by Biologist » Tue Aug 21, 2007 9:54 pm
Interesting post, bucho. Good questions.
I read this recently and found it online about addiction just now. Whether it is worth reading or not, I don't know. The interesting parts to me are included below. My guess is that statins have caused a change in the receptors of "the pleasure centers" and that it may not be permanent, while long lasting. In the case of the author, apparently after many years, there has been a change in his brain away from addiction -- but the article is too much "behavior oriented" to be real applicable to statin users' issues -- even though the changes -- in both directions -- are probably reflected in brain physiology or chemistry. While unlikely, it is possible that we now manufacture more alcohol dehydrogenase which simply takes apart the alcohol before it hits the blood stream. Not likely, but as you will read below, it is possible:
*http://www.time.com/time/magazine/article/0,9171,1640436-1,00.html
"Another area of focus for researchers involves the brain's reward system, powered largely by the neurotransmitter dopamine. Investigators are looking specifically at the family of dopamine receptors that populate nerve cells and bind to the compound. The hope is that if you can dampen the effect of the brain chemical that carries the pleasurable signal, you can loosen the drug's hold.
One particular group of dopamine receptors, for example, called D3, seems to multiply in the presence of cocaine, methamphetamine and nicotine, making it possible for more of the drug to enter and activate nerve cells. "Receptor density is thought to be an amplifier," says Frank Vocci, director of pharmacotherapies at NIDA. "[Chemically] blocking D3 interrupts an awful lot of the drugs' effects. It is probably the hottest target in modulating the reward system."
But just as there are two ways to stop a speeding car--by easing off the gas or hitting the brake pedal--there are two different possibilities for muting addiction. If dopamine receptors are the gas, the brain's own inhibitory systems act as the brakes. In addicts, this natural damping circuit, called GABA (gamma-aminobutyric acid), appears to be faulty. Without a proper chemical check on excitatory messages set off by drugs, the brain never appreciates that it's been satiated.
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That led researchers to wonder about other biological differences in the way men and women become addicted and, significantly, respond to treatments. Alcohol dependence is one very promising area. For years, researchers had documented the way female alcoholics tend to progress more rapidly to alcoholism than men. This telescoping effect, they now know, has a lot to do with the way women metabolize alcohol. Females are endowed with less alcohol dehydrogenase--the first enzyme in the stomach lining that starts to break down the ethanol in liquor--and less total body water than men. Together with estrogen, these factors have a net concentrating effect on the alcohol in the blood, giving women a more intense hit with each drink. The pleasure from that extreme high may be enough for some women to feel satisfied and therefore drink less. For others, the intense intoxication is so enjoyable that they try to duplicate the experience over and over.
But it's the brain, not the gut, that continues to get most of the attention, and one of the biggest reasons is technology. It was in 1985 that Volkow first began using PET scans to record trademark characteristics in the brains and nerve cells of chronic drug abusers, including blood flow, dopamine levels and glucose metabolism--a measure of how much energy is being used and where (and therefore a stand-in for figuring out which cells are at work). After the subjects had been abstinent a year, Volkow rescanned their brains and found that they had begun to return to their predrug state. Good news, certainly, but only as far as it goes.
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While such relearning has not been studied formally in humans, Vocci believes it will work, on the basis of studies involving, of all things, phobias. It turns out that phobias and drugs exploit the same struggle between high and low circuits in the brain. People placed in a virtual-reality glass elevator and treated with the antibiotic D-cycloserine were better able to overcome their fear of heights than those without benefit of the drug. Says Vocci: "I never thought we would have drugs that affect cognition in such a specific way."