- Dopamine is a chemical messenger, or neurotransmitter, produced in the brain that plays a key role in regulating mood, motivation, reward, attention, and movement.
- It helps transmit signals between nerve cells and is involved in both physical and emotional responses.
Chemical Structure & Formula
- Chemical Formula: C₈H₁₁NO₂
- Structure:
Advertisements
Mechanism of Action (Detailed)
- Dopamine acts on dopaminergic (D1, D2), α, and β adrenergic receptors in a dose-dependent manner:
-
Low dose (1-3 µg/kg/min):
- Selectively stimulates D1 receptors → Vasodilation in renal, mesenteric, and coronary arteries → Increased renal perfusion & diuresis.
-
Moderate dose (3-10 µg/kg/min):
- Stimulates β1 receptors → Increases heart rate & cardiac contractility.
-
High dose (>10 µg/kg/min):
- Stimulates α1 receptors → Vasoconstriction & increased blood pressure.
Advertisements
Physiological Effects
- Cardiovascular: Dose-dependent vasodilation or vasoconstriction.
- Renal: Increased perfusion & sodium excretion (low doses).
- Metabolic: Minimal metabolic effects compared to epinephrine.
Side Effects of Dopamine
- Tachycardia & Arrhythmias
- Hypertension (at high doses)
- Extravasation injury (if not given through a central line)
Advertisements
Clinical Uses of Dopamine
- Cardiogenic shock – To improve cardiac output.
- Acute heart failure – Inotropic support.
- Septic shock – Used at higher doses to maintain BP.
- Acute renal failure (historically but no longer recommended due to lack of evidence).
Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!
