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.
All of the anticonvulsants routinely used to treat bipolar disorder are blockers of voltage-gated sodium channels, affecting the brain's glutamate system. For valproic acid, carbamazepine and oxcarbazepine, however, their mood-stabilizing effects may be more related to effects on the GABAergic system.