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.
Although GABA activity doesn't entirely explain alcohol's effects and we don't know exactly what the delta receptor does, a big part of the mystery seems to have come unraveled. Because GABA is the primary inhibitory neuron in the brain, it can affect virtually every system. Alcohol is more than simply a depressant. The physical structure of the brain remains constant, but the addition of a tiny chemical drastically alters brain function and ultimately behavior. Understanding how alcohol affects our brain also offers insight into how our brains work in general. So the next time you drink, even though you may be killing some valuable brain cells, you can toast to the fact that you're contributing to neuroscience. Notes: Giancola PR, Zeichner A. The biphasic effects of alcohol on human physical aggression. J Abnorm Psychol. 1997 Nov;106(4):598-607. McDougle CJ, Krystal JH, Price LH, Heninger GR, Charney DS.