Protein / target
5-hydroxytryptamine receptor 3A
Protein at a glance
Biological role
Serotonin-gated monoatomic cation channel
Strongest disease association
Major depressive disorder
Therapeutic position
Established drug target
Derived from structured UniProt, Open Targets and literature data on this page.
Protein profile
Canonical identity and biological annotation from UniProt.
Function overview
Forms serotonin (5-hydroxytryptamine/5-HT3)-activated cation-selective channel complexes, which when activated cause fast, depolarizing responses in neurons
Subcellular location
Domains and Gene Ontology detail (18)Hide
Gene Ontology
- Ccleavage furrow
- Cneuron projection
- Cplasma membrane
- Cpostsynaptic membrane
- Cserotonin-activated cation-selective channel complex
- Csynapse
- Ctransmembrane transporter complex
- Fexcitatory extracellular ligand-gated monoatomic ion channel activity
- Fidentical protein binding
- Fligand-gated monoatomic ion channel activity involved in regulation of presynaptic membrane potential
- Fserotonin binding
- Fserotonin-gated monoatomic cation channel activity
Biological roles
What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.
View supporting evidenceHide supporting evidence
Synaptic signalling
- ·Postsynaptic cell membrane
- ·postsynaptic membrane
- ·synapse
- ·ligand-gated monoatomic ion channel activity involved in regulation of presynaptic membr…
Ion channel gating
- ·excitatory extracellular ligand-gated monoatomic ion channel activity
- ·ligand-gated monoatomic ion channel activity involved in regulation of presynaptic membr…
- ·serotonin-gated monoatomic cation channel activity
- ·transmitter-gated monoatomic ion channel activity involved in regulation of postsynaptic…
Ligand-gated signalling
- ·excitatory extracellular ligand-gated monoatomic ion channel activity
- ·ligand-gated monoatomic ion channel activity involved in regulation of presynaptic membr…
- ·transmitter-gated monoatomic ion channel activity involved in regulation of postsynaptic…
Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.
Approved medicines with mapped indications
Approved therapies targeting this protein, grouped by what they are approved to treat — the disease-first view of the medicines below. Relationships come from the canonical approved-indication graph (ChEMBL phase-4), the same source as the drug cards.
Broader indication categories (1)Hide
Broad umbrella indications (e.g. “Neoplasms”). Shown here because every medicine also appears under a more specific disease above — kept for completeness, de-emphasised for clarity.
23 medicines meet Open Targets' target-level approved-medicine definition; the 1 shown here are those on this page with a canonical approved disease indication in the graph. Approved indications from ChEMBL (phase-4), via the canonical drug→disease graph.
Drugs targeting this protein
How approved and investigational drugs engage this protein — mechanism and action type, direct vs complex targeting, and how broadly each acts across other targets. A drug-first view (the section above groups the approved ones disease-first); direct binders with few recorded targets are listed first.
Serotonin 3a (5-HT3a) receptor antagonist
Indicated for Nausea, Postoperative Nausea and Vomiting, Neoplasms
ChEMBL mechanism, action type, target identity and approved indications. Open Targets clinical status.
Translational evidence
Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.
Strongest disease associations · via encoding gene HTR3A
Gene-level evidence surfaced through the gene HTR3A that encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.
View evidence synthesis (5)Hide
The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.
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Drug development
29 compounds recorded · 23 approved · 4 in clinical development · 2 earlier-stage
View all recorded compounds (10)Hide
Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.
Tractability
Small molecules — Strong
Antibodies — Emerging
Protein degraders — Emerging
View underlying tractability evidence (9)Hide
Raw Open Targets tractability assessment buckets, by modality.
Safety-related annotations
Terms indexed against this target in Open Targets' safety data, with their datasource. These are annotations, not causal claims: the direction of effect (whether activation or inhibition is implicated), species and evidence strength are not captured here, so an entry does not mean that modulating this target is known to cause that condition.
Clinical trials
Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein. Ranked by active status, then clinical phase and recency, and spread across the targeting drugs.
View all trials (26)Hide
ClinicalTrials.gov via the drug-target graph.
What's happening now
Recent therapeutic activity around this target — regulatory actions, clinical trials and safety signals for a drug that targets this protein, plus publications where such a drug is a genuine subject. Every item is reached indirectly through the drug, not the protein itself; incidental mentions (a paper that merely measures a drug) and press items are excluded.
- Product recall
Recall (Class II): ONDANSETRON
- Safety communication
Drug Safety Update: Ondansetron: small increased risk of oral clefts following use in the first 12 weeks of pregnancy
- New publicationAcute opioid withdrawal is associated with increased neural activity in reward-processing centers in healthy men: A functional magnetic resonance imaging study.
- Safety communication
Drug Safety Update: Ondansetron (Zofran): important new intravenous dose restriction
- New publicationOndansetron pharmacokinetics in pregnant women and neonates: towards a new treatment for neonatal abstinence syndrome.
Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.