Neurotransmitter Receptors

There are different types of receptors:

  • Ionotropic receptors: protein complexes that direct the coupling of the neurotransmitter receptor to an ion channel.
  • Metabotropic receptors: when activated, leads to the activation of a secondary mechanism inside the cell.
    • Most common are G-protein-couple receptors (GPCRs)
      • There are over 2 000 GPCR genes in the human genome (~10% of all genes)
      • Transmembrane protein complex
      • Alpha, beta and gamma proteins (g-proteins) due to GTP
      • Versatile

Glutamate Receptors

Glutamate is the main excitatory neurotransmitter of the central nervous system. Used in more than 90% of a human brain’s synaptic connections.

There are two different ionotropic glutamate receptors:

  • AMPA: fast excitatory postsynaptic receptors; promiscuous, i.e., permeable to all cations; ligand.
  • NMDA: LTP; binds to NMDA receptors; used inn the learning and memory functions of the brain (synaptic plasticity); ligand and voltage-gated; they need AMPA receptors to open up.
    • LTP
    • Let’s Cations pass through it (calcium mostly)
    • when at rest, receives mg+
    • when depolarized, repels mg+
    • AMPA open NMDA membranes

Glycine Receptors

  • Ionotropic.
  • Strychnine is a powerful antagonist of the glycine receptor.