USMLE

D1 (Dopamine) Receptors

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General Pharm
  1. Gs / Gi Pathway
  2. Gq Signaling Pathway
  3. Alpha-1 (Adrenergic) Receptors
  4. Alpha-2 (Adrenergic) Receptors
  5. Beta-1 (Adrenergic) Receptors
  6. Beta-2 (Adrenergic) Receptors
  7. Beta-3 (Adrenergic) Receptors
  8. M1 (Muscarinic) Receptors
  9. M2 (Muscarinic) Receptors
  10. M3 (Muscarinic) Receptors
  11. D1 (Dopamine) Receptors
  12. D2 (Dopamine) Receptors
  13. H1 (Histamine) Receptors
  14. H2 (Histamine) Receptors
  15. V1 (Vasopressin) Receptors
  16. V2 (Vasopressin) Receptors

Summary

D1 receptors are a type of G-protein coupled receptor that activates in response to binding by dopamine. D1 receptors can be found in the brain, but more importantly in the renal vasculature, where their activation induces vasodilation. Therefore D1 receptor signalling can increase renal blood flow, natriuresis and diuresis, thereby lowering blood pressure. D1 receptors utilize a Gs protein subunit as its second messenger in the Gs signaling pathway. Fenoldopam is a selective D1 receptor agonist that is used in hypertensive emergencies to lower blood pressure and preserve renal perfusion.

Key Points

  • D1 Receptors
    • GPCR that binds dopamine
      • Activates a Gs subunit
        • Stimulates adenylyl cyclase and cAMP second messenger cascade
    • Locations
      • Renal, splanchnic, and mesenteric blood vessels
        • Activation induces vasodilation of most arterial beds
    • Actions
      • Increases renal blood flow
        • Via relaxation of renal vascular smooth muscle