Prevalence of vitamin A deficiency. Vitamin A deficiency (VAD) is a lack of vitamin A in humans. It is common in poorer countries but rarely seen in more developed countries. Nyctalopia (night blindness) is one of the first signs of VAD.revalence of vitamin A deficiency. Vitamin A deficiency (VAD) is a lack of vitamin A in humans. It is common in poorer countries but rarely seen in more developed countries. Nyctalopia (night blindness) is one of the first signs of VAD.
Both lithium and valproate have been reported to increase rat CSF GABA levels. Regarding valproate, animal studies reported that it enhances GABA levels, GABA synaptic release, GAD activity, neuronal GABA responsiveness, and inhibits GABA-T in several brain regions.
Report Abuse. GABA (gamma-aminobutyric acid) is an amino acid that functions as a neurotransmitter in the brain. GABA is synthesized in the brain from another amino acid, glutamate, and functions as an inhibitory neurotransmitter â meaning that it blocks nerve impulses.ABA is synthesized in the brain from another amino acid, glutamate, and functions as an inhibitory neurotransmitter â meaning that it blocks nerve impulses.