GABA shunt

GABA is formed in vivo by a metabolic pathway referred to as the GABA shunt 291... 

Figure 6.3. GABA shunt as an alternative to a-ketoglutarate dehydrogenase in the citric acid cycle. 2-Oxoglutarate dehydrogenase, EC 1.2.4.2 glutamate decarboxylase, EC 4.1.1.15 GABA aminotransferase, EC 2.6.1.19 and succinic semialdehyde dehydrogenase, ECl.2.1.16.

As noted in Section 6.3.1.3, brain GABA falls in thiamin deficiency, but there is increased flux through the GABA shunt. The changes in the cerebellum occur early, and asymptomatic animals are more sensitive than normal to the GABA antagonist picrotoxin. Brain concentrations of glutamate and aspartate are also reduced in thiamin deficiency, as are several other neurotransmitters. 

The irreversible hrain lesions tire associated with decreased acdvity of 2-oxogluteirate dehydrogeneise emd increeised activity of the GABA shunt (Section... 

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