NMDA receptor

• Mechanism
  • Ligand-gated AND Voltage-gated.
  • Requires Glutamate + Glycine (co-agonist).
  • Depolarization removes the Mg2+ plug blocking the pore.
  • Result: Ca2+ influx (critical for signaling).
• Physiology
  • Long-Term Potentiation (LTP): Basis for learning/memory.
• Pathology
  • Excitotoxicity: Excess Ca2+ influx $\to$ neuronal death (e.g., Ischemic Stroke, Huntington Disease).
• Pharmacology (NMDA Antagonists)
  • Memantine: Alzheimer’s disease (neuroprotective).
  • Ketamine: Dissociative anesthetic.
  • PCP: Hallucinogen (violence, nystagmus).
  • Amantadine: Parkinson’s disease.
  • Dextromethorphan: Antitussive (abuse potential).