes that is involved in the homeostatic control of body water, sodium, potassium and adiposity. The Entrez Global Query Cross-Database Search System is a powerful Federated search engine or Web portal that allows users to search many discrete Health sciences The Human Genome Organisation (HUGO is an organization involved in the Human Genome Project, a project about mapping the human genome The Mendelian Inheritance in Man project is a Database that catalogues all the known Diseases with a genetic component, and—when possible—links them The National Center for Biotechnology Information ( NCBI) is part of the United States National Library of Medicine (NLM a branch of the National Institutes Swiss-Prot is a manually curated Biological database of Protein sequences In the fields of Genetics and Evolutionary computation, a locus (plural loci) is a fixed position on a Chromosome such as the position of a Chromosome 1 is the designation for the largest Human Chromosome. Peptides (from the Greek πεπτίδια, "small digestibles" are short Polymers formed from the linking in a defined order of α- Amino Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body The cardiac muscle is a type of involuntary striated Muscle found in the walls of the Heart. Homeostasis (from Greek: ὅμος hómos, "equal" and ιστημι istēmi, "to stand" lit Water is a common Chemical substance that is essential for the survival of all known forms of Life. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 "Adipose" redirects here For the Doctor Who monster see " Partners in Crime " It is released by atrial myocytes, muscle cells in the atria of the heart, in response to high blood pressure. Skeletal muscle is a type of Striated muscle, which usually attaches to tendons In Anatomy, the atrium (plural atria) refers to a chamber or space ANP acts to reduce the water, sodium and adipose loads on the circulatory system, thereby reducing blood pressure.

Contents

Structure

ANP is a 28-amino acid peptide with a 17-amino acid ring in the middle of the molecule. The ring is formed by a disulfide bond between two cysteine residues at positions 7 and 23. Not to be confused with Cystine, its oxidized dimer Cysteine (abbreviated as Cys or C) is an α- Amino acid with ANP is closely related to BNP (brain natriuretic peptide) and CNP (C-type natriuretic peptide), which all share the same amino acid ring. Brain natriuretic peptide (BNP also known as B-type natriuretic peptide (also BNP or GC-B, is a 32 amino acid polypeptide secreted by the ventricles C-type natriuretic peptide (CNP is a 22 Amino acid Peptide that has strong Vasorelaxant properties ANP was discovered in 1981 by a team in Kingston, Canada led by Adolfo J. Year 1981 ( MCMLXXXI) was a Common year starting on Thursday (link displays the 1981 Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page de Bold after they made the seminal observation that injection of atrial (but not ventricular) tissue extracts into rats caused copious natriuresis. [1]

Production

ANP is produced, stored and released by cardiac myocytes of the atria of the heart. The cardiac muscle is a type of involuntary striated Muscle found in the walls of the Heart. It is released in response to atrial stretch and a variety of other signals induced by hypervolemia, exercise or caloric restriction. The hormone is constitutively expressed in the ventricle in response to stress induced by increased afterload (eg. increased ventricular pressure from aortic stenosis) or injury (eg. myocardial infarction).

ANP is secreted in response to:

The atria become distended by high extracellular fluid and blood volume, and atrial fibrillation. The Sympathetic Nervous System ( SNS) is a branch of the Autonomic nervous system along with the Enteric nervous system and Parasympathetic nervous The adrenergic receptors (or adrenoceptors) are a class of G protein-coupled receptors that are targets of the Catecholamines Adrenergic receptors Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Hypernatremia is an Electrolyte disturbance that is defined by an elevated Sodium level in the blood Angiotensin causes blood vessels to constrict and drives blood pressure up Endothelins are proteins that constrict blood vessels and raise blood pressure Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles Atrial fibrillation ( AF or afib) is a Cardiac arrhythmia (abnormal heart rhythm that involves the two upper chambers ( atria) of the Heart Notably, ANP secretion increases in response to immersion of the body in water, which causes atrial stretch due to an altered distribution of intravascular fluid. ANP secretion in response to exercise has also been demonstrated in horses. The horse ( Equus caballus) is a hoofed ( Ungulate) Mammal, one of eight living species of the family Equidae.

Receptors

Three cell surface receptors have so far been identified on which ANP act, and these are designated ANPA, ANPB and ANPC. Transmembrane receptors are Integral membrane proteins which reside and operate typically within a cell's Plasma membrane, but also in the membranes of The ANPA and ANPB receptors have guanylate cyclase activity and mediate the biological effects by producing cGMP. Guanylate cyclase ( also known as guanylyl cyclase or GC) is a Lyase Enzyme. The ANPC receptor functions mainly as a clearance receptor by binding and sequestering ANP from the circulation. All natriuretic peptides are bound by the ANPC receptor. Atrial natriuretic peptide and brain natriuretic peptide act through the ANPA and C-type natriuretic peptide through the ANPB receptor [2]

Physiological effects

ANP binds to a specific set of receptors - ANP receptors. Brain natriuretic peptide (BNP also known as B-type natriuretic peptide (also BNP or GC-B, is a 32 amino acid polypeptide secreted by the ventricles C-type natriuretic peptide (CNP is a 22 Amino acid Peptide that has strong Vasorelaxant properties In Biochemistry, a receptor is a Protein molecule embedded in either the Plasma membrane or Cytoplasm of a cell to which a mobile signaling A atrial natriuretic peptide receptor is a receptor for Atrial natriuretic peptide. Receptor-agonist binding causes a reduction in blood volume and therefore a reduction in cardiac output and systemic blood pressure. An agonist is a term used to describe a type of ligand or drug that binds and alters the activity of a receptor. Lipolysis is increased and renal sodium reabsorption is decreased. Lipolysis is the breakdown of fat stored in fat cells During this process Free fatty acids are released into the bloodstream and circulate throughout the body Renal reabsorption of sodium ( Na+) is a part of Renal physiology. The overall effect of ANP on the body is to counter increases in blood pressure and volume caused by the renin-angiotensin system. The renin-angiotensin system (RAS or the renin-angiotensin-aldosterone system (RAAS is a hormone system that regulates Blood pressure and water ( fluid

Renal

Vascular

Cardiac

Adipose tissue

Degradation

Regulation of the effects of ANP is achieved through gradual degradation of the peptide by the enzyme neutral endopeptidase (NEP). A atrial natriuretic peptide receptor is a receptor for Atrial natriuretic peptide. cGMP-dependent protein kinase or Protein Kinase G (PKG is a Serine/threonine-specific protein kinase that is activated by cGMP. Recently NEP inhibitors have been developed, although they have not yet been licensed. They may be clinically useful in treating congestive heart disease.

Other natriuretic factors

In addition to the mammalian natriuretic peptides (ANP, BNP, CNP), two others have been isolated. Tervonen (1998) described a salmon natriuretic peptide, named Salmon cardiac peptide, with similar structure and properties[3]. Salmon is the common name for several species of Fish of the family Salmonidae. As well, dendroaspis natriuretic peptide (DNP) was discovered in the venom of the green mamba by Schweitz et al. MAMBA stands for Mobile Artillery Monitoring Battlefield Asset, a Counter-battery radar operated by the Royal Artillery. MAMBA stands for Mobile Artillery Monitoring Battlefield Asset, a Counter-battery radar operated by the Royal Artillery. (1992).

Diagnostic Use

Used in conjunction with other clinical information, measurement of B-type natriuretic peptide (BNP) can help determine whether a patient's dyspnea is caused by congestive heart failure in which BNP levels are elevated. Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply This laboratory test has become a valuable and quick method for diagnostic work-up of patients presenting to the emergency department (ED) with acute dyspnea.

Pharmacological modulation

Neutral endopeptidase (NEP) is the enzyme that metabolizes natriuretic peptides. Several inhibitors of NEP are currently being developed to treat disorders ranging from hypertension to heart failure. Most of them are dual inhibitors. Omapatrilat (dual inhibitor of NEP and angiotensin converting enzyme) developed by BMS did not receive FDA approval due to angioedema safety concerns. Other dual inhibitors of NEP with ACE / angiotensin receptor are currently being developed by pharmaceutical companies. [4]

See also

References

  1. ^ de Bold A (1985). Brain natriuretic peptide (BNP also known as B-type natriuretic peptide (also BNP or GC-B, is a 32 amino acid polypeptide secreted by the ventricles "Atrial natriuretic factor: a hormone produced by the heart. ". Science 230 (4727): 767-70. PMID 2932797.  
  2. ^ ANP
  3. ^ Tervonen et al. , 1998 Endocrinology 139:4021-4025.
  4. ^ [1] Joshi Venugopal. (2003) Pharmacological modulation of the natriuretic peptide system. Expert Opinion on Therapeutic Patents 13:9, 1389

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