It’s Five O’clock Somewhere
And even if it wasn’t it probably wouldn’t stop many people from drinking. Alcohol abuse and dependence are global health issues and in the United States they affect about 14 million people. The article we read on the ethanol (alcohol) also describes that there are few choices for treatment alcohol use disorders. One reason for this is likely that the action of alcohol on the brain is not well understood. However, the article seeks to offer some possible mechanisms for the interesting ways alcohol changes cognition and behavior.
Is This an Off Switch or Not?
Alcohol has an interesting way of inhibiting particular parts of the brain, while activating others. Ethanol increases the firing rate of dopamine neurons, which play an important role in the reward pathway in the brain, yet it inhibits other neural elements known as NMDA receptors, which are another important actor in ethanol’s rewarding effects in the brain. How can this be? Interestingly, the extra dopamine firing leads to an inactivation of a molecule, called pp-1, that usually helps to shut off NMDA receptors after they’ve been activated. In other words, even though NMDA receptors have decreased action when affected by ethanol, they also have increased action because they aren’t being turned off by pp-1. It turns out that during this interaction the effect of inactivated pp-1 is larger than ethanol. Meaning that NMDA receptors aren’t inhibited much by ethanol despite its direct effect on the receptors. This is exhibited by mice that are lacking a crucial element in the pathway to inactivate pp-1, known as DARPP-32, show less ethanol self-administration than mice with DARPP-32. This is evidence that increased dopamine and NMDA receptor activity are likely important to alcohol dependence in humans as well.
Ethanol’s Big Effects – Perhaps Due to Tiny Interactions
The other interesting effect of ethanol I’m going to talk about is its incorporation into the cells of the body. An enzyme known as PLD is important to the incorporation of ethanol into the body cells. Normally this enzyme acts to produce a molecule, phosphatidic acid, which acts to relay signals to important cellular proteins. However, in the presence of ethanol, PLD would much rather hang out with ethanol and convert it into PEth so that it fits into cell membranes, which are barriers around the cells that act to keep out certain materials and letting in other. When PEth is incorporated into cell membranes it increase the rate at which ethanol can enter the cell and prevents phosphatidic acid from relaying its signal to the proteins within the cell. Both of these actions act to change cellular function and it is suggested that one of the two or both may lead to increased alcohol tolerance. Unfortunately, both alcohol tolerance and alcohol dependence have very limited options for pharmacological treatment. As usual, the best way to solve this problem is continued research and discussion. Every new discovery leads to possible solutions to issues facing many people locally and abroad.
Alcohol – Inhibition to the Point of Activity
