|MadSci Network: Medicine|
Sodium Amytal (sodium amobarbital) is a fast-acting barbituate anesthetic. Like all barbituates, its main way of acting in the brain is to increase the inhibition in the brain by increasing GABAergic inhibition. GABA (gamma-aminobuteric acid) is the main inhibitory neurotransmitter used by the brain. Inhibition turns off neurons (brain cells). If you turn off too many neurons, you lose consciousness. In addition, when one has been exposed to sodium Amytal (but less than what causes one to lose consciousness), alcohol and some other drugs, one loses inhibition. This means one would do things that one would not normally do. My favorite use of sodium Amytal is in what is called the sodium Amytal test or Wadda test. (Actually, I have never seen this test in person. But I like the theory.) In this test, an IV is started in the carotid artery (Warning: Any manipulation of the carotid artery is very dangerous; Do NOT do this at home or school). The left and right carotid arteries are the main arterie that supply the brain with blood. Sodium Amytal is injected into the artery, and whichever side of the brain is controled by that artery falls asleep. If the person's lanuqage is controlled by his left side of his brain (most people are this way) and the sodium Amytal is injected into the left carotid artery, the person stops talking. If the Amytal is injected into the right side, he continues talking. These days, there are better tests for this sort of thing, like PET scans and fMRI scans, so it is rarely done.
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