Alpha-2 (Adrenergic) Receptors
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General Pharm
- Gs / Gi Pathway
- Gq Signaling Pathway
- Alpha-1 (Adrenergic) Receptors
- Alpha-2 (Adrenergic) Receptors
- Beta-1 (Adrenergic) Receptors
- Beta-2 (Adrenergic) Receptors
- Beta-3 (Adrenergic) Receptors
- M1 (Muscarinic) Receptors
- M2 (Muscarinic) Receptors
- M3 (Muscarinic) Receptors
- D1 (Dopamine) Receptors
- D2 (Dopamine) Receptors
- H1 (Histamine) Receptors
- H2 (Histamine) Receptors
- V1 (Vasopressin) Receptors
- V2 (Vasopressin) Receptors
Summary
Alpha-2 receptors are adrenergic receptors, meaning that they bind norepinephrine and epinephrine. Binding causes the activation of a Gi protein subunit, which inhibit adenylate cyclase, decreasing cAMP. This will lead to a number of clinical effects, including decreased sympathetic outflow, decreased insulin release, and decreased aqueous humor production. Alpha-2 receptor agonists use these effects to treat hypertension, ADHD, and glaucoma.
Key Points
- Alpha-2 Receptors
- Signaling
- Use the Gi signaling pathway
- → decreased cAMP
- Use the Gi signaling pathway
- Outcomes
- Decreased sympathetic outflow
- Decreased insulin release
- Via alpha-2 on pancreas
- Beta-2 increases insulin release, but alpha-2 is normally predominant (so sympathetic stimulation inhibits insulin secretion)
- Via alpha-2 on pancreas
- Decreased aqueous humor production
- Increased platelet aggregation (lower yield)
- Decreased lipolysis (lower yield)
- Signaling