htr1b Protein

Serotonin Receptor 1B Protein

Introduction

Htr1B Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-protein"> [@barnes1988]

| Attribute | Value | [@goa1996]
|-----------|-------| [@sari2004]
| Protein Name | Serotonin Receptor 1B | [@saudou1994]
| Gene Symbol | [htr1b](/proteins/htr1b-protein) |
| UniProt ID | [P28222](https://www.uniprot.org/uniprot/P28222) |
| Molecular Weight | ~43-50 kDa |
| Subcellular Localization | Plasma membrane, presynaptic terminals |
| Protein Family | 5-HT1 family (GPCR) |
| Signal Transduction | Gi/o protein-coupled, inhibits adenylate cyclase |

</div>}

Overview

The Serotonin Receptor 1B (HTR1B) is a G protein-coupled receptor encoded by the [HTR1B](/proteins/htr1b-protein) gene. It functions as both an autoreceptor (regulating serotonin release) and heteroreceptor (modulating release of other neurotransmitters). HTR1B is a key target for migraine medications, antidepressants, and drugs for substance abuse.

Structure

HTR1B exhibits the classic seven-transmembrane GPCR architecture:

• N-terminal extracellular domain: Contains glycosylation sites
• Transmembrane helices (TM1-TM7): Form the ligand-binding pocket
• Cysteine-rich disulfide bond: Between ECL1 and ECL2 for structural stability
• Differential splicing: Generates multiple receptor isoforms

...

Serotonin Receptor 1B Protein

Introduction

Htr1B Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-protein"> [@barnes1988]

| Attribute | Value | [@goa1996]
|-----------|-------| [@sari2004]
| Protein Name | Serotonin Receptor 1B | [@saudou1994]
| Gene Symbol | [htr1b](/proteins/htr1b-protein) |
| UniProt ID | [P28222](https://www.uniprot.org/uniprot/P28222) |
| Molecular Weight | ~43-50 kDa |
| Subcellular Localization | Plasma membrane, presynaptic terminals |
| Protein Family | 5-HT1 family (GPCR) |
| Signal Transduction | Gi/o protein-coupled, inhibits adenylate cyclase |

</div>}

Overview

The Serotonin Receptor 1B (HTR1B) is a G protein-coupled receptor encoded by the [HTR1B](/proteins/htr1b-protein) gene. It functions as both an autoreceptor (regulating serotonin release) and heteroreceptor (modulating release of other neurotransmitters). HTR1B is a key target for migraine medications, antidepressants, and drugs for substance abuse.

Structure

HTR1B exhibits the classic seven-transmembrane GPCR architecture:

• N-terminal extracellular domain: Contains glycosylation sites
• Transmembrane helices (TM1-TM7): Form the ligand-binding pocket
• Cysteine-rich disulfide bond: Between ECL1 and ECL2 for structural stability
• Differential splicing: Generates multiple receptor isoforms

The receptor has high affinity for serotonin (5-HT) and is sensitive to tryptamine derivatives.

Normal Function

HTR1B serves critical regulatory functions:

• Presynaptic autoreceptor: Located on serotonin neuron terminals, inhibits further 5-HT release
• Presynaptic heteroreceptor: Modulates glutamate, GABA, and dopamine release
• Migraine pathophysiology: Trigeminovascular activation involves HTR1B
• Aggression and mood: Prefrontal [cortex](/brain-regions/cortex) expression affects aggressive behavior
• Reward and addiction: Modulates dopaminergic reward pathways

Role in Neurodegeneration

Migraine

HTR1B is the primary target for triptans (sumatriptan, zolmitriptan, rizatriptan), which are acute migraine abortives. These drugs act as HTR1B (and HTR1D) agonists to cause cranial vasoconstriction and inhibit trigeminal nociception.

Parkinson's Disease

HTR1B alterations affect serotonin-dopamine interactions in basal ganglia. Altered receptor density has been reported in PD brains, contributing to non-motor symptoms including depression and anxiety.

Alzheimer's Disease

HTR1B signaling modulates [amyloid precursor protein](/entities/app-protein) processing. Animal studies suggest HTR1B agonists may reduce [Aβ](/proteins/amyloid-beta) production, though human data are limited.

Depression and Anxiety

HTR1B is implicated in mood disorders through its role in serotonin autoreceptor function. Chronic SSRI treatment leads to HTR1B desensitization, enhancing antidepressant efficacy.

Therapeutic Targeting

| Drug Class | Examples | Mechanism | Status |
|-----------|----------|-----------|--------|
| Triptans | Sumatriptan, Zolmitriptan | HTR1B/1D agonists | FDA approved for migraine |
| Antidepressants | SSRIs (indirect) | Downregulate HTR1B | FDA approved |
| Research Compounds | CP-93,129, Isohexenyl | Selective agonists/antagonists | Preclinical |

Research Directions

• Novel 5-HT1B-selective agonists with better cardiovascular safety
• HTR1B antagonists for antidepressant augmentation
• PET ligands for studying receptor occupancy in vivo

Background

The study of Htr1B Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

See Also

• HTR1B Gene
• [Serotonin Receptors](/mechanisms/serotonergic-signaling)
• [Migraine](/diseases/migraine)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Depression](/diseases/depression)

External Links

• [UniProt: HTR1B](https://www.uniprot.org/uniprot/P28222)
• [IUPHAR: HTR1B](https://www.guidetopharmacology.org/GRAC/ReceptorDisplayForward?receptorID=2)

References

[Hoyer D, et al, (1985) (1985)](https://pubmed.ncbi.nlm.nih.gov/2995204/)

[Barnes NM, et al, (1988) (1988)](https://pubmed.ncbi.nlm.nih.gov/2907428/)

[Goa K, et al, (1996) (1996)](https://pubmed.ncbi.nlm.nih.gov/8785319/)

[Sari Y, et al, (2004) (2004)](https://pubmed.ncbi.nlm.nih.gov/15026168/)

[Saudou F, et al, (1994) (1994)](https://pubmed.ncbi.nlm.nih.gov/8235615/)