GABA
Glutamate and Aspartate

γ-Aminobutyric acid (GABA) is the chief inhibitory neurotransmitter in the mammalian central nervous system. It plays a role in regulating neuronal excitability throughout the nervous system and in humans is also directly responsible for the regulation of muscle tone (relaxation).

Metabolic pathways of GABA.

• Acquisition of substrate for GABA synthesis
• GABA synthesis
• GABA packaging into synaptic vesicles
• breakdown of GABA by respective proteins

Acquisition of substrate for GABA synthesis

• GAT1 (GABA)
• EEAT3 (GLU)
• SNAT 1/2 (GLN from glia via SNAT 3/5)

GABA synthesis

GLN --> GLU

• Glutaminase (GS1)

GLU --> GABA

Glutamate_decarboxylase -GAD

Inhibition of mitochondrial oxidative phosphorylation induces hyper-expression of glutamic acid decarboxylase in pancreatic islet cells. 1999

GABA and Vitamin B6

GABA packaging into synaptic vesicles

• vGAT

breakdown of GABA by respective proteins

GABA and Glycine figure

GABA and Glycine text

GABA in C Elegans

GABA Receptors Agonists

Differences in cardiovascular responses to peripherally administered GABA as influenced by basal conditions and type of anaesthesia, 1986

Various GABAA receptor agonists (homotaurine, muscimol, THIP, 5-aminovaleric acid) mimicked the 'excitatory' effect of GABA in reserpine pretreated animals anaesthetized with barbitone and prevented the effects of subsequent GABA administration. On the other hand (±)- baclofen, a selective GABAB receptor agonist, had a slight depressant effect and did not prevent the 'excitatory' cardiovascular effects of GABA.

Agonists of GABA receptor B

Baclofen

Baclofen, sold under the brand name Lioresal among others, is a medication used to treat muscle spasticity such as from a spinal cord injury or multiple sclerosis.[It may also be used for hiccups and muscle spasms near the end of life, and off-label to treat alcohol use disorder or opioid withdrawal symptoms