Glutamate and GABA: the brain's accelerator and brake
Introduces the main excitatory and inhibitory transmitters — the balance that sedatives, alcohol and withdrawal all tip.
Where this fitsConnects to 1 · Unlocks 1
- Connects to
- Plasticity and neurogenesis — NMDA receptors are how 'fire together, wire together' happens.
- Unlocks
- Therapeutic window, steady state, washout — and tolerance — Stopping a depressant abruptly can cause rebound excitation — a withdrawal risk.
Orient
Amino acid transmitters, widely distributed in the brain: glutamate – major excitatory neurotransmitter; GABA (gamma aminobutyric acid) – major inhibitory neurotransmitter, made from glutamate by GAD. NMDA involved in learning and memory formation – synaptic plasticity. Overactivity at ionotropic glutamate receptors can cause excitotoxicity.
Course terms
Your professor's wording, word for word from the slides. Learn the term and this definition — the explanation underneath is only there to help it make sense.
- Glutamate
“Major excitatory neurotransmitter”Slides 03, p. 32
Receptors: NMDA, kainate, AMPA (ionotropic, excitatory) and mGlu (metabotropic).
- GABA
“Major inhibitory neurotransmitter”Slides 03, p. 32
Gamma aminobutyric acid.
- NMDA receptor
“NMDA involved in learning and memory formation – synaptic plasticity”Slides 03, p. 33
Needs glutamate plus depolarization (to push out magnesium) plus glycine or serine.
- Hebbian learning / LTP
““Neurons that fire together wire together””Slides 03, p. 36
Long-term potentiation: after learning, the postsynaptic neuron adds AMPA receptors.
- Excitotoxicity
“Overactivity at ionotropic glutamate receptors can cause excitotoxicity”Slides 03, p. 37
Excessive Ca²⁺ influx can trigger death of the neuron — after stroke, injury, some drugs, or withdrawal from inhibitory drugs.
- GAD
“Made from glutamate under control of enzyme glutamic acid decarboxylase (GAD)”Slides 03, p. 38
The metabolic link between glutamate and GABA.
- GABA-A receptor
“GABAA target of many “depressant” and sedative drugs”Slides 03, p. 38
GABA-A is ionotropic; GABA-B is metabotropic.
From your course: Course slides 03, pp. 32–39
Tip: the ← and → keys move through the lesson.
Full lesson: Glutamate/NMDA and GABA comparisons