Wednesday, December 6, 2006
Neuropharmacology of alcohol: One reason why you don't want to become an alcoholic
The active ingredient of alcohol is as most people already know, ethanol. We all know too well what the behavioral effects of this drug is, people who were previously shy starts to dance on tables, we say things we later regret, people hook up or break up, or worse, get into fights. In sum we lose our inhibitions and become reptiles for an evening. How do these effects arise?
Before I had taken a course in pharmacology I thought it would be almost as dull as economics (I have not studied economics, so this is just a prejudice of mine). I do not know if it was because of our terrific teacher, Karen Szumlinski (UCSB), nevertheless, I now consider pharmacology, and particularly neuropharmacology as one of the most interesting subjects there is. Anyways, back to the subject. Alcohol affects many different transmitter systems in our brain, amongst them the GABA system and the Glutamate system. The GABA system mainly inhibits our brain, so when alcohol comes and stimulates the GABA system it means that certain brain regions will become more inhibited. Most notably, our frontal cortex is inhibited. (I am sorry if this gets too technical.) The frontal lobe inhibits impulses, so when alcohol comes and stimulates the GABA system, this inhibits the frontal lobe, which in turn prevents us from inhibiting impulses, thus you get dancing on the tables. At a larger dose the GABAa system will become so active that you lose your conscience (see picture).
Another, potentially more dangerous, effect of alcohol is its effect on the glutamate system and the NMDA receptor. Activating these receptors will activate the neuron and make it fire, if you overactive the NMDA receptor, the cell will become hyperactive and die. Alcohol is actually an NMDA antagonist meaning that it prevents activity at this receptor, however, when you are on your third bottle of wine and the brain realizes that there is no activity at any of the NMDA receptors anymore it gets worried. It has a solution to this however: Make more NMDA receptors! If you are an alcoholic and drink a lot, often, then your brain will produce tons of receptors. When you finally put down the bottle for a while, there will be excess NMDA activity and many cells will die. In sum then, drinking alcohol will cause an up regulation of NMDA receptors which in turn will cause excess activity at these receptors when there is no antagonist (such as alcohol) present.
Also, one last advice, don't drink coffee the day after, it can cause seizures...