5-Hydroxytryptamine receptor 4 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''HTR4''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Function

This gene is a member of the family of human

serotonin Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, ...

receptors, which are

G protein-coupled receptors G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large protein family, group of evoluti ...

that stimulate

cAMP Camp may refer to: Areas of confinement, imprisonment, or for execution * Concentration camp, an internment camp for political prisoners or politically targeted demographics, such as members of national or minority ethnic groups * Extermination ...

production in response to serotonin (5-hydroxytryptamine). The gene product is a glycosylated transmembrane protein that functions in both the peripheral and central nervous system to modulate the release of various

neurotransmitters A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotransmitters are rele ...

. Multiple transcript variants encoding proteins with distinct C-terminal sequences have been described, but the full-length nature of some transcript variants has not been determined.

Location

The receptor is located in the

alimentary tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

urinary bladder The bladder () is a hollow organ in humans and other vertebrates that stores urine from the Kidney (vertebrates), kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. In humans, the ...

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

and

adrenal gland The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer adrenal corte ...

as well as the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

(CNS). In the CNS the receptor appears in the

putamen The putamen (; from Latin, meaning "nutshell") is a subcortical nucleus (neuroanatomy), nucleus with a rounded structure, in the basal ganglia nuclear group. It is located at the base of the forebrain and above the midbrain. The putamen and c ...

caudate nucleus The caudate nucleus is one of the structures that make up the corpus striatum, which is part of the basal ganglia in the human brain. Although the caudate nucleus has long been associated with motor processes because of its relation to Parkinso ...

nucleus accumbens The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for ' nucleus adjacent to the septum') is a region in the basal forebrain rostral to the preoptic area of the hypo ...

globus pallidus The globus pallidus (GP), also known as paleostriatum or dorsal pallidum, is a major component of the Cerebral cortex, subcortical basal ganglia in the brain. It consists of two adjacent segments, one external (or lateral), known in rodents simpl ...

, and

substantia nigra The substantia nigra (SN) is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. ''Substantia nigra'' is Latin for "black substance", reflecting the fact that parts of the substantia nigra a ...

, and to a lesser extent in the

neocortex The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such as sensory perception, cognition, generation of motor commands, ...

raphe Raphe ( ; from ;Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with the assistance of. Roderick McKenzie.'' Oxford: Clarendon Press. : raphae or raphes) has several differe ...

pontine nuclei The pontine nuclei (or griseum pontis) are all the neurons of the ventral pons. Corticopontine fibres project from the primary motor cortex to the ipsilateral pontine nucleus; pontocerebellar fibers then relay the information to the contralater ...

, and some areas of the

thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...

. It has not been found in the cerebellum.

Isoforms

Internalization is isoform-specific.

Ligands

Several drugs that act as 5-HT₄ selective agonists have recently been introduced into use in both scientific research and clinical medicine. Some drugs that act as 5-HT₄ agonists are also active as 5-HT₃ antagonists, such as mosapride, metoclopramide, renzapride, and zacopride, and so these compounds cannot be considered highly selective. Research in this area is ongoing. Amongst these agonists

prucalopride Prucalopride, sold under brand names Resolor and Motegrity among others, is a medication acting as a selective, high affinity 5-HT4 receptor agonist which targets the impaired motility associated with chronic constipation, thus normalizing bow ...

has >150-fold higher affinity for 5-HT4 receptors than for other receptors. SB-207,145 radiolabeled with

carbon-11 Carbon (6C) has 14 known isotopes, from to as well as , of which only and are stable nuclide, stable. The longest-lived radionuclide, radioisotope is , with a half-life of years. This is also the only carbon radioisotope found in nature, as ...

is used as a

radioligand A radioligand is a microscopic particle which consists of a Radiopharmaceutical, therapeutic radioactive isotope and the cell-targeting compound - the ligand. The ligand is the target binding site, it may be on the surface of the targeted cancer c ...

for 5-HT₄ in

positron emission tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, r ...

pig and human studies.

Agonists

Tropisetron Tropisetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic to treat nausea and vomiting following chemotherapy, although it has been used experimentally as an analgesic in cases of fibromyalgia. It was patented in 198 ...

partial agonist *

BIMU-8 BIMU-8 is a drug which acts as a 5-HT4 receptor selective agonist. BIMU-8 was one of the first compounds of this class. The main action of BIMU-8 is to increase the rate of respiration by activating an area of the brain stem known as the pre-B ...

Cisapride Cisapride is a gastroprokinetic agent, a drug that increases motility in the upper gastrointestinal tract. It acts directly as a serotonin 5-HT4 receptor agonist and indirectly as a parasympathomimetic. Stimulation of the serotonin receptors incr ...

CJ-033,466 CJ-033466 is a drug which acts as a potent and selective 5-HT4 serotonin receptor partial agonist. In animal tests it stimulated gastrointestinal motility with 30 times the potency of cisapride, and with lower affinity for the hERG channel. S ...

partial agonist *

Felcisetrag Felcisetrag (TAK-954, TD-8954) is a drug which acts as a potent and highly selective agonist for the serotonin receptor 5-HT4. It is in clinical trials for the treatment of gastroparesis Gastroparesis (gastro- from Ancient Greek – gast ...

ML-10302 ML-1 was an experimental nuclear reactor built as part of the US Army Nuclear Power Program between 1961 and 1965. It was intended to provide truck-mounted nuclear power that could accompany troops from place to place and provide power to comma ...

Mosapride Mosapride is a gastroprokinetic agent that acts as a selective 5HT4 agonist. The major active metabolite of mosapride, known as M1, additionally acts as a 5HT3 antagonist, which accelerates emptying throughout the whole of the gastrointestinal ...

Prucalopride Prucalopride, sold under brand names Resolor and Motegrity among others, is a medication acting as a selective, high affinity 5-HT4 receptor agonist which targets the impaired motility associated with chronic constipation, thus normalizing bow ...

Renzapride Renzapride is a prokinetic agent and antiemetic which acts as a full 5-HT4 agonist and partial 5-HT3 antagonist. It also functions as a 5-HT2B antagonist and has some affinity for the 5-HT2A and 5-HT2C receptors. Renzapride was being develo ...

* RS-67506 * RS-67333 partial agonist * SL65.0155 partial agonist *

Tegaserod Tegaserod is a 5-HT4 agonist manufactured by Novartis and sold under the names Zelnorm and Zelmac for the management of irritable bowel syndrome and constipation. Approved by the FDA in 2002, it was subsequently removed from the market in 2007 d ...

Zacopride Zacopride is a potent antagonist at the 5-HT3 receptor and an agonist at the 5-HT4 receptor. It has anxiolytic and nootropic effects in animal models, with the (''R'')-(+)-enantiomer being the more active form. It also has antiemetic and pro-re ...

Metoclopramide Metoclopramide is a medication used to treat nausea, vomiting, gastroparesis, and gastroesophageal reflux disease. It is also used to treat migraine headaches. Common side effects include feeling tired, diarrhea, akathisia, and tardive dyski ...

Sulpiride Sulpiride, sold under the brand name Dogmatil among others, is an atypical antipsychotic (although some texts have referred to it as a typical antipsychotic) medication of the benzamide class which is used mainly in the treatment of psychosi ...

* Naronapride * Usmarapride

Antagonists

L-lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group (wh ...

* Piboserod * GR-113,808 (1-methyl-1H-indole-3-carboxylic acid, -[2-[(methylsulfonyl)aminothyl">-[(methylsulfonyl)amino.html" ;"title="-[2-[(methylsulfonyl)amino">-[2-[(methylsulfonyl)aminothyl4-piperidinyl]methyl ester) * GR-125,487 * RS-39604 (1-[4-Amino-5-chloro-2-(3,5-dimethoxyphenyl)methyloxy]-3-[1-[2-methylsulphonylamino]piperidin-4-yl]propan-1-one) * SB-203,186 * SB-204,070 *([Methoxy-¹¹C]1-butylpiperidin-4-yl)methyl 4-amino-3-methoxybenzoate * Chamomile (ethanol extract)

References

External links

* * {{DEFAULTSORT:5-Ht4 Receptor Biology of bipolar disorder Serotonin receptors