Chapter 4. The Chemistry of Behavior: Neurotransmitters and Neuropharmacology

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 1849

|By Roni Jacobson Almost immediately after Albert Hofmann discovered the hallucinogenic properties of LSD in the 1940s, research on psychedelic drugs took off. These consciousness-altering drugs showed promise for treating anxiety, depression, post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD) and addiction, but increasing government conservatism caused a research blackout that lasted decades. Lately, however, there has been a resurgence of interest in psychedelics as possible therapeutic agents. This past spring Swiss researchers published results from the first drug trial involving LSD in more than 40 years. Although the freeze on psychedelic research is thawing, scientists say that restrictive drug policies are continuing to hinder their progress. In the U.S., LSD, psilocybin, MDMA, DMT, peyote, cannabis and ibogaine (a hallucinogen derived from an African shrub) are all classified as Schedule I illegal drugs, which the U.S. Drug Enforcement Administration defines as having a high potential for abuse and no currently accepted medical applications—despite extensive scientific evidence to the contrary. In a joint report released in June, the Drug Policy Alliance and the Multidisciplinary Association for Psychedelic Studies catalogue several ways in which they say that the DEA has unfairly obstructed research on psychedelics, including by overruling an internal recommendation in 1986 that MDMA be placed on a less restrictive schedule. The DEA and the U.S. Food and Drug Administration maintain that there is insufficient research to justify recategorization. This stance creates a catch-22 by basing the decision on the need for more research while limiting the ability of scientists to conduct that research. © 2014 Scientific American

Keyword: Depression; Aggression
Link ID: 20004 - Posted: 08.28.2014

Daniel Cressey In many respects, the modern electronic cigarette is not so different from its leaf-and-paper predecessor. Take a drag from the mouthpiece and you get a genuine nicotine fix — albeit from a fluid wicked into the chamber of a battery-powered atomizer and vaporized by a heating element. Users exhale a half-convincing cloud of ‘smoke’, and many e-cigarettes even sport an LED at the tip that glows blue, green or classic red to better simulate the experience romanticized by countless writers and film-makers. The only things missing are the dozens of cancer-causing chemicals found in this digital wonder’s analogue forebears. E-cigarettes — also known as personal vaporizers or electronic nicotine-delivery systems among other names — are perhaps the most disruptive devices that public-health researchers working on tobacco control have ever faced. To some, they promise to snuff out a behaviour responsible for around 100 million deaths in the twentieth century. Others fear that they could perpetuate the habit, and undo decades of work. Now, a group once united against a common enemy is divided. “These devices have really polarized the tobacco-control community,” says Michael Siegel, a physician and tobacco researcher at Boston University School of Public Health in Massachusetts. “You now have two completely opposite extremes with almost no common ground between them.” Evidence is in short supply on both sides. Even when studies do appear, they are often furiously debated. And it is not just researchers who are attempting to catch up with the products now pouring out of Chinese factories: conventional tobacco companies are pushing into the nascent industry, and regulators are scrambling to work out what to do. © 2014 Nature Publishing Group

Keyword: Drug Abuse
Link ID: 20000 - Posted: 08.27.2014

By Chelsea Rice Opioid-related overdose deaths are a bleak public health issue in this country. The percentage of patients who receive opioid prescriptions to treat noncancer pain has almost doubled in the past decade, but the number of overdose-related deaths for women have increased five times as much, according to the Centers for Disease Control and Prevention. To put the nationwide stats in perspective, more women have died each year from drug overdoses than from motor vehicle-related injuries since 2007. For men in the past decade, the rate of opioid overdose deaths has increased three-fold. According to the CDC, women in particular are more likely to be prescribed opioid pain relievers than men, more likely to use them chronically, and more likely to be prescribed them in higher doses. But what if medical marijuana, another option for treating chronic pain, could have an impact on these staggering statistics? Research published today in JAMA Internal Medicine found that states with medical marijuana laws before 2010 had 24.8 percent lower annual opioid overdose deaths on average when compared to states where medical marijuana was illegal. Medical cannabis laws were associated in the study with lower overdose mortality rates that generally strengthened over time. In 2010, for instance, researchers noticed there were 1,729 fewer deaths in states where medical marijuana was legal. The research team, lead by Dr. Marcus A. Bachhuber at the Philadelphia Veterans Affairs Medical Center, examined state medical marijuana laws and opioid overdose deaths using death certificate data from 1999 to 2010.

Keyword: Drug Abuse
Link ID: 19993 - Posted: 08.26.2014

By DAVE PHILIPPS WRAY, Colo. — Behind a tall curtain of corn that hides their real cash crop from prying eyes, the Stanley family is undertaking an audacious effort to expand their medical marijuana business to a national market. For years, the five Stanley brothers, who sell a nonintoxicating strain of cannabis that has gained national attention as a treatment for epilepsy, have grown medical marijuana in greenhouses, under tight state and federal regulations. But this year, they are not only growing marijuana outdoors by the acre, they also plan to ship an oil extracted from their plants to other states. The plan would seem to defy a federal prohibition on the sale of marijuana products across state lines. But the Stanleys have justified it with a simple semantic swap: They now call their crop industrial hemp, based on its low levels of THC, the psychoactive ingredient in pot. “The jump to industrial hemp means we can serve thousands of people instead of hundreds,” said Jared Stanley, 27, who wore muddy Carhartts and a rainbow friendship bracelet as he knelt down to prune his plants. Colorado, which has legalized the sale of marijuana for recreational and medical use, has accepted the new designation. But the real question is whether the federal government will go along. If it does, the impact would be significant, opening the door to interstate sales not just by the Stanleys, but possibly by scores of other medical cannabis growers across the country. But if it does not, the Stanley brothers could be shut down by federal agents. So far, the Drug Enforcement Administration is offering few clues, insisting in public statements that while it is willing to allow marijuana sales in states that have legalized the drug, it might step in if growers try to sell beyond state borders. © 2014 The New York Times Company

Keyword: Drug Abuse
Link ID: 19990 - Posted: 08.25.2014

By TARA PARKER-POPE When the antidrug educator Tim Ryan talks to students, he often asks them what they know about marijuana. “It’s a plant,” is a common response. But more recently, the answer has changed. Now they reply, “It’s legal in Colorado.” These are confusing times for middle and high school students, who for most of their young lives have been lectured about the perils of substance abuse, particularly marijuana. Now it seems that the adults in their lives have done an about-face. Recreational marijuana is legal in Colorado and in Washington, and many other states have approved it for medical use. Lawmakers, the news media and even parents are debating the merits of full-scale legalization. “They are growing up in a generation where marijuana used to be bad, and maybe now it’s not bad,” said Mr. Ryan, a senior prevention specialist with FCD Educational Services, an antidrug group that works with students in the classroom. “Their parents are telling them not to do it, but they may be supporting legalization of it at the same time.” Antidrug advocates say efforts to legalize marijuana have created new challenges as they work to educate teenagers and their parents about the unique risks that alcohol, marijuana and other drugs pose to the developing teenage brain. These educators say their goal is not to vilify marijuana or take a stand on legalization; instead, they say their role is to convince young people and their parents that the use of drugs is not just a moral or legal issue, but a significant health issue. “The health risks are real,” said Steve Pasierb, the chief executive of the Partnership for Drug-Free Kids. “Every passing year, science unearths more health risks about why any form of substance use is unhealthy for young people.” © 2014 The New York Times Company

Keyword: Drug Abuse; Aggression
Link ID: 19976 - Posted: 08.19.2014

By NICHOLAS BAKALAR A new study reports that caffeine intake is associated with a reduced risk for tinnitus — ringing or buzzing in the ears. Researchers tracked caffeine use and incidents of tinnitus in 65,085 women in the Nurses’ Health Study II. They were 30 to 34 and without tinnitus at the start of the study. Over the next 18 years, 5,289 developed the disorder. The women recorded their use of soda, coffee and tea (caffeinated and not), as well as intake of candy and chocolate, which can contain caffeine. The results appear in the August issue of The American Journal of Medicine. Compared with women who consumed less than 150 milligrams of caffeine a day (roughly the amount in an eight-ounce cup of coffee), those who had 450 to 599 milligrams a day were 15 percent less likely to have tinnitus, and those who consumed 600 milligrams or more were 21 percent less likely. The association persisted after controlling for other hearing problems, hypertension, diabetes, use of anti-inflammatory Nsaid drugs, a history of depression and other factors. Decaffeinated coffee consumption had no effect on tinnitus risk. “We can’t conclude that caffeine is a cure for tinnitus,” said the lead author, Dr. Jordan T. Glicksman, a resident physician at the University of Western Ontario. “But our results should provide some assurance to people who do drink caffeine that it’s reasonable to continue doing so.” © 2014 The New York Times Company

Keyword: Hearing
Link ID: 19955 - Posted: 08.14.2014

Sara Reardon When the states of Colorado and Washington voted to legalize marijuana in 2012, the abrupt and unprecedented policy switch sent the US National Institute on Drug Abuse (NIDA) into what its director Nora Volkow describes as “red alarm”. Although marijuana remained illegal for people under the age of 21, the drug’s increased availability and growing public acceptance suggested that teenagers might be more likely to try it (see ‘Highs and lows’). Almost nothing is known about whether or how marijuana affects the developing adolescent brain, especially when used with alcohol and other drugs. The new laws, along with advances in brain-imaging technology, convinced Volkow to accelerate the launch of an ambitious effort to follow 10,000 US adolescents for ten years in an attempt to determine whether marijuana, alcohol and nicotine use are associated with changes in brain function and behaviour. At a likely cost of more than US$300 million, it will be the largest longitudinal brain-imaging study of adolescents yet. Researchers are eager to study a poorly understood period of human development — but some question whether it is possible to design a programme that will provide useful information about the effects of drugs. “It’s definitely an idea that’s overdue,” says Deanna Barch, a psychologist at Washington University in St. Louis, Missouri. “The downside is it’s a lot of eggs in one basket.” © 2014 Nature Publishing Group,

Keyword: Development of the Brain; Aggression
Link ID: 19949 - Posted: 08.13.2014

By Lenny Bernstein, Lena H. Sun and Sandhya Somashekhar Suicides are the 10th-leading cause of death in the United States and eighth among people in the 55- to 64-year-old age group. Comedian Robin Williams, who died Monday of an apparent suicide, was 63. In 2010, 38,364 people died this way. Many suicides are the result of undiagnosed or untreated depression, often masked by self-medicating behaviors such as alcohol and drug use. Though we don’t yet know the exact circumstances of Williams’s death, we do know that he long battled addictions to cocaine and alcohol and, according to his publicist, was struggling with “severe depression.” But unlike many people, Williams had the resources and the motivation to seek treatment, at least for his addictions. According to this report, he had undergone rehab at the famed Hazelden Addiction Treatment Center in Minnesota two months ago, and had sought treatment in 2006 when he began drinking again after 20 years of sobriety. How, then, do we explain the death of someone who appeared to recognize the danger he faced and was trying to address it? Here are some thoughts: • Suicides are often impulsive acts: People who kill themselves are not thinking clearly, have trouble solving problems and weigh risks differently from us, Jill Harkavy-Friedman, vice president of research for the American Foundation for Suicide Prevention, told To Your Health in March. If thwarted in their first attempt, they often do not try again immediately, she said.

Keyword: Depression; Aggression
Link ID: 19947 - Posted: 08.13.2014

By KATHARINE Q. SEELYE SPARTA, N.J. — When Gail Morris came home late one night after taking her daughter to college, she saw her teenage son, Alex, asleep on the sofa in the family room. Nothing seemed amiss. An unfinished glass of apple juice sat on the table. She tucked him in under a blanket and went to bed. The next morning, he would not wake up. He was stiff and was hardly breathing. Over the next several hours, Ms. Morris was shocked to learn that her son had overdosed on heroin. She was told he would not survive. He did survive, but barely. He was in a coma for six weeks. He went blind and had no function in his arms or legs. He could not speak or swallow. Hospitalized for 14 months, Alex, who is 6-foot-1, dropped to 90 pounds. One of his doctors said that Alex had come as close to dying as anyone he knew who had not actually died. Most people who overdose on heroin either die or fully recover. But Alex plunged into a state that was neither dead nor functional. There are no national statistics on how often opioid overdose leads to cases like Alex’s, but doctors say they worry that with the dramatic increase in heroin abuse and overdoses, they will see more such outcomes. “I would expect that we will,” said Dr. Nora Volkow, director of the National Institute on Drug Abuse. “They are starting to report isolated cases like this. And I would not be surprised if you have more intermediate cases with more subtle impairment.” More than 660,000 Americans used heroin in 2012, the federal government says, double the number of five years earlier. Officials attribute much of the increase to a crackdown on prescription painkillers, prompting many users to turn to heroin, which is cheaper and easier to get than other opioids. © 2014 The New York Times Company

Keyword: Consciousness; Aggression
Link ID: 19935 - Posted: 08.11.2014

By SERGE F. KOVALESKI Nearly four years ago, Dr. Sue Sisley, a psychiatrist at the University of Arizona, sought federal approval to study marijuana’s effectiveness in treating military veterans with post-traumatic stress disorder. She had no idea how difficult it would be. The proposal, which has the support of veterans groups, was hung up at several regulatory stages, requiring the research’s private sponsor to resubmit multiple times. After the proposed study received final approval in March from federal health officials, the lone federal supplier of research marijuana said it did not have the strains the study needed and would have to grow more — potentially delaying the project until at least early next year. Then, in June, the university fired Dr. Sisley, later citing funding and reorganization issues. But Dr. Sisley is convinced the real reason was her outspoken support for marijuana research. “They could never get comfortable with the idea of this controversial, high-profile research happening on campus,” she said. Dr. Sisley’s case is an extreme example of the obstacles and frustrations scientists face in trying to study the medical uses of marijuana. Dating back to 1999, the Department of Health and Human Services has indicated it does not see much potential for developing marijuana in smoked form into an approved prescription drug. In guidelines issued that year for research on medical marijuana, the agency quoted from an accompanying report that stated, “If there is any future for marijuana as a medicine, it lies in its isolated components, the cannabinoids and their synthetic derivatives.” Scientists say this position has had a chilling effect on marijuana research. © 2014 The New York Times Company

Keyword: Drug Abuse
Link ID: 19933 - Posted: 08.11.2014

by Bethany Brookshire Every day sees a new research article on addiction, be it cocaine, heroin, food or porn. Each one takes a specific angle on how addiction works in the brain. Perhaps it’s a disorder of reward, with drugs hijacking a natural system that is meant to respond to food, sex and friendship. Possibly addiction is a disorder of learning, where our brains learn bad habits and responses. Maybe we should think of addiction as a combination of an environmental stimulus and vulnerable genes. Or perhaps it’s an inappropriate response to stress, where bad days trigger a relapse to the cigarette, syringe or bottle. None of these views are wrong. But none of them are complete, either. Addiction is a disorder of reward, a disorder of learning. It has genetic, epigenetic and environmental influences. It is all of that and more. Addiction is a display of the brain’s astounding ability to change — a feature called plasticity — and it showcases what we know and don’t yet know about how brains adapt to all that we throw at them. “A lot of people think addiction is what happens when someone finds a drug to be the most rewarding thing they’ve ever experienced,” says neuroscientist George Koob, director of the National Institute on Alcohol Abuse and Alcoholism in Bethesda, Md. “But drug abuse is not just feeling good about drugs. Your brain is changed when you misuse drugs. It is changed in ways that perpetuate the problem.” The changes associated with drug use affect how addicts respond to drug cues, like the smell of a cigarette or the sight of a shot of vodka. Drug abuse also changes how other rewards, such as money or food are processed, decreasing their relative value. © Society for Science & the Public 2000 - 2013

Keyword: Drug Abuse; Aggression
Link ID: 19921 - Posted: 08.06.2014

By PHILIP M. BOFFEY For Michele Leonhart, the administrator of the Drug Enforcement Administration, there is no difference between the health effects of marijuana and those of any other illegal drug. “All illegal drugs are bad for people,” she told Congress in 2012, refusing to say whether crack, methamphetamines or prescription painkillers are more addictive or physically harmful than marijuana. Her testimony neatly illustrates the vast gap between antiquated federal law enforcement policies and the clear consensus of science that marijuana is far less harmful to human health than most other banned drugs and is less dangerous than the highly addictive but perfectly legal substances known as alcohol and tobacco. Marijuana cannot lead to a fatal overdose. There is little evidence that it causes cancer. Its addictive properties, while present, are low, and the myth that it leads users to more powerful drugs has long since been disproved. That doesn’t mean marijuana is harmless; in fact, the potency of current strains may shock those who haven’t tried it for decades, particularly when ingested as food. It can produce a serious dependency, and constant use would interfere with job and school performance. It needs to be kept out of the hands of minors. But, on balance, its downsides are not reasons to impose criminal penalties on its possession, particularly not in a society that permits nicotine use and celebrates drinking. Marijuana’s negative health effects are arguments for the same strong regulation that has been effective in curbing abuse of legal substances. Science and government have learned a great deal, for example, about how to keep alcohol out of the hands of minors. Mandatory underage drinking laws and effective marketing campaigns have reduced underage alcohol use to 24.8 percent in 2011, compared with 33.4 percent in 1991. Cigarette use among high school students is at its lowest point ever, largely thanks to tobacco taxes and growing municipal smoking limits. There is already some early evidence that regulation would also help combat teen marijuana use, which fell after Colorado began broadly regulating medical marijuana in 2010. © 2014 The New York Times Company

Keyword: Drug Abuse
Link ID: 19909 - Posted: 08.02.2014

By BRENT STAPLES The federal law that makes possession of marijuana a crime has its origins in legislation that was passed in an atmosphere of hysteria during the 1930s and that was firmly rooted in prejudices against Mexican immigrants and African-Americans, who were associated with marijuana use at the time. This racially freighted history lives on in current federal policy, which is so driven by myth and propaganda that it is almost impervious to reason. The cannabis plant, also known as hemp, was widely grown in the United States for use in fabric during the mid-19th century. The practice of smoking it appeared in Texas border towns around 1900, brought by Mexican immigrants who cultivated cannabis as an intoxicant and for medicinal purposes as they had done at home. Within 15 years or so, it was plentiful along the Texas border and was advertised openly at grocery markets and drugstores, some of which shipped small packets by mail to customers in other states. The law enforcement view of marijuana was indelibly shaped by the fact that it was initially connected to brown people from Mexico and subsequently with black and poor communities in this country. Police in Texas border towns demonized the plant in racial terms as the drug of “immoral” populations who were promptly labeled “fiends.” As the legal scholars Richard Bonnie and Charles Whitebread explain in their authoritative history, “The Marihuana Conviction,” the drug’s popularity among minorities and other groups practically ensured that it would be classified as a “narcotic,” attributed with addictive qualities it did not have, and set alongside far more dangerous drugs like heroin and morphine. © 2014 The New York Times Company

Keyword: Drug Abuse
Link ID: 19903 - Posted: 07.31.2014

By Marek Kohn “You know how they say that we can only access 20% of our brain?” says the man who offers stressed-out writer Eddie Morra a fateful pill in the 2011 film Limitless. “Well, what this does, it lets you access all of it.” Morra is instantly transformed into a superhuman by the fictitious drug NZT-48. Granted access to all cognitive areas, he learns to play the piano in three days, finishes writing his book in four, and swiftly makes himself a millionaire. Limitless is what you get when you flatter yourself that your head houses the most complex known object in the universe, and you run away with the notion that it must have powers to match. A number of so-called ‘smart drugs’ or cognitive enhancers have captured attention recently, from stimulants such as modafinil, to amphetamines (often prescribed under the name Adderall) and methylphenidate (also known by its brand name Ritalin). According to widespread news reports, students have begun using these drugs to enhance their performance in school and college, and are continuing to do so in their professional lives. Yet are these smart drugs all they are cracked up to be? Can they really make all of us more intelligent or learn more? Should we be asking deeper questions about what these pharmaceuticals can and can’t do? BBC © 2014

Keyword: ADHD; Aggression
Link ID: 19897 - Posted: 07.30.2014

by Helen Thomson How do you smell after a drink? Quite well, it turns out. A modest amount of alcohol boosts your sense of smell. It is well known that we can improve our sense of smell through practice. But a few people have also experienced a boost after drug use or brain damage. This suggests our sensitivity to smell may be damped by some sort of inhibition in the brain, which can be lifted under some circumstances, says Yaara Endevelt of the Weizmann Institute of Science in Rehovot, Israel. To explore this notion, Endevelt and her colleagues investigated whether drinking alcohol – known to lower inhibitory signals in the brain – affected the sense of smell. In one odour-discrimination test, 20 volunteers were asked to smell three different liquids. Two were a mixture of the same six odours, the third contained a similar mixture with one odour replaced. Each volunteer was given 2 seconds to smell each of the liquids and say which was the odd one out. The test was repeated six times with each of three trios of liquids. They were then given a drink that consisted of 35 millilitres of vodka and sweetened grape juice, or the juice alone, before repeating the experiment with the same set of liquids. In a second experiment with a similar drinking structure, the same volunteers were asked which of three liquids had a rose-like odour. The researchers increased the concentration of the odour until the volunteers got the right answer three times in a row. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 19875 - Posted: 07.24.2014

By ANN SANNER Associated Press COLUMBUS, Ohio (AP) — A few weeks before their prom king’s death, students at an Ohio high school had attended an assembly on narcotics that warned about the dangers of heroin and prescription painkillers. But it was one of the world’s most widely accepted drugs that killed Logan Stiner — a powdered form of caffeine so potent that as little as a single teaspoon can be fatal. The teen’s sudden death in May has focused attention on the unregulated powder and drawn a warning from federal health authorities urging consumers to avoid it. ‘‘I don’t think any of us really knew that this stuff was out there,’’ said Jay Arbaugh, superintendent of the Keystone Local Schools. The federal Food and Drug Administration said Friday that it’s investigating caffeine powder and will consider taking regulatory action. The agency cautioned parents that young people could be drawn to it. An autopsy found that Stiner had a lethal amount of caffeine in his system when he died May 27 at his home in LaGrange, Ohio, southwest of Cleveland. Stiner, a wrestler, had more than 70 micrograms of caffeine per milliliter of blood in his system, as much as 23 times the amount found in a typical coffee or soda drinker, according to the county coroner. His mother has said she was unaware her son took caffeine powder. He was just days away from graduation and had planned to study at the University of Toledo. Caffeine powder is sold as a dietary supplement, so it’s not subject to the same federal regulations as certain caffeinated foods. Users add it to drinks for a pick-me-up before workouts or to control weight gain. A mere 1/16th of a teaspoon can contain about 200 milligrams of caffeine, roughly the equivalent of two large cups of coffee. That means a heaping teaspoon could kill, said Dr. Robert Glatter, an emergency physician at Lenox Hill ?Hospital in New York.

Keyword: Drug Abuse
Link ID: 19857 - Posted: 07.21.2014

By Lizzie Wade This week, a team from the National Institute on Drug Abuse (NIDA) reported that heavy marijuana use may damage the brain's pleasure center. Meanwhile, researchers in the United Kingdom say they’ve figured out why pot makes you paranoid. But does focusing research on cannabis’s “bad side” give the drug short shrift? Science talked to Ian Mitchell, an emergency physician at the University of British Columbia’s Southern Medical Program in Kamloops, Canada, and author of the blog Clinical Cannabis in Context, who says that politics influences research in this controversial field. As a doctor who recommends medical cannabis to patients, he follows research on the drug and often critiques studies he believes are based on outdated information or were performed with an anticannabis bias. This interview has been edited for clarity and brevity. Q: What do you think of the NIDA study? A: They said they gave marijuana abusers Ritalin and nothing happened. One of the ways you could interpret that is, OK, these pleasure centers are damaged. But you could also say, perhaps marijuana decreases the effects of [Ritalin] on people. That would be equally as right an interpretation. Q: Why do we hear more about studies that show negative effects of marijuana? A: NIDA is at the center of cannabis research in America. And their mandate, very plainly, is to study drug abuse. So they overwhelmingly fund studies that look at abuse. In America, if you wanted to run a study that showed a benefit of cannabis, you weren’t allowed to do that because NIDA couldn’t give you samples to use. So there were no trials [on potential medical benefits] being done. For example, there hasn’t been a good trial yet to study marijuana’s potential for treating posttraumatic stress disorder. They couldn’t get it done, due to all these political roadblocks. © 2014 American Association for the Advancement of Science

Keyword: Drug Abuse; Aggression
Link ID: 19843 - Posted: 07.17.2014

By Lizzie Wade It probably won’t come as a surprise that smoking a joint now and then will leave you feeling … pretty good, man. But smoking a lot of marijuana over a long time might do just the opposite. Scientists have found that the brains of pot abusers react less strongly to the chemical dopamine, which is responsible for creating feelings of pleasure and reward. Their blunted dopamine responses could leave heavy marijuana users living in a fog—and not the good kind. After high-profile legalizations in Colorado, Washington, and Uruguay, marijuana is becoming more and more available in many parts of the world. Still, scientific research on the drug has lagged. Pot contains lots of different chemicals, and scientists don’t fully understand how those components interact to produce the unique effects of different strains. Its illicit status in most of the world has also thrown up barriers to research. In the United States, for example, any study involving marijuana requires approval from four different federal agencies, including the Drug Enforcement Administration. One of the unanswered questions about the drug is what, exactly, it does to our brains, both during the high and afterward. Of particular interest to scientists is marijuana’s effect on dopamine, a main ingredient in the brain’s reward system. Pleasurable activities such as eating, sex, and some drugs all trigger bursts of dopamine, essentially telling the brain, “Hey, that was great—let’s do it again soon.” Scientists know that drug abuse can wreak havoc on the dopamine system. Cocaine and alcohol abusers, for example, are known to produce far less dopamine in their brains than people who aren’t addicted to those drugs. But past studies had hinted that the same might not be true for those who abuse marijuana. © 2014 American Association for the Advancement of Science

Keyword: Drug Abuse
Link ID: 19832 - Posted: 07.15.2014

|By Maria Burke and ChemistryWorld The world needs to tackle head-on the market failures undermining dementia research and drug development, UK Prime Minister David Cameron told a summit of world health and finance leaders in London in June. He announced an investigation into how to get medicines to patients earlier, extend patents and facilitate research collaborations, to report this autumn. But just how much difference will these sorts of measures make when scientists are still grappling with exactly what causes different types of dementia? Added to these problems is that dementia has become a graveyard for a large number of promising drugs. A recent study looked at how 244 compounds in 413 clinical trials fared for Alzheimer's disease between 2002 and 2012. The researchers findings paint a gloomy picture. Of those 244 compounds, only one was approved. The researchers report that this gives Alzheimer's disease drug candidates one of the highest failures rates of any disease area – 99.6%, compared with 81% for cancer. ‘Dementia is a ticking bomb costing the global economy £350 billion and yet progress with research is achingly slow,’ warned the World Dementia Envoy, Dennis Gillings. Businesses need incentives to invest in research and bring in faster, cheaper clinical trials, or the world won’t meet the ambition to find a cure or disease-modifying therapy by 2025, he added. ‘We need to free up regulation so that we can test ground-breaking new drugs, and examine whether the period for market exclusivity could be extended.’ © 2014 Scientific American

Keyword: Alzheimers
Link ID: 19828 - Posted: 07.15.2014

By Jules Wellinghoff A simple change in electric charge may make the difference between someone getting the medicine they need and a trip to the emergency room—at least if a new study bears out. Researchers investigating the toxicity of particles designed to ferry drugs inside the body have found that carriers with a positive charge on their surface appear to cause damage if they reach the brain. These particles, called micelles, are one type of a class of materials known as nanoparticles. By varying properties such as charge, composition, and attached surface molecules, researchers can design nanoparticles to deliver medicine to specific body regions and cell types—and even to carry medicine into cells. This ability allows drugs to directly target locations they would otherwise be unable to, such as the heart of tumors. Researchers are also looking at nanoparticles as a way to transport drugs across the blood-brain barrier, a wall of tightly connected cells that keeps most medication out of the brain. Just how safe nanoparticles in the brain are, however, remains unclear. So Kristina Bram Knudsen, a toxicologist at the National Research Centre for the Working Environment in Copenhagen, and colleagues tested two types of micelles, which were made from different polymers that gave the micelles either a positive or negative surface charge. They injected both versions, empty of drugs, into the brains of rats, and 1 week later they checked for damage. Three out of the five rats injected with the positively charged micelles developed brain lesions. The rats injected with the negatively charged micelles or a saline control solution did not suffer any observable harm from the injections, the team will report in an upcoming issue of Nanotoxicology. © 2014 American Association for the Advancement of Science

Keyword: Neurotoxins
Link ID: 19819 - Posted: 07.12.2014