Gamma-Aminobutyric acid (GABA)

=== Unfinished ===

Need to consolidate and re-organise some of the stuff from [Neuromuscular junction], [Acetylcholine] and [Receptors]

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[WG21:p111]

Gamma-aminobutyric acid (GABA) is the major inhibitory mediator in the brain
--> Neurotransmitter at 20% of the CNS synapses

Also present in retina
--> Responsible for presynaptic inhibition

Glutamate undergoes decarboxylation to form GABA
* Catalysed by glutamate decarboxylase (GAD)

GABA is metabolised (deamination) into succinic semialdehyde
* Catalysed by GABA transaminase

Succinic semialdehyde is later transformed to succinate in the citric acid cycle

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[RD5:p470]

GABA is the main inhibitory transmitter in the brain.

In spinal cord and brainstem, glycine is also an important inhibitory transmitter

Glutamate decarboxylase is an enzyme found only in the GABA-synthesising neurons in t he brain

GABA is take up by GABA-ergic neurons and astrocytes via specific transporter
--> This reuptake is the primary mechanism for GABA removal
* Breakdown (deamination) of GABA is supplementary

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[SH4:p21]

GABA is the major inhibitory neurotransmitter for the brain

GABA is responsible for most fast synaptic inhibition of neurons

Approximately 1/3 of all synapses in the CNS are responsive to GABA

GABA is not pharmacologically active when administered systemically because it cannot cross the BBB