Vasoactive intestinal peptide
Encyclopedia
Vasoactive intestinal peptide also known as the vasoactive intestinal polypeptide or VIP is a peptide hormone
containing 29 amino acid
residue
s that is produced in many tissues of vertebrate
s including the gut
, pancreas
and suprachiasmatic nuclei of the hypothalamus
in the brain
. VIP stimulates contractility
in the heart, causes vasodilation
, increases glycogenolysis
, lowers arterial blood pressure
and relaxes the smooth muscle of trachea
, stomach and gall bladder. In humans, the vasoactive intestinal peptide is encoded by the VIP gene
.
VIP has a half-life
(T1/2) in the blood of about two minutes.
.
Can be associated with Multiple Endocrine Neoplasia Type 1
(Pituitary, parathyroid and pancreatic tumors).
Symptoms are typically:
Peptide hormone
Peptide hormones are a class of peptides that are secreted into the blood stream and have endocrine functions in living animals.Like other proteins, peptide hormones are synthesized in cells from amino acids according to an mRNA template, which is itself synthesized from a DNA template inside the...
containing 29 amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
residue
Residue (chemistry)
In chemistry, residue is the material remaining after a distillation or an evaporation, or to a portion of a larger molecule, such as a methyl group. It may also refer to the undesired byproducts of a reaction....
s that is produced in many tissues of vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s including the gut
Gut (zoology)
In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...
, pancreas
Pancreas
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...
and suprachiasmatic nuclei of the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
in the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
. VIP stimulates contractility
Contractility
Myocardial contractility is the intrinsic ability of the heart to contract independent of preload and afterload. Changes in the ability to produce force during contraction result from different degrees of binding between myosin and actin filaments...
in the heart, causes vasodilation
Vasodilation
Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
, increases glycogenolysis
Glycogenolysis
Glycogenolysis is the conversion of glycogen polymers to glucose monomers. Glycogen is catabolized by removal of a glucose monomer through cleavage with inorganic phosphate to produce glucose-1-phosphate...
, lowers arterial blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
and relaxes the smooth muscle of trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
, stomach and gall bladder. In humans, the vasoactive intestinal peptide is encoded by the VIP gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
VIP has a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
(T1/2) in the blood of about two minutes.
Function
VIP has an effect on several tissues:- With respect to the digestive system, VIP seems to induce smooth muscleSmooth muscleSmooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
relaxation (lower esophageal sphincter, stomachStomachThe stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
, gallbladderGallbladderIn vertebrates the gallbladder is a small organ that aids mainly in fat digestion and concentrates bile produced by the liver. In humans the loss of the gallbladder is usually easily tolerated....
), stimulate secretion of water into pancreatic juicePancreatic juicePancreatic juice is a liquid secreted by the pancreas, which contains a variety of enzymes, including trypsinogen, chymotrypsinogen, elastase, carboxypeptidase, pancreatic lipase, and amylase....
and bileBileBile or gall is a bitter-tasting, dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the process of digestion of lipids in the small intestine. In many species, bile is stored in the gallbladder and upon eating is discharged into the duodenum...
, and cause inhibition of gastric acidGastric acidGastric acid is a digestive fluid, formed in the stomach. It has a pH of 1 to 2 and is composed of hydrochloric acid , and large quantities of potassium chloride and sodium chloride...
secretion and absorption from the intestinal lumen. Its role in the intestineIntestineIn human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
is to greatly stimulate secretion of water and electrolytes, as well as stimulating contraction of enteric smooth muscleSmooth muscleSmooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
, dilating peripheral blood vessels, stimulating pancreatic bicarbonateBicarbonateIn inorganic chemistry, bicarbonate is an intermediate form in the deprotonation of carbonic acid...
secretion, and inhibiting gastrinGastrinIn humans, gastrin is a peptide hormone that stimulates secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the antrum of the stomach, duodenum, and the pancreas...
-stimulated gastric acidGastric acidGastric acid is a digestive fluid, formed in the stomach. It has a pH of 1 to 2 and is composed of hydrochloric acid , and large quantities of potassium chloride and sodium chloride...
secretion. These effects work together to increase motility.
- It also has the function of stimulating pepsinogen secretion by chief cellsGastric chief cellA gastric chief cell is a cell in the stomach that releases pepsinogen, gastric lipase and Chymosin...
.
- It is also found in the brainBrainThe brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
and some autonomicAutonomic nervous systemThe autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...
nerves. One region of the brain includes a specific area of the suprachiasmatic nuclei (SCN), the location of the 'master circadian pacemaker'. The SCN coordinates daily timekeeping in the body and VIP plays a key role in communication between individual brain cells within this region. Further, VIP is also involved in synchronising the timing of SCN function with the environmental light-dark cycle. Combined, these roles in the SCN make VIP a crucial component of the mammalian circadian timekeeping machinery.
- VIP helps to regulate prolactinProlactinProlactin also known as luteotropic hormone is a protein that in humans is encoded by the PRL gene.Prolactin is a peptide hormone discovered by Henry Friesen...
secretion; it stimulates prolactin release in the domestic turkey.
- It is also found in the heartHeartThe heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
and has significant effects on the cardiovascular system. It causes coronary vasodilationVasodilationVasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
as well as having a positive inotropic and chronotropicChronotropicChronotropic effects are those that change the heart rate.Chronotropic drugs may change the heart rate by affecting the nerves controlling the heart, or by changing the rhythm produced by the sinoatrial node...
effect. Research is being performed to see if it may have a beneficial role in the treatment of heart failure.
- VIP provokes vaginal lubrication in normal women, doubling the total volume of lubrication produced in one study.
- GH-RH is a member of the VIP family and stimulates Growth HormoneGrowth hormoneGrowth hormone is a peptide hormone that stimulates growth, cell reproduction and regeneration in humans and other animals. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior...
secretion in the anterior pituitary gland.
Pathology
VIP is overproduced in VIPomaVIPoma
A VIPoma is a rare endocrine tumor, usually originating in the pancreas, that produces vasoactive intestinal peptide ....
.
Can be associated with Multiple Endocrine Neoplasia Type 1
Multiple endocrine neoplasia type 1
Multiple endocrine neoplasia type 1 or Wermer's syndrome is part of a group of disorders that affect the endocrine system.-Explanation:...
(Pituitary, parathyroid and pancreatic tumors).
Symptoms are typically:
- Profuse non-bloody/non-mucoid diarrhoea (3L+) causing dehydration and the associated electrolyte disturbances such as hypokalemiaHypokalemiaHypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...
and contraction metabolic alkalosisMetabolic alkalosisMetabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range . This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations.-Terminology:*Alkalosis...
. - Lethargy and exhaustion may ensue
