By: By Tanya Lewis, Staff Writer
Published: 10/13/2013 02:09 PM EDT on LiveScience
Boosting levels of a naturally occurring compound in the brain could prevent people who abuse marijuana but are trying to quit from relapsing, a new study suggests.
Researchers studying drug-addicted rats and monkeys found that a substance called kynurenic acid blunted the rewarding effects of THC, the active ingredient in marijuana. Kynurenic acid works by blocking the receptors that increase the flood of good feelings brought on by the brain chemical dopamine.
"Any drug of abuse has to do with dopamine," said study researcher Robert Schwarcz, a professor of psychiatry at the University of Maryland, in College Park. "We found out few years ago that kynurenic acid controls dopamine. All we had to do was put those things together," Schwarcz said.
More people seek treatment for marijuana use in the United States than for cocaine or heroin use, surveys show. Yet there are no medications approved for treating marijuana addiction. [5 Bad Habits You Should Still Quit]
The THC in marijuana activates dopamine neurons in a brain region called the ventral tegmental area (VTA), causing the cells to release the feel-good chemical from nerves in the nucleus accumbens. Previous attempts to find a treatment for marijuana addiction showed that blocking receptors in the VTA and the nucleus accumbens prevented the surge in dopamine, but those treatments caused side effects.
The researchers speculated that kynurenic acid — which is produced by the breakdown of a chemical found in bananas and turkey, called tryptophan — may have fewer side effects, because it naturally controls dopamine levels in the brain.
To find out whether kynurenic acid could treat marijuana dependence, Schwarcz's colleagues gave rats and squirrel monkeys a drug that boosted their levels of kynurenic acid, while the animals were self-administering THC or a similar synthetic drug by pushing a lever.
They found the rodents and monkeys were less likely to administer the THC or synthetic drug when they were on the dopamine-stifling drug, the researchers report online today (Oct. 13) in the journal Nature Neuroscience.
In another experiment, the researchers took the animals off of the THC or synthetic drug for a while, and then increased their kynurenic acid levels while giving them a small dose of THC, or a cue associated with taking the drug.
Boosting kynurenic acid prevented the animals from returning to their old drug abuse patterns. "We found that you can reduce dopamine levels and the animals behave differently — they don't have relapse, and don't abuse marijuana," Schwarcz told LiveScience.
While the results are promising, they have not yet been validated in humans. Furthermore, its possible the drug used to treat marijuana addiction could act on other parts of the brain, not only those involved in marijuana addiction.
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You'll Be Less Anxious
Even though smokers may believe taking a long drag on a cigarette can help to calm nerves, a British study published earlier this year suggests that <em>quitting</em> can actually decrease anxiety more over the long-term. "People who achieve abstinence experience a <a href="http://www.cbc.ca/news/health/story/2013/01/02/smoking-quit-anxiety.html">marked reduction in anxiety</a> whereas those who fail to quit experience a modest increase in the long term," researchers wrote in the British Journal of Psychiatry study, as reported by CBC News. Similarly, a 2010 study in the journal Addiction showed that <a href="http://www.reuters.com/article/2010/06/17/us-smoking-idUSTRE65G0CX20100617">perceived stress decreased</a> for people who quit smoking for a year after hospitalization for heart disease, Reuters reported.
Your Mouth Will Thank You
Quitting the habit could dramatically <a href="http://consumer.healthday.com/Article.asp?AID=661533">decrease your risk of dental problems</a> like cavities and gum disease, and even more dangerous conditions like oral cancer, according to a study from the Centers for Disease Control and Prevention. HealthDay reported that <a href="http://consumer.healthday.com/Article.asp?AID=661533">compared with former smokers</a>, smokers have a 1.5-times higher risk of developing at least three oral health conditions.
Your Sex Life Will Be Better
Here's a bedroom-related reason to quit smoking: studies have suggested a link between smoking and decreased sex drives for both men <em>and</em> women. Studies published in 2008 in the Journal of Sexual Medicine showed that nicotine can affect even <a href="http://www.ncbi.nlm.nih.gov/pubmed/17971108">nonsmoking men's</a> and <a href="http://www.ncbi.nlm.nih.gov/pubmed/18331269">women's sexual arousal</a>. And if that's not enough to convince you, well, there's also <a href="http://healthland.time.com/2011/09/15/guys-quitting-smoking-makes-it-bigger-really/">this</a>.
You'll Save Your Skin
If you want your skin to be at its best, then you're better off quitting cigarettes. WebMD points out that smoking <a href="http://www.webmd.com/smoking-cessation/ss/slideshow-ways-smoking-affects-looks">affects skin tone</a>, promotes sagginess and, of course, causes those wrinkles around the lip area. However, the American Society for Aesthetic Plastic Surgery notes that just a month-and-a-half after <a href="http://www.surgery.org/consumers/plastic-surgery-news-briefs/skin-quit-smoking-1031403">quitting smoking</a>, your skin will already begin to look better.
You'll Have More Locks
If you love your hair, maybe it's time to put the cigarettes down. Research has linked smoking with an increased risk of male pattern baldness. BBC News reported in 2007 on a Archives of Dermatology study, showing even after taking into account other hair-loss risk factors like age and race, <a href="http://news.bbc.co.uk/2/hi/health/5413382.stm">heavy smoking</a> (at least 20 cigarettes daily) raised the risk of baldness. And a 2011 study showed that smoking, stress, drinking and genes were all<a href="http://www.webmd.com/skin-problems-and-treatments/hair-loss/news/20110923/divorce-heavy-drinking-smoking-linked-to-hair-loss"> risk factors for baldness</a>, WebMD reported.
Your Mood Will Improve
Here's a pretty good benefit: Stopping smoking could <a href="http://news.brown.edu/pressreleases/2010/12/smoking">make you a happier person</a>, according to research from Brown University. Researchers there found that smokers were <a href="http://news.brown.edu/pressreleases/2010/12/smoking">never happier</a> than when they were quitting smoking, even if they went back to smoking afterward. According to a <a href="http://news.brown.edu/pressreleases/2010/12/smoking">news release</a>: <blockquote> The most illustrative — and somewhat tragic — subjects were the ones who only quit temporarily. Their moods were clearly brightest at the checkups when they were abstinent. After going back to smoking, their mood darkened, in some cases to higher levels of sadness than before.</blockquote>
You'll Have More Birthdays
Stopping smoking may <a href="http://www.huffingtonpost.com/2012/10/29/women-stop-smoking-live-10-years-longer_n_2011804.html">help women live a decade longer</a> than they would have if they had continued lighting up, according to a 2012 study in The Lancet. Researchers also found that the more the women smoked, the higher their risk of premature death, with even "light" smokers (those who smoked just one to nine cigarettes a day) having a doubled risk of death compared with non-smokers. "If women smoke like men, they die like men -- but, whether they are men or women, smokers who stop before reaching middle age will on average <a href="http://www.eurekalert.org/pub_releases/2012-10/l-soa102312.php">gain about an extra ten years of life</a>," study researcher Professor Sir Richard Peto, of the University of Oxford, said in a statement.
You'll Improve Your Pregnancy Chances
If you're trying to conceive, one of the best things you can do is to quit smoking, research shows. NBC News reported that women smokers have a 60 percent <a href="http://today.msnbc.msn.com/id/16874634/ns/today-today_health/t/trying-conceive-quit-smoking/#.UOr-7onjlU4">higher chance of being infertile</a>, compared with nonsmokers. Smoking is also linked to more spontaneous miscarriages, according to NBC News.
You'll Enjoy Food More
If you <a href="http://abcnews.go.com/Health/Healthday/story?id=8427779#.UOsAFInjlU4">don't like bland food</a>, then don't smoke, research suggests. A small 2009 study of Greek soldiers shows an association between smoking and <a href="http://www.eurekalert.org/pub_releases/2009-08/bc-stf081809.php">"fewer and flatter" taste buds</a>, according to a statement on the research.
Your Colds Won't Be As Bad
Mild cold symptoms could take on a more serious form for smokers, according to a study from Yale University researchers. The findings, published in 2008 in the Journal of Clinical Investigation, showed an <a href="http://news.yale.edu/2008/07/24/study-shows-why-cigarette-smoke-makes-flu-other-viral-infections-worse">overreaction of the immune systems</a> of cigarette smoke-exposed mice when exposed to a virus similar to the flu. "The anti-viral responses in the cigarette smoke exposed mice were not only not defective, but were hyperactive," study researcher Dr. Jack A. Elias, M.D., said in a statement. "These findings suggest that smokers do not get in trouble because they can't clear or<a href="http://news.yale.edu/2008/07/24/study-shows-why-cigarette-smoke-makes-flu-other-viral-infections-worse"> fight off the virus</a>; they get in trouble because they overreact to it."
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