Dopamine (DA)

Below we have described about the Dopamine (DA) is a neurotransmitter that regulates movement, reward, mood, and plays a role in neurological disorders.

Function of Dopamine (DA):

  • Controls movement, reward, emotion, and endocrine regulation.

Pathways:

  1. Nigrostriatal → movement control (degenerates in Parkinson disease).
  2. Mesolimbic/mesocortical → reward, salience (hyperactive in schizophrenia).
  3. Tuberoinfundibular → tonic inhibition of prolactin release (blocked by antipsychotics → hyperprolactinemia).
  4. Chemoreceptor trigger zone → vomiting reflex (D₂ antagonists are anti‑emetic).

Synthesis Pathway:

  1. Tyrosine (from diet or phenylalanine) → L-DOPA
    • Enzyme: Tyrosine hydroxylase (rate-limiting)
  2. L-DOPADopamine
    • Enzyme: Aromatic L-Amino Acid Decarboxylase (AADC)
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Receptors:

  • D1-like (D1, D5): increase cAMP
  • D2-like (D2, D3, D4): decrease cAMP

Clinical Relevance:

  • Parkinson’s disease (↓ dopamine)
  • Schizophrenia (↑ dopamine in mesolimbic system)
  • Hyperprolactinemia

Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!

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