Dopamine Receptor D2 (Drd2) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
This page provides comprehensive information about Dopamine Receptor D2, including its structure, normal function in the nervous system, and its role in neurodegenerative diseases.
:: infobox infobox-protein
!Protein Name | Dopamine Receptor D2 (DRD2)
!Gene | DRD2
!UniProt ID | P14416
!PDB Structure | 6CM4, 7R0H, 7VAB
!Molecular Weight | ~51 kDa (GPCR)
!Subcellular Localization | Cell membrane (GPCR), presynaptic terminals
!Protein Family | Dopamine receptor family (D2-like), GPCR class A
!
DRD2 exists in two primary splice variants:
- DRD2S (short): 414 amino acids, mainly presynaptic
- DRD2L (long): 443 amino acids, mainly postsynaptic
Domain Organization:
- N-terminal extracellular domain (aa 1-46): Glycosylated extracellular loops
- Seven transmembrane helices (TM1-TM7): Classic GPCR structure
- Third intracellular loop (aa 156-211): Couples to Gi/o proteins (long isoform)
- C-terminal tail (aa 371-443): Contains cysteine for palmitoylation and membrane anchoring
The D2 receptor has higher affinity for dopamine than D1, allowing distinct signaling at lower dopamine concentrations.
DRD2 mediates inhibitory dopamine signaling:
- G-protein Coupling: Couples to Gi/o proteins, inhibiting adenylyl cyclase and reducing cAMP
- Presynaptic Autoreceptor: Regulates dopamine synthesis, release, and neuronal firing
- Motor Control: Inhibits the indirect pathway in basal ganglia
- Reward Modulation: Mediates aversive aspects of dopamine signaling
- Prolactin Regulation: Inhibits prolactin release from the pituitary
- Therapeutic Target: D2/D3 agonists (pramipexole, ropinirole, rotigotine) are first-line treatments
- Motor Symptoms: D2 activation improves bradykinesia and rigidity
- Motor Complications: Long-term use associated with dyskinesias and motor fluctuations
- D2 Blockade: Classic antipsychotics (haloperidol, risperidone) primarily block D2 receptors
- Positive Symptoms: D2 antagonism reduces hallucinations and delusions
- EPS: D2 blockade in striatum causes extrapyramidal side effects
- Atypical Antipsychotics: Lower D2 affinity, also target 5-HT2 receptors
- D2 Receptor Loss: Progressive decline in D2 receptor binding in striatum
- Motor Symptoms: Contributes to chorea and dystonia
- D2 Agonists: Bromocriptine, cabergoline used to treat prolactin-secreting pituitary adenomas
| Drug Class |
Examples |
Primary Target |
| D2 Agonists |
Pramipexole, Ropinirole |
D2/D3 |
| D2 Partial Agonists |
Aripiprazole |
D2, 5-HT1A |
| Typical Antipsychotics |
Haloperidol, Chlorpromazine |
D2 |
| Atypical Antipsychotics |
Risperidone, Clozapine |
D2, 5-HT2 |
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Beaulieu JM, Gainetdinov RR. (2011) "The physiology, signaling, and pharmacology of dopamine receptors." Pharmacol Rev 63:182-217. DOI:10.1124/pr.110.002642
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Mailman R, et al. (2000) "Functional effects of dopamine receptor agonists." Adv Pharmacol 47:53-87.
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Strange PG. (2008) "Signaling mechanisms of D2 dopamine receptors." Adv Pharmacol 55:37-52.
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Seeman P. (2013) "Schizophrenia and dopamine receptors." Eur Neuropsychopharmacol 23:999-1009.
The study of Dopamine Receptor D2 (Drd2) 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.
- [1], [2], [3], [4] (See Key Publications for full citations)
- Beaulieu JM, et al. (2011). Dopamine D2 receptor signaling. Pharmacol Rev. PMID:21873469
- Missale C, et al. (1998). D2 receptor isoforms. Physiol Rev. PMID:9720590
- Girault JA, et al. (2007). D2 receptors in basal ganglia. Nat Rev Neurosci. PMID:17559332
- Seeman P. (2007). Dopamine D2 receptors. Am J Psychiatry. PMID:17606634
- Vallone D, et al. (2002). D2 receptors and behavior. Neurosci Biobehav Rev. PMID:11856549