Lecture 2: Glutamate & GABA: Alcohol, Ketamine - Psychosis & Epilepsy

What was the furst neurotransmitter to evolve?

• glutamate & GABA

• Found in primitive organisms i.e. hydra or flatworms

What are true neurotransmitters

• glutamate & GABA

• Directly affect likelihood of post-synaptic firing

What effect does glutamate have on post-synaptic neuron?

• Main excitary neurotransmitter in brain

  • Increase likelihood of firing

What neurons release glutamate + what do their projects look like?

• all excitatory cells (80% cerbral cortex - glutamatergic pyramidal cells)

• long projections

What is the other name for glutamate?

glutamic acid (amino acid)

• same exxact thingg

How does the brain synthesise glutamate

• Cannot cross blood brain barier - synthesises in brain from glutamine released by glial cells neighbouring neurons

  • By glutaminase enzyme (one step) + packaged in vesicles by vesicle glutamate transporters

• Glutamine is the inactive form - made in glial + transported in pre-synaptic

  • Enzymes convert in terminal to glutamate

  • Process allows glutamate to be cleamed up + interconverted to glutamine - to prevent constant stimulation (which would lead to seizures) via glutamine synthase enzyme

What is the problem of excess glutamate?

• (which would lead to seizures) via glutamine synthase enzyme

  • Excess glu can cause exictotoxicity leading to neuron damage (e.g. in stroke)