5-hydroxytryptamine receptor 1B also known as the 5-HT_1B receptor is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...

that in humans is encoded by the ''HTR1B''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. The 5-HT_1B receptor is a 5-HT receptor subtype.

Tissue distribution and function

5-HT_1B receptors are widely distributed throughout the

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

with the highest concentrations found in the frontal cortex, basal ganglia,

striatum The striatum, or corpus striatum (also called the striate nucleus), is a nucleus (a cluster of neurons) in the subcortical basal ganglia of the forebrain. The striatum is a critical component of the motor and reward systems; receives glutamate ...

, and the hippocampus. The function of the 5-HT_1B receptor differs depending upon its location. In the frontal cortex, it is believed to act as a postsynaptic receptor inhibiting the release of dopamine. In the basal ganglia and the striatum, evidence suggests 5-HT signaling acts on an autoreceptor, inhibiting the release of

serotonin Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vas ...

and decreasing glutamatergic transmission by reducing miniature excitatory postsynaptic potential (mEPSP) frequency, respectively. In the hippocampus, a recent study has demonstrated that activation of postsynaptic 5-HT_1B heteroreceptors produces a facilitation in excitatory synaptic transmission which is altered in depression. When the expression of 5-HT_1B in human cortex was traced throughout life, significant changes during adolescence were observed, in a way that is strongly correlated with the expression of 5-HT_1E. Outside of the CNS, the 5-HT_1B receptor is also expressed on the

endothelium The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the ve ...

of blood vessels, particularly in the

meninges In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in th ...

. Activation of these receptors results in

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood ve ...

. The high distribution of vasoconstrictive 5-HT_1B and 5-HT_1D receptors around the brain makes them a valuable drug target for the treatment of migraines. Blocking 5-HT_1B receptor signalling also increases the number of

osteoblast Osteoblasts (from the Greek language, Greek combining forms for "bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cell (biology), cells with a single Cell nucleus, nucleus that synthesize bone. However, in the p ...

s, bone mass, and the bone formation rate. *

Knockout mice A knockout mouse, or knock-out mouse, is a genetically modified mouse (''Mus musculus'') in which researchers have inactivated, or "knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are importan ...

lacking the 5-HT_1B gene have been reported to have a higher preference for alcohol, although later studies failed to replicate such abnormalities in alcohol consumption. These mice have also been reported to have a lower measure of anxiety (such as on the elevated plus maze test) and a higher measure of aggression. Under basal conditions, knockout mice present with a "normal" phenotype and exhibit a sucrose preference (lack of sucrose preference is considered a measure of anhedonia). However, after undergoing chronic unpredictable stress treatment to induce a "depression-like" phenotype these animals do not benefit from administration of

selective serotonin reuptake inhibitor Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions. SSRIs increase the extracellul ...

(SSRIs).

Ligands

Agonists

* Ergotamine (vasoconstrictor in migraine) * Oxymetazoline *

Sumatriptan Sumatriptan, sold commonly under brand names Imitrex and Treximet among others, is a medication used to treat migraine headaches and cluster headaches. It is taken orally, intranasally, or by subcutaneous injection. Therapeutic effects gen ...

(vasoconstrictor in migraine) *

Zolmitriptan Zolmitriptan, sold under the brand name Zomig among others, is a triptan used in the acute treatment of migraine attacks with or without aura and cluster headaches. It is a selective serotonin receptor agonist of the 1B and 1D subtypes. It w ...

* 5-Carboxamidotryptamine * CGS-12066A * CP-93,129 (peripherally acting) * CP-94,253 * CP-122,288 (mixed 5-HT_1B/1D agonist) * CP-135,807 (mixed 5-HT_1B/1D agonist) * RU-24969 (mixed 5-HT_1A/1B agonist)

Partial agonists

* Ziprasidone (

antipsychotic Antipsychotics, also known as neuroleptics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia but also in a range o ...

) * Asenapine (

) *

Vortioxetine Vortioxetine, sold under the brand names Trintellix and Brintellix among others, is a medication used to treat major depressive disorder. Effectiveness is viewed as similar to that of other antidepressants. It is taken by mouth. Common side e ...

( antidepressant)

Antagonists and inverse agonists

Methiothepin Metitepine (; developmental code names Ro 8-6837 ( maleate), VUFB-6276 ( mesylate)), also known as methiothepin, is a drug described as a "psychotropic agent" of the tricyclic group which was never marketed. It acts as a non-selective antagonis ...

(

) * Yohimbine (

aphrodisiac An aphrodisiac is a substance that increases sexual desire, sexual attraction, sexual pleasure, or sexual behavior. Substances range from a variety of plants, spices, foods, and synthetic chemicals. Natural aphrodisiacs like cannabis or coca ...

) * Metergoline * Aripiprazole * Isamoltane * AR-A000002 * SB-216,641 * SB-224,289 (inverse agonist) *

SB-236,057 SB-236057 is a compound which is a potent and binding selectivity, selective inverse agonist for the serotonin Receptor (biochemistry), receptor 5-HT1B receptor, 5-HT1B, acting especially at 5-HT1B autoreceptors on nerve terminals. It produces a ...

(inverse agonist)

Undetermined Action

* Dextromethorphan ( Cough Suppressant)

Genetics

In humans the protein is coded by the gene ''HTR1B''. A genetic variant in the promoter region, '' A-161T'', has been examined with respect to

personality trait In psychology, trait theory (also called dispositional theory) is an approach to the study of human personality. Trait theorists are primarily interested in the measurement of ''traits'', which can be defined as habitual patterns of behaviour, t ...

s and showed no major effect.

References

External links

* * * {{DEFAULTSORT:5-Ht1b Receptor Serotonin receptors Biology of attention deficit hyperactivity disorder