Sleepless night, the moon is bright. People sleep less soundly when there's a full moon, researchers discovered when they analyzed data from a past sleep study. If you were tossing and turning and howling at your pillow this week, you’re not necessarily a lunatic, at least in the strictest sense of the word. The recent full moon might be to blame for your poor sleep. In the days close to a full moon, people take longer to doze off, sleep less deeply, and sleep for a shorter time, even if the moon isn’t shining in their window, a new study has found. “A lot of people are going to say, ‘Yeah, I knew this already. I never sleep well during a full moon.’ But this is the first data that really confirms it,” says biologist Christian Cajochen of the University of Basel in Switzerland, lead author of the new work. “There had been numerous studies before, but many were very inconclusive.” Anecdotal evidence has long suggested that people’s sleep patterns, moods, and even aggression is linked to moon cycles. But past studies of potential lunar effects have been tainted by statistical weaknesses, biases, or inconsistent methods, Cajochen says. Between 2000 and 2003, he and his colleagues had collected detailed data on the sleep patterns of 33 healthy volunteers for an unrelated study on the effects of aging on sleep. Using electroencephalograms (EEG) that measure brain activity, they recorded how deep and how long each participant’s nightly sleep was in a controlled, laboratory setting. Years after the initial experiment, the scientists were drinking in a pub—during a full moon—and came up with the idea of going back to the data to test for correlations with moon cycles. © 2012 American Association for the Advancement of Science.

Keyword: Sleep; Biological Rhythms
Link ID: 18415 - Posted: 07.27.2013

Brain cells talk to each other in a variety of tones. Sometimes they speak loudly but other times struggle to be heard. For many years scientists have asked why and how brain cells change tones so frequently. Today National Institutes of Health researchers showed that brief bursts of chemical energy coming from rapidly moving power plants, called mitochondria, may tune brain cell communication. “We are very excited about the findings,” said Zu-Hang Sheng, Ph.D., a senior principal investigator and the chief of the Synaptic Functions Section at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS). “We may have answered a long-standing, fundamental question about how brain cells communicate with each other in a variety of voice tones.” The network of nerve cells throughout the body typically controls thoughts, movements and senses by sending thousands of neurotransmitters, or brain chemicals, at communication points made between the cells called synapses. Neurotransmitters are sent from tiny protrusions found on nerve cells, called presynaptic boutons. Boutons are aligned, like beads on a string, on long, thin structures called axons. They help control the strength of the signals sent by regulating the amount and manner that nerve cells release transmitters. Mitochondria are known as the cell’s power plant because they use oxygen to convert many of the chemicals cells use as food into adenosine triphosphate (ATP), the main energy that powers cells. This energy is essential for nerve cell survival and communication. Previous studies showed that mitochondria can rapidly move along axons, dancing from one bouton to another.

Keyword: Miscellaneous
Link ID: 18414 - Posted: 07.27.2013

By Meghan Rosen In a spacious hotel room not far from the beach in La Jolla, Calif., Kelsey Heenan gripped her fiancé’s hand. Heenan, a 20-year-old anorexic woman, couldn’t believe what she was hearing. Walter Kaye, director of the eating disorders program at the University of California, San Diego, was telling a handful of rapt patients and their family members what the latest brain imaging research suggested about their disorder. It’s not your fault, he told them. Heenan had always assumed that she was to blame for her illness. Kaye’s data told a different story. He handed out a pile of black-and-white brain scans — some showed the brains of healthy people, others were from people with anorexia nervosa. The scans didn’t look the same. “People were shocked,” Heenan says. But above all, she remembers, the group seemed to sigh in relief, breathing out years of buried guilt about the disorder. “It’s something in the way I was wired — it’s something I didn’t choose to do,” Heenan says. “It was pretty freeing to know that there could be something else going on.” Years of psychological and behavioral research have helped scientists better understand some signs and triggers of anorexia. But that knowledge hasn’t straightened out the disorder’s tangled roots, or pointed scientists to a therapy that works for everyone. “Anorexia has a high death rate, it’s expensive to treat and people are chronically ill,” says Kaye. © Society for Science & the Public 2000 - 2013

Keyword: Anorexia & Bulimia
Link ID: 18413 - Posted: 07.27.2013

Heidi Ledford A procedure increasingly used to treat obesity by reducing the size of the stomach also reprogrammes the intestines, making them burn sugar faster, a study in diabetic and obese rats has shown. If the results, published today in Science1, hold true in humans, they could explain how gastric bypass surgery improves sugar control in people with diabetes. They could also lead to less invasive ways to produce the same effects. “This opens up the idea that we could take the most effective therapy we have for obesity and diabetes and come up with ways to do it without a scalpel,” says Randy Seeley, an obesity researcher at the University of Cincinnati in Ohio, who was not involved in the work. As rates of obesity and diabetes skyrocket in many countries, physicians and patients are turning to operations that reconfigure the digestive tract so that only a small part of the stomach is used. Such procedures are intended to allow people to feel full after smaller meals, reducing the drive to consume extra calories. But clinical trials in recent years have shown that they can also reduce blood sugar levels in diabetics, even before weight is lost2, 3. “We have to think about this surgery differently,” says Seeley. “It’s not just changing the plumbing, it’s altering how the gut handles glucose.” © 2013 Nature Publishing Group,

Keyword: Obesity
Link ID: 18412 - Posted: 07.27.2013

Researchers have found in mice that supporting cells in the inner ear, once thought to serve only a structural role, can actively help repair damaged sensory hair cells, the functional cells that turn vibrations into the electrical signals that the brain recognizes as sound. The study in the July 25, 2013 online edition of the Journal of Clinical Investigation reveals the rescuing act that supporting cells and a chemical they produce called heat shock protein 70 (HSP70) appear to play in protecting damaged hair cells from death. Finding a way to jumpstart this process in supporting cells offers a potential pathway to prevent hearing loss caused by certain drugs, and possibly by exposure to excess noise. The study was led by scientists at the National Institutes of Health. Over half a million Americans experience hearing loss every year from ototoxic drugs — drugs that can damage hair cells in the inner ear. These include some antibiotics and the chemotherapy drug cisplatin. In addition, about 15 percent of Americans between the ages of 20 and 69 have noise-induced hearing loss, which also results from damage to the sensory hair cells. Once destroyed or damaged by noise or drugs, sensory hair cells in the inner ears of humans don’t grow back or self-repair, unlike the sensory hair cells of other animals such as birds and amphibians. This has made exploring potential pathways to protect or regrow hair cells in humans a major focus of hearing research.

Keyword: Hearing; Glia
Link ID: 18411 - Posted: 07.27.2013

By Dina Fine Maron All eyes were on Perry Cohen when he froze at the microphone. His voice failed him. He couldn’t read his notes. Eventually, the once-powerful Parkinson’s disease speaker had to be helped off the stage halfway through his speech. That was in February 2012, but the memory of that day is emblazoned in his mind. “It was the adrenaline and the pressure of speaking — it drained all the dopamine out,” Cohen says, referring to the brain chemical that is found lacking in the neurodegenerative disorder. “That’s why my symptoms got worse.” When Cohen learned he had Parkinson’s disease 17 years ago his symptoms were subtle. In the past couple years, however, the deterioration of his nervous system has become increasingly obvious, ultimately threatening to silence one of the most prominent voices in the Parkinson’s patient community. Cohen is now first in line to try a novel treatment he hopes will halt or even reverse the symptoms of his Parkinson’s disease. Two months ago he became the inaugural patient to undergo a gene therapy treatment led by the National Institutes of Health. The trial attempts to devise an intervention for Parkinson’s disease at the root of the problem: protecting dopamine in the brain. Researchers in this trial are attempting to surgically deliver a gene into the body that will make a natural protein to protect dopaminergic neurons, the brain cells attacked by the disease. To date no Parkinson’s treatment is geared toward reversing the progression of Parkinson’s disease. © 2013 Scientific American

Keyword: Parkinsons; Genes & Behavior
Link ID: 18410 - Posted: 07.27.2013

Silk has walked straight off the runway and into the lab. According to a new study published in the Journal of Clinical Investigation, silk implants placed in the brain of laboratory animals and designed to release a specific chemical, adenosine, may help stop the progression of epilepsy. The research was supported by the National Institute of Neurological Disorders and Stroke (NINDS) and the National Institute of Biomedical Imaging and Bioengineering (NIBIB), which are part of the National Institutes of Health. The epilepsies are a group of neurological disorders associated with recurring seizures that tend to become more frequent and severe over time. Adenosine decreases neuronal excitability and helps stop seizures. Earlier studies have suggested abnormally low levels of adenosine may be linked to epilepsy. Rebecca L. Williams-Karnesky, Ph.D. and her colleagues from Legacy Research Institute, Portland, Ore., Oregon Health and Sciences University (OHSU), Portland, and Tufts University, Boston, looked at long-term effects of an adenosine-releasing silk-implant therapy in rats and examined the role of adenosine in causing epigenetic changes that may be associated with the development of epilepsy. The investigators argue that adenosine’s beneficial effects are due to epigenetic modifications (chemical reactions that change the way genes are turned on or off without altering the DNA code, the letters that make up our genetic background). Specifically, these changes happen when a molecule known as a methyl group blocks a portion of DNA, affecting which genes are accessible and can be turned on. If methyl groups have been taken away (demethylated), genes are more likely to turn on.

Keyword: Epilepsy
Link ID: 18409 - Posted: 07.27.2013

Researchers in Canada and Ireland have discovered that blood pressure drugs, known as ACE inhibitors, can improve brain function while slowing down the onset of dementia. ACE inhibitors, known by names such as ramipril and perindopril, have been already been shown in previous studies to delay the onset of dementia. What the medical community didn’t know was that these drugs may also enhance cognitive function. The study, published in the British Medical Journal, concludes that the use of ACE inhibitors could become useful in the management of dementia. The study examined 361 patients, all of whom had been diagnosed with Alzheimer’s, vascular dementia (triggered by lack of blood supply to the brain) or a mix of the two. Many Alzheimer's patients suffer dementia, which can affect memory, thinking, reasoning, planning and the ability to speak. Eighty-five of the patients were already taking the ACE inhibitors while the rest were not. Researchers also separately tested 30 patients, put on the drugs for the first time, for changes in their brain function. The average age was 77 and participants were followed for one year. © CBC 2013

Keyword: Alzheimers; Learning & Memory
Link ID: 18408 - Posted: 07.27.2013

by Carl Zimmer Inside each of us is a miniature version of ourselves. The Canadian neurologist Wilder Penfield discovered this little person in the 1930s, when he opened up the skulls of his patients to perform brain surgery. He would sometimes apply a little electric jolt to different spots on the surface of the brain and ask his patients–still conscious–to tell him if they felt anything. Sometimes their tongues tingled. Other times their hand twitched. Penfield drew a map of these responses. He ended up with a surreal portrait of the human body stretched out across the surface of the brain. In a 1950 book, he offered a map of this so-called homunculus. For brain surgeons, Penfield’s map was a practical boon, helping them plan out their surgeries. But for scientists interested in more basic questions about the brain, it was downright fascinating. It revealed that the brain organized the sensory information coming from the skin into a body-like form. There were differences between the homunculus and the human body, of course. It was as if the face had been removed from the head and moved just out of reach. The area that each body part took up in the brain wasn’t proportional to its actual size. The lips and index finger were gigantic, for instance, while the forearm barely took up less space than the tongue. That difference in our brains is reflected in our nerve endings. Our fingertips are far more sensitive than our backs. We simply don’t need to make fine discriminations with our backs. But we use our hands for all sorts of things–like picking up objects or using tools–that demand that sort of sensory power.

Keyword: Pain & Touch
Link ID: 18407 - Posted: 07.25.2013

By Susan Milius When a peacock fans out the iridescent splendor of his train, more than half the time the peahen he’s displaying for isn’t even looking at him. That’s the finding of the first eye-tracking study of birds. In more than 200 short clips recorded by eye-tracking cameras, four peahens spent less than one-third of the time actually looking directly at a displaying peacock, says evolutionary biologist Jessica Yorzinski of Purdue University in West Lafayette, Ind. When peahens did bother to watch the shimmering male, they mostly looked at the lower zone of his train feathers. The feathers’ upper zone of ornaments may intrigue human observers, but big eyespots there garnered less than 5 percent of the female’s time, Yorzinski and her colleagues report July 24 in the Journal of Experimental Biology. These data come from a system that coauthor Jason Babcock of Positive Science, an eye-tracking company in New York City, engineered to fit peahens. Small plastic helmets hold two cameras that send information to a backpack of equipment, which wirelessly transmits information to a computer. One infrared head camera focuses on an eye, tracking pupil movements. A second camera points ahead, giving the broad bird’s-eye view. The rig weighs about 25 grams and takes some getting used to. If a peahen with no experience of helmets gets the full rig, Yorzinski says, “she just droops her head to the ground.” Adding bits of technology gradually, however, let Yorzinski accustom peahens to walking around, and even mating, while cameraed up. © Society for Science & the Public 2000 - 2013

Keyword: Sexual Behavior; Vision
Link ID: 18406 - Posted: 07.25.2013

Avoiding temptation works better than relying on willpower alone, a study of brain activity finds. "Struggles with self-control pervade daily life and characterize an array of dysfunctional behaviours, including addiction, overeating, overspending and procrastination," Molly Crockett, a postdoctoral fellow at University College London, and her co-authors said in today's issue of the journal Neuron. "Our research suggests that the most effective way to beat temptations is to avoid facing them in the first place," she said in a release. In the experiment, researchers studied 58 healthy heterosexual males in Cambridge and 20 in Amsterdam. Investigators used functional MRI as part of the study of self-control to explore the neural mechanisms involved. At the beginning of the trial, participants were shown a series of 400 images of women in lingerie or swimwear and were asked to rank them on a scale of zero to 10 on how enjoyable they were. Each man's preferences were then used to present small, short-term rewards or a large reward after a delay. Small rewards were mildly enjoyable erotic pictures and large rewards were extremely enjoyable ones. (The scientists said they could not use money, for example, since subjects could only reap the rewards of money once they left the lab. Food rewards like juice could interfere with the MRI readings.) © CBC 2013

Keyword: Attention; Obesity
Link ID: 18405 - Posted: 07.25.2013

By Simon Makin One common complaint about psychiatry is its subjective nature: it lacks definitive tests for many diseases. So the idea of diagnosing disorders using only brain scans holds great appeal. A paper published recently in PLOS ONE describes such a system, although it was presented only as an initial proof of concept. News reports, however, trumpeted the advent of “objective” psychiatric diagnoses. The paper used data from several earlier studies, in which researchers outlined key brain regions in MRI scans of people with bipolar disorder, ADHD, schizophrenia or Tourette's syndrome; people with low or high risk of developing major depressive disorder; and a healthy group. The scans were also labeled with the disorder or depression risk level of the original study participant. In the new study, scientists divided the scans randomly into two sets, one to build the diagnostic system and the other to test it. Their software then grouped the scans in the first set by the shape of various regions. Each group was labeled with the most common diagnosis found within it. During testing, the system analyzed the shapes of brain regions in each test scan and assigned it to the group it most resembled. The scientists checked its work by comparing the new labels on the test scans with the original clinical diagnoses. They repeated the procedure several times with different randomly generated sets. When the system chose between two disorders or one ailment and a clean bill of health, its accuracy was nearly perfect. When deciding among three alternatives, it did much worse. © 2013 Scientific American

Keyword: Brain imaging; Schizophrenia
Link ID: 18404 - Posted: 07.23.2013

Recycling is not only good for the environment, it’s good for the brain. A study using rat cells indicates that quickly clearing out defective proteins in the brain may prevent loss of brain cells. Results of a study in Nature Chemical Biology suggest that the speed at which damaged proteins are cleared from neurons may affect cell survival and may explain why some cells are targeted for death in neurodegenerative disorders. The research was supported by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health. One of the mysteries surrounding neurodegenerative diseases is why some nerve cells are marked for destruction whereas their neighbors are spared. It is especially puzzling because the protein thought to be responsible for cell death is found throughout the brain in many of these diseases, yet only certain brain areas or cell types are affected. In Huntington’s disease and many other neurodegenerative disorders, proteins that are misfolded (have abnormal shapes), accumulate inside and around neurons and are thought to damage and kill nearby brain cells. Normally, cells sense the presence of malformed proteins and clear them away before they do any damage. This is regulated by a process called proteostasis, which the cell uses to control protein levels and quality. In the study, Andrey S. Tsvetkov and his colleagues showed that differences in the rate of proteostasis may be the clue to understanding why certain nerve cells die in Huntington’s, a genetic brain disorder that leads to uncontrolled movements and death.

Keyword: Huntingtons
Link ID: 18403 - Posted: 07.23.2013

By Scicurious We all know we should get more sleep, we’re just not very good at it. In fact, we’re so BAD at it that 28.3% of us (as of 2007, anyway) got less than 6 hours of sleep per night. Really, are we surprised? After all, there are kids that wake up in the night, stress that keeps us awake, always more things to do, multiple jobs, and only so many hours in the day. But that lack of sleep can have some not so great effects on our bodies. It decreases things like cognitive performance, increases anxiety, and…it’s not good for our waistlines. Sleep loss is associated with higher caloric intake, when you can’t sleep you eat. But does this increased caloric intake translate to weight gain? The biggest positive point of this study on sleep restriction was how LARGE it was. When doing human studies that are not large scale surveys (which usually involve phone calls or mail in or online and therefore are less expensive) it costs a LOT of money to bring some people in to the lab to do nothing but hang out and sleep for a week, especially if you are watching for things like food intake (and controlling what they eat). I’m very pleased that they got these numbers, 225 people! The authors took these 225 people, and brought them into the lab. They got two baseline nights (to see how much they naturally slept), 5 sleep restriction nights, and then another 2 recovery nights. But unfortunately, they did not balance the control and sleep restriction, where they were restricted down to FOUR HOURS a night of sleep (ick). They only had 27 controls out of all of these (people allowed to sleep fully all the nights of the study), the rest were sleep restriction. I have to wonder why they did it this way. While the two original nights and the two recovery nights could in theory serve as a partial control, I don’t think that those would work. After all, if most people are slightly sleep restricted, the original two nights will be recovery as well, and both sets of recovery nights may not be representative of optimal sleep. © 2013 Scientific American

Keyword: Sleep; Obesity
Link ID: 18402 - Posted: 07.23.2013

By Michelle Warwicker BBC Nature Individual wild wolves can be recognised by just their howls with 100% accuracy, a study has shown. The team from Nottingham Trent University, UK, developed a computer program to analyse the vocal signatures of eastern grey wolves. Wolves roam huge home ranges, making it difficult for conservationists to track them visually. But the technology could provide a way for experts to monitor individual wolves by sound alone. "Wolves howl a lot in the wild," said PhD student Holly Root-Gutteridge, who led the research. "Now we can be sure... exactly which wolf it is that's howling." The team's findings are published in the journal Bioacoustics. Wolves use their distinctive calls to protect territory from rivals and to call to other pack members. "They enjoy it as a group activity," said Ms Root-Gutteridge, "When you get a chorus howl going they all join in." The team's computer program is unique because it analyses both volume (or amplitude) and pitch (or frequency) of wolf howls, whereas previously scientists had only examined the animals' pitch. "Think of [pitch] as the note the wolf is singing," explained Ms Root-Gutteridge. "What we've added now is the amplitude - or volume - which is basically how loud it's singing at different times." "It's a bit like language: If you put the stress in different places you form a different sound." BBC © 2013

Keyword: Language; Evolution
Link ID: 18401 - Posted: 07.23.2013

By Rebecca Morelle Science reporter, BBC World Service Scientists have found further evidence that dolphins call each other by "name". Research has revealed that the marine mammals use a unique whistle to identify each other. A team from the University of St Andrews in Scotland found that when the animals hear their own call played back to them, they respond. The study is published in the Proceedings of the National Academy of Sciences. Dr Vincent Janik, from the university's Sea Mammal Research Unit, said: "(Dolphins) live in this three-dimensional environment, offshore without any kind of landmarks and they need to stay together as a group. "These animals live in an environment where they need a very efficient system to stay in touch." It had been-long suspected that dolphins use distinctive whistles in much the same way that humans use names. Previous research found that these calls were used frequently, and dolphins in the same groups were able to learn and copy the unusual sounds. But this is the first time that the animals response to being addressed by their "name" has been studied. To investigate, researchers recorded a group of wild bottlenose dolphins, capturing each animal's signature sound. BBC © 2013

Keyword: Language; Evolution
Link ID: 18400 - Posted: 07.23.2013

by Virginia Morell The next time your dog digs a hole in the backyard after watching you garden, don't punish him. He's just imitating you. A new study reveals that our canine pals are capable of copying our behavior as long as 10 minutes after it's happened. The ability is considered mentally demanding and, until this discovery, something that only humans and apes were known to do. Scientists first discovered that dogs are excellent at imitating their owners in 2006. Or at least, one dog had the talent: Philip, a 4-year-old Belgian Tervuren working with József Topál, a behavioral ethologist at the Hungarian Academy of Sciences in Budapest. Topál adapted the method (called "Do as I do") that Keith and Catherine Hayes developed in the 1950s for teaching an infant chimpanzee to copy their actions. Philip was already a trained assistant dog for his disabled owner and readily followed Topál's commands. First, Topál told him to stay, and then commanded "Do as I do." The researcher then performed a simple action, such as jumping in place, barking, putting an object in a box, or carrying it to Philip's owner. Next, Topál ordered, "Do it!", and Philip responded by matching the scientist's actions. The experiment was designed to explore dog's imitative abilities, not to measure how long Philip's memory lasted; but his owner used Philip's skill to teach him how to do new, useful behaviors, such as fetching objects or putting things away. Despite Philip's abilities, "nobody really cared, or saw that it could be useful for investigating how dogs learn or see their world," says Ádám Miklósi, a behavioral ethologist at Eötvös Loránd University in Budapest who was part of Topál's team. And in 2009, another team concluded that dogs were only able to correctly imitate if there was no more than a 5-second delay between watching the action and repeating it. With such a short retention span, dogs' vaunted imitation skills seemed useless. © 2010 American Association for the Advancement of Science

Keyword: Learning & Memory; Evolution
Link ID: 18399 - Posted: 07.23.2013

Steve Connor Author Biography The prospect of restoring the sight of blind people with stem-cell transplants has come a step closer with a study showing that it is possible to grow the light-sensitive cells of the eye in a dish with the help of an artificial retina, scientists said. For the first time, researchers have not only grown the photoreceptors of the eye in the laboratory from stem cells but transplanted them into eyes of blind mice where the cells have become fully integrated into the complex retinal tissue. So far the scientists have been unable to show any improvement in the vision of the blind mice – but they are confident that this will soon be possible in further experiments, which should enable them to move to the first clinical trials on patients within five years. Professor Robin Ali of University College London, who led the research at the Institute of Ophthalmology and Moorfields Eye Hospital, said that the technique could lead to stem cell transplants for improving the vision of thousands of people with degenerative eye disorders caused by the progressive loss of photosensitive cells. “The breakthrough here is that we’ve demonstrated we can transplant photoreceptors derived from embryonic stem cells into adult mice. It paves the way to a human clinical trial because now we have a clear route map of how to do it,” Professor Ali said. The loss of photosensitive cells, the rods and cones of the retina, is a leading cause of sight loss in a number of degenerative eye diseases, such as age-related macular degeneration, retinitis pigmentosa and diabetes-related blindness. © independent.co.uk

Keyword: Vision; Stem Cells
Link ID: 18398 - Posted: 07.23.2013

The author of a new six-step plan for Canadian doctors treating concussion patients warns that many people are unaware you don't need to hit your head to get a concussion. Dr. Charles Tator of the neurosurgery division at the University of Toronto wrote in Monday's Canadian Medical Association And for doctors and other trained health professionals in remote regions who have the responsibility for diagnosing concussions, Tator's primer summarizes how to detect and assess the injury. Concussions are the most common traumatic brain injury, often occurring during vehicle collisions, work activities, sports, recreation and falls in seniors. Females may be more prone to concussion than males, said Dr. Charles Tator.Females may be more prone to concussion than males, said Dr. Charles Tator. (CBC) It's now clear concussion can occur without direct impact to the head. For instance, a blow to the chest can cause a whiplash effect on the brain that jiggles the organ. Everyone who is involved in sports should be aware of the importance of recognizing concussions, he said. The most frequent symptoms are headache, dizziness, nausea and imbalance. Only one symptom is needed for the diagnosis. "The importance of accurate and timely recognition and management stems from the consequences of misdiagnosis or faulty management that can lead to major disability or death, in both the short and long term," Tator wrote. © CBC 2013

Keyword: Brain Injury/Concussion
Link ID: 18397 - Posted: 07.23.2013

By Melinda Wenner Moyer Many studies over the past decade have pointed to pesticides as a potential cause of Parkinson's disease, a neurodegenerative condition that impairs motor function and afflicts a million Americans. Yet scientists have not had a good idea of how these chemicals harm the brain. A recent study suggests a possible answer: pesticides may inhibit a biochemical pathway that normally protects dopaminergic neurons, the brain cells selectively attacked by the disease. Preliminary research also indicates that this pathway plays a role in Parkinson's even when pesticides are not involved, providing an exciting new target for drug development. Past studies have shown that a pesticide called benomyl, which lingers in the environment despite having been banned in the U.S. in 2001 because of health concerns, inhibits the chemical activity of aldehyde dehydrogenase (ALDH) in the liver. Researchers at the University of California, Los Angeles, U.C. Berkeley, the California Institute of Technology and the Greater Los Angeles Veterans Affairs Medical Center wondered whether the pesticide might also affect levels of ALDH in the brain. ALDH's job is to break down DOPAL, a naturally forming toxic chemical, rendering it harmless. To find out, the researchers exposed different types of human brain cells—and, later, whole zebra fish—to benomyl. They found that it “killed almost half of the dopamine neurons while leaving all other neurons tested intact,” according to lead author and U.C.L.A. neurologist Jeff Bronstein. When they zeroed in on the affected cells, they confirmed that the benomyl was indeed inhibiting the activity of ALDH, which in turn spurred the toxic accumulation of DOPAL. Interestingly, when the scientists lowered DOPAL levels using a different technique, benomyl did not harm the dopamine neurons, a finding that suggests that the pesticide kills these neurons specifically because it allows DOPAL to build up. © 2013 Scientific American,

Keyword: Parkinsons; Neurotoxins
Link ID: 18396 - Posted: 07.20.2013