Gamma-aminobutyric acid

GABA (also known as gamma-aminobutyric acid) is the brain's primary inhibitory neurotransmitter; it decreases the likelihood that a particular neuron will fire. It works by opening ion channels that allow chloride ions to flood into the neuron.

How do chloride ions make a neuron less likely to fire? Well, remember that most neurons have a resting potential of about -70 mV--that is, the voltage inside the neuron is 70 mV less that the voltage outside the neuron. If that potential changes to about -60 mV or so, the neuron will fire. Now, excitatory neurotransmitters (like acetylcholine) make positive ions flow into the neuron, raising the potential closer to that -60 mV threshold. If chloride ions (which are negative) flow in, the resting potential will move further away from the threshold (say, down to -90 mV). You'll therefore need lots more excitatory neurotransmitter to get the neuron up to -60.

Benzodiazepines (drugs like Valium and Xanax) are GABA agonists.

A common inhibitory neurotransmitter. When released, gamma-amino butyric acid interacts with receptors controlling ion channels which allow an increase in the number of negative ions inside the post synaptic cell.
Overall, the membrane potential of the post synaptic cell is hyper-polarised, and taken further away from its threshold voltage.

Also know as

• 4 amino butanoic acid
• gamma-amino-butanoic acid

Formula: C₄ H₉ N₁ O₂

Along with being a naturally occurring inhibitory neurotransmitter, Gamma-aminobutyric acid is also an over the counter supplement sold to cause relaxation. Although it is somewhat expensive compared to common vitamins, and also somewhat hard to find, it is fairly easy to obtain. In the United States, it is also totally legal, being regulated as a food product, rather than as a drug.

GABA is the basic inhibitory neurotransmitter, and many of the drugs that work on GABA-such as alcohol, benzodiazapenes and barbiturates are fairly heavy substances, legally and pharmacologically speaking. And yet the substance that they are based upon can be acquired easily. And in fact, my unscientific survey of its effects seem to show that it has an effectiveness, as a tranquilizer, somewhere between placebo and a mug of hot cocoa. The best reason for this I have seen cited is the fact that GABA doesn't easily cross the blood/brain barrier: the same reason why a person can't take serotonin as a mood stabilizing chemical. I do admit that the full pharmokinetics are beyond my understanding.

None of this should discourage the person who is seeking a cheap, harmless means of calming anxiety to experiment with GABA. There doesn't seem to be any serious side effects in otherwise healthy individuals, and even though it is comparatively expensive, a month's supply is still cheaper than a single night's supply of alcohol. However, as with all drugs, caution and medical advice is urged.