Hyperbaric oxygen decreases the glutamate to GABA ratio by S-nitrosylating glutamic acid decarboxylase, increasing neuronal firing.

“there's two different isozymes and then what we think now is that you have more glutamate to gaba ratio so the enzyme that converts our gamma amino butyric acid have actually created from glutamate right so you have much more excitatory than inhibitory neurotransmitter so that ratio changes and it's a redox dependent reaction actually it's a you have s nitro solution of this enzyme that converts more glutamate to gaba so you have increased neuronal firing and increase release of glutamate and also less conversion of the glutamate to gaba which has a brain stabilizing effect”