Protein / target
Delta-type opioid receptor
Protein at a glance
Biological role
G protein-coupled enkephalin receptor
Strongest disease association
Alcoholism
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
G protein-coupled receptor that functions as a receptor for endogenous enkephalins and for a subset of other opioids.
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G protein-coupled receptor that functions as a receptor for endogenous enkephalins and for a subset of other opioids. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors, such as adenylate cyclase. Signaling leads to the inhibition of adenylate cyclase activity. Inhibits neurotransmitter release by reducing calcium ion currents and increasing potassium ion conductance. Plays a role in the perception of pain and in opiate-mediated analgesia. Plays a role in developing analgesic tolerance to morphine
Subcellular location
Domains and Gene Ontology detail (29)Hide
Gene Ontology
- Caxon terminus
- Cdendrite membrane
- Cneuron projection
- Cneuronal dense core vesicle
- Cplasma membrane
- Cpostsynaptic density membrane
- Cpresynaptic membrane
- Cspine apparatus
- Csynaptic vesicle membrane
- FG protein-coupled enkephalin receptor activity
- FG protein-coupled opioid receptor activity
- Fneuropeptide binding
Biological roles
What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.
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G protein-coupled signalling
- ·G protein-coupled receptor that functions as a receptor for endogenous enkephalins and f…
- ·G protein-coupled enkephalin receptor activity
- ·G protein-coupled opioid receptor activity
- ·G protein-coupled opioid receptor signaling pathway
Immune signalling
- ·immune response
- ·Interleukin-4 and Interleukin-13 signaling
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Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.
Interaction neighbourhood
Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.
Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.
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.
20 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.
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 OPRD1
Gene-level evidence surfaced through the gene OPRD1 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.
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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
26 compounds recorded · 20 approved · 6 in clinical development
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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.
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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.
- New publicationNaltrexone/bupropion for binge-eating disorder: A randomized, double-blind, placebo-controlled trial.
- New publicationRandomized, proof-of-concept trial of low dose naltrexone for patients with breakthrough symptoms of major depressive disorder on antidepressants.
- New publicationNaltrexone vs Placebo for the Treatment of Alcohol Dependence: A Randomized Clinical Trial.
- New publicationNaltrexone for impulse control disorders in Parkinson disease: a placebo-controlled study.
- New publicationSafety and tolerability of low-dose naltrexone therapy in children with moderate to severe Crohn's disease: a pilot study.
- New publicationGabapentin combined with naltrexone for the treatment of alcohol dependence.
- New publicationLow-dose naltrexone augmentation of nicotine replacement for smoking cessation with reduced weight gain: a randomized trial.
- New publicationAssociation of OPRM1 A118G variant with the relative reinforcing value of nicotine.
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.