By HARRIET BROWN On a sweltering evening in July of last year, I sat at the end of my daughter Kitty's bed, holding a milkshake made from a cup of Häagen-Dazs coffee ice cream and a cup of whole milk. Kitty (the pet name we've used since she was a baby) shivered, wrapped in a thick quilt. "Here's your milkshake," I said, aiming for a tone that was friendly but firm, a tone that would make her reach for the glass and begin drinking. Six-hundred ninety calories — that's what this milkshake represented to me. But to Kitty it was the object of her deepest fear and loathing. "You're trying to make me fat," she said in a high-pitched, distorted voice that made the hairs on the back of my neck stand up. She rocked, clutching her stomach, chanting over and over: "I'm a fat pig. I'm so fat." That summer, Kitty was 14. She was 4-foot-11 and weighed 71 pounds. I could see the angles and curves of each bone under her skin. Her hair, once shiny, was lank and falling out in clumps. Her breath carried the odor of ketosis, the sour smell of the starving body digesting itself. I kept my voice neutral. "You need to drink the milkshake," I repeated. She lifted her head, and for a second I saw the 2-year-old Kitty, her mouth quirked in a half-smile, her dark eyes full of humor. It was enough to keep me from shrieking: Just drink the damn milkshake! Enough to keep me sitting on the end of the bed for the next two hours, talking in a low voice, lifting the straw to her lips over and over. The milkshake had long since melted when she swallowed the last of it, curled up in bed and closed her eyes. Her gaunt face stayed tense even in sleep. Copyright 2006 The New York Times Company

Keyword: Anorexia & Bulimia
Link ID: 9668 - Posted: 06.24.2010

Rachel Nowak COULD the end of sign language for deaf children be in sight? A spate of new studies has shown that profoundly deaf babies who receive cochlear implants in their first year of life develop language and speech skills remarkably close to those of hearing children. Many of the children even learn to sing passably well and function almost flawlessly in the hearing world. These findings may sound like a triumph to audiologists and the hearing parents of deaf babies. But they have done little to convince those in the deaf community who maintain that it is unethical to give deaf babies cochlear implants, which bypass damaged areas of the ear and stimulate the auditory nerve directly. "The idea of operating on a healthy baby makes us all recoil," says Harlan Lane, a psycholinguist at Northeastern University in Boston. "Deaf people argue that they use a different language, and with it comes a different culture, but there is certainly nothing wrong with them that needs fixing with a surgeon's scalpel. We should listen." Ever since cochlear implants became commercially available 20 years ago they have been seen as a threat to the culture and language of those born profoundly deaf. The fiercest opposition has been to their use in children, who could otherwise grow up proficient in sign language. Until recently there was no good evidence that implants routinely improved children's chances of developing normal speech and language, raising fears that those fitted with implants would be stuck in a no-man's land - part of neither the hearing world nor the deaf one. © Copyright Reed Business Information Ltd

Keyword: Hearing; Language
Link ID: 9667 - Posted: 06.24.2010

When a faulty protein wreaks havoc in cells and causes disease, researchers are usually quick to point the finger at a wayward gene. Now scientists are learning that some neurodegenerative diseases can develop even though a gene is perfectly normal. The diseases can be caused when the genetic instructions contained in the gene are not executed properly, leading to a lethal buildup of malformed proteins in brain cells. The new studies by Howard Hughes Medical Institute (HHMI) investigator Susan L. Ackerman and colleagues at The Jackson Laboratory point to a novel mechanism behind the buildup of the toxic sludge that accumulates in neurons. Researchers have long known that neurodegenerative disorders can be caused by the gradual yet persistent accumulation of misfolded proteins in neurons that eventually triggers cell death. But this new mechanism points to errors in executing the genetic instructions, which are distinct from known causes of neurodegenerative diseases, such as Alzheimer's and Huntington's diseases. HHMI investigator Susan L. Ackerman and her colleagues reported their findings in an advance online publication of the journal Nature on August 13, 2006. Ackerman's group collaborated on the studies with co-author Paul Schimmel at The Scripps Research Institute. The researchers made their discovery by studying mice with a mutation called sticky (sti). Although named for the sticky appearance of their fur, the mice harbor much more serious problems beneath their unkempt coats: poor muscle control, or ataxia, due to death of Purkinje cells in a region of the brain called the cerebellum. © 2006 Howard Hughes Medical Institute.

Keyword: Movement Disorders; Genes & Behavior
Link ID: 9666 - Posted: 06.24.2010

Older schizophrenia drugs may be as effective as the new generation of medications, experts have suggested. A Manchester University study shows patients respond just as well, and perhaps better, to the older ones. The Archives of General Psychiatry findings run contrary to the widely held view that newer and dearer drugs are safer and more effective. But critics say the newer drugs are better and preferred by patients because they have fewer side effects. The new UK results back similar work by US investigators who recently suggested it might be better to switch back to prescribing the older drugs to cut healthcare costs. The NHS funded the latest work to assess whether the bigger price tag of newer "atypical" antipsychotics was offset by improvements in patients' quality of life or reductions in the use of health and social care services. Atypical antipsychotics, which include risperidone, quetiapine, clozapine and olanzapine, cost at least 10 times more than their predecessors. The Manchester team, along with colleagues from the University of Cambridge, Institute of Psychiatry and Imperial College London, studied 227 schizophrenia patients for whom a change in drug treatment was being considered because of ineffectiveness or harmful side effects. Experienced doctors decided which type of antipsychotic - newer or older - would be best for each patient. The patients were assessed before and 12, 26 and 52 weeks after their drugs were switched, using measurements of quality of life, symptoms, side effects, and satisfaction with the drug. Overall, the newer atypical drugs showed no advantage in side effects or effectiveness. (C)BBC

Keyword: Schizophrenia
Link ID: 9665 - Posted: 11.25.2006

"Old dogs" may really find it hard to learn new tricks, a study of how memories form has suggested. University of Oxford scientists say that adults may find learning more difficult than children because their brains store memories differently. The study, in the journal Neuron, looked at nerve cell activity - the basis of learning and memory - in rats. Experts said younger brains may learn things more easily, but older brains may store information more efficiently. The researchers, backed by the Medical Research Council and the Wellcome Trust looked at the nerve cell processes in young and old rats. Nerve cells communicate by sending signals though synapses, junctions between the cells. But some synapses are "silent" and are not activated when chemical signals are passed between cells. The team used highly detailed laser imaging, which looked at images one micron wide - a 100th the width of a human hair, to look at how synapses behave. They focused on electrical activity and the movement of molecules called calcium ions. They found that silent synapses are more prevalent in young brains, and are called on when new memories are laid down. When this happens, key receptors - which detect stimuli - are called to the surface of the cell, transforming it into an active synapse. In older brains, there were fewer silent synapses - which the researchers believe is because they have been used up. (C)BBC

Keyword: Learning & Memory; Alzheimers
Link ID: 9664 - Posted: 11.25.2006

By GARDINER HARRIS Their rooms are a mess, their trophies line the walls, and both have profiles on MySpace.com. Stephen and Jacob Meszaros seem like typical teenagers until their mother offers a glimpse into the family’s medicine cabinet. "We always debate meds," said Billy Igafo-Te'o. Mr. Igafo-Te'O is the father of Michael Igafo-Te'O, 12, who takes four drugs and has damaged their home so often that they no longer repair it. Bottles of psychiatric medications fill the shelves. Stephen, 15, takes the antidepressants Zoloft and Desyrel for depression, the anticonvulsant Lamictal to moderate his moods and the stimulant Focalin XR to improve concentration. Jacob, 14, takes Focalin XR for concentration, the anticonvulsant Depakote to moderate his moods, the antipsychotic Risperdal to reduce anger and the antihypertensive Catapres to induce sleep. Over the last three years, each boy has been prescribed 28 different psychiatric drugs. “Sometimes, when you look at all the drugs they’ve taken, you wonder, ‘Wow, did I really do this to my kids?’ ” said their mother, Tricia Kehoe of Sharpsville, Pa. “But I’ve seen them without the meds, and there’s a major difference.” There is little doubt that some psychiatric medicines, taken by themselves, work well in children. But a growing number of children and teenagers in the United States are taking not just a single drug for discrete psychiatric difficulties but combinations of powerful and even life-threatening medications to treat a dizzying array of problems. Copyright 2006 The New York Times Company

Keyword: Depression; Schizophrenia
Link ID: 9663 - Posted: 06.24.2010

Having a word stuck on the tip of the tongue is enough to activate an unusual condition in which some people perceive words as having different tastes, according to a new study. When people with the inherited condition, called synesthesia, looked at pictures of objects that come up infrequently in conversation, they perceived a taste before they could think of the word. Some researchers believe synesthesia is an extreme version of what happens in everyone's mind. If so, the result suggests that all abstract thoughts are associated with specific perceptions, says neuropsychologist Julia Simner of the University of Edinburgh, co-author of the report. "The extent to which abstract thought is truly abstract--that's really what the question is." Simner and her colleague Jamie Ward of University College London tested six synesthetes by showing them pictures of 96 uncommon objects such as a gazebo, sextant, catamaran, artichoke or castanets. Out of 550 trials in total, Simner and Ward induced 89 tip-of-the-tongue states. In 17 of these "um, um" moments, the synesthete reported perceiving a taste while still trying to conjure the word. In short, the word's meaning alone elicited the taste. To confirm that these reports were truthful the researchers called the participants out of the blue a year later and retested them. The synesthetes consistently associated the same tastes with the same words, the researchers report in the November 22 Nature. © 1996-2006 Scientific American, Inc.

Keyword: Chemical Senses (Smell & Taste); Language
Link ID: 9662 - Posted: 06.24.2010

Why people think that rivals are better looking than they really are IF YOU have ever sat alone in a bar, depressed by how good-looking everybody else seems to be, take comfort—it may be evolution playing a trick on you. A study just published in Evolution and Human Behavior by Sarah Hill, a psychologist at the University of Texas, Austin, shows that people of both sexes reckon the sexual competition they face is stronger than it really is. She thinks that is useful: it makes people try harder to attract or keep a mate. Dr Hill showed heterosexual men and women photographs of people. She asked them to rate both how attractive those of their own sex would be to the opposite sex, and how attractive the members of the opposite sex were. She then compared the scores for the former with the scores for the latter, seen from the other side. Men thought that the men they were shown were more attractive to women than they really were, and women thought the same of the women. Dr Hill had predicted this outcome, thanks to error-management theory—the idea that when people (or, indeed, other animals) make errors of judgment, they tend to make the error that is least costly. The notion was first proposed by Martie Haselton and David Buss, two of Dr Hill's colleagues, to explain a puzzling quirk in male psychology. © The Economist Newspaper Limited 2006.

Keyword: Sexual Behavior; Evolution
Link ID: 9661 - Posted: 06.24.2010

Conventional wisdom holds that myelin, the sheet of fat that coats a neuron's axon — a long fiber that conducts the neuron's electrical impulses — is akin to the wrapping around an electrical wire, protecting and fostering efficient signaling. But the research of UCLA neurology professor George Bartzokis, M.D., has already shown that myelin problems are implicated in diseases that afflict both young and old — from schizophrenia to Alzheimer's. Now, in a report published in the journal Biological Psychiatry and available online, Bartzokis argues that the miles of myelin coating in our brain are the key "evolutionary change that defines our uniqueness as a species" and, further, may also be the cause of "our unique vulnerability to highly prevalent neuropsychiatric disorders." The paper argues that viewing the brain as a myelin-dependent "Internet" may be key to developing new and novel treatments against disease and aid in assessing the efficacy of currently available treatments, including the use of nicotine (delivered by a patch, not smoking), which may enhance the growth and maintenance of myelin. Myelin, argues Bartzokis, who directs the UCLA Memory Disorders and Alzheimer's Disease Clinic, is "a recent invention of evolution. Vertebrates have it; invertebrates don't. And humans have more than any other species." Bartzokis studied the reported effects of cholinergic treatments, using drugs that are known to improve a neuron's synaptic signaling in people who suffer diseases like Alzheimer's. Furthermore, he notes, some clinical and epidemiological data suggest that such treatments may modify or even delay these diseases.

Keyword: Alzheimers; Glia
Link ID: 9660 - Posted: 06.24.2010

Mutations in a key brain protein known to underlie a form of Parkinson's disease (PD) wreaks its damage by stunting the normal growth and branching of neurons, researchers have found. They have pinpointed the malfunction of the protein made by mutant forms of the gene called LRRK2 and how it affects neurons, ultimately leading to their death. The loss of dopamine-producing neurons is central to the pathology of PD, and loss of connections among such neurons is an early feature of the PD disease process. The researchers, Asa Abeliovich and colleagues at Columbia University, said their findings could lead to animal models for studying the form of PD and ultimately to new treatments for the disease. They reported their findings in the November 22, 2006, issue of the journal Neuron, published by Cell Press. The researchers launched their study of LRRK2 because other scientists had identified mutations in the gene in an inherited form of PD that mimics the clinical and pathological features of the common sporadic form of the disease. LRRK2 stands for "leucine-rich repeat kinase-2," which means that the LRRK2 protein is an enzyme called a kinase--a biochemical switch that activates other proteins by attaching a molecule called a phosphate to them. In their experiments, when the researchers generated mutant forms of the enzyme, they discovered that the mutants showed higher-than-normal enzymatic kinase activity compared to the normal version. When they introduced the mutant forms into cultures of neurons, they saw a reduction in the growth and branching of the neurons.

Keyword: Parkinsons
Link ID: 9659 - Posted: 11.25.2006

Rachel Crellin Until three years ago teacher Barbara Cullen was fit and healthy, spending most of her leisure time outdoors pursuing various hobbies which included a passion for surfing. Suddenly out of the blue she started getting severe headaches. As they first began around Christmas time she wondered if it was due to yuletide excess, but the headaches became more and more severe. All her husband Fred could do was to sit and watch. "To actually watch somebody holding their head in their hands and then getting down on their knees on the floor and literally shaking, you think this is not a normal headache," he said. "I initially assumed this is something that she's going to die from, she's going to have a brain haemhorrage." Barbara was getting the headaches up to eight times every day - the pain was so intense that she began to contemplate taking her own life. "It's excruciating and it's there all the time, it doesn't go away. And being in constant pain you are dragged down, it's a vicious circle, because I can't sleep, I'm constantly tired. You have to take morphine-based painkillers and you become disorientated and it would be quite easy to just take a few extra and just get rid of the pain once and for all." The National is one of Britain's leading brain hospitals where around 100 consultants treat everything from head injuries to Parkinson's disease, paralysis to epilepsy. Some doctors here are the only specialist of their kind in the country and for many patients the National is their last chance. At the National Barbara's headaches were diagnosed as cluster headaches. The pain they cause is thought to be ten times worse than childbirth - they have been nicknamed suicide headaches because of the excruciating pain - like being stabbed in the head with a needle. Barbara's only chance of getting rid of the pain was to have an operation to implant an occipital nerve stimulator into the back of her head. (C)BBC

Keyword: Pain & Touch
Link ID: 9658 - Posted: 11.22.2006

By Sara Goudarzi From male killer whales that ride the dorsal fin of another male to female bonobos that rub their genitals together, the animal kingdom tolerates all kinds of lifestyles. A first-ever museum display, "Against Nature?," which opened last month at the University of Oslo's Natural History Museum in Norway, presents 51 species of animals exhibiting homosexuality. "Homosexuality has been observed in more than 1,500 species, and the phenomenon has been well described for 500 of them," said Petter Bockman, project coordinator of the exhibition. The idea, however, is rarely discussed in the scientific community and is often dismissed as unnatural because it doesn't appear to benefit the larger cause of species continuation. "I think to some extent people don't think it's important because we went through all this time period in sociobiology where everything had to be tied to reproduction and reproductive success," said Linda Wolfe, who heads the Department of Anthropology at East Carolina University. "If it doesn't have [something to do] with reproduction it's not important." © 2006 MSNBC.com

Keyword: Sexual Behavior
Link ID: 9657 - Posted: 06.24.2010

By Ker Than It might be a treasured value in many human cultures, but monogamy is rare in the animal kingdom at large. Of the roughly 5,000 species of mammals, only 3 to 5 percent are known to form lifelong pair bonds. This select group includes beavers, otters, wolves, some bats and foxes and a few hoofed animals. And even the creatures that do pair and mate for life occasionally have flings on the side. Some, like the wolf, waste little time finding a new mate if their old one dies or can no longer sexually perform. Staying faithful can be a struggle for most animals. For one, males are hardwired to spread their genes and females try to seek the best dad for their young. Also, monogamy is costly because it requires an individual to place their entire reproductive investment on the fitness of their mate. Putting all their eggs in one basket means there’s a lot of pressure on each animal to pick the perfect mate, which, as humans knows, can be tricky. Because of recent revelations from animal studies, scientists now distinguish between three different types of monogamy: Sexual monogamy is the practice of having sex only with one mate at a time. Social monogamy is when animals form pairs to mate and raise offspring but still have flings — or "extra-pair copulations" in science lingo — on the side. Genetic monogamy is used when DNA tests can confirm that a female's offspring were sired by only one father. © 2006 MSNBC.com

Keyword: Sexual Behavior
Link ID: 9656 - Posted: 06.24.2010

The bright coloration of some birds is a classic example of an animal advertising its high quality to potential mates. Carotenoids are the pigment in red, orange and yellow skin (and carrots), but they are also powerful antioxidants that boost the immune system. Only healthy male birds can afford to maintain a costly display of color by diverting resources away from the immune system, the theory goes. The male must therefore have good genes, and that's why a flashy male attracts mates. In the mating game testosterone plays a similar role to carotenoids. The hormone makes male birds strut and croon but weakens their immune systems, and researchers knew that variations in testosterone levels between birds and seasons tend to match up with variations in the brightness of colors. "There should be a connection between these two signaling systems," says ecologist Julio Blas of the University of Saskatchewan in Saskatoon, Canada. Blas and his colleagues in Spain and Canada reasoned that high testosterone should increase the amount of carotenoids in the blood. If a male is healthy, they hypothesized, he would not need the surplus pigment to bolster his immune system, so his skin and beak will become saturated with color instead. To test the idea the group implanted capsules of testosterone under the skin of 13 red-legged partridges. These doped birds had 20 percent more carotenoids in their blood after the treatment, apparently because they absorbed more of the compounds from their food, whereas untreated birds showed no change. © 1996-2006 Scientific American, Inc.

Keyword: Sexual Behavior; Neuroimmunology
Link ID: 9655 - Posted: 06.24.2010

Making memories seems like a difficult proposition given that our synapses are constantly in action. These connections between nerve cells in our brain, which are regularly passing chemical messages back and forth, also supposedly have our memories distributed across them. Yet, regardless of the perpetual exchange of molecules, our memories remain stable. According to a pair of researchers at the University of Utah, it is the presence of scaffolding proteins in the synapses that anchor our life lessons within the chaos of brain activity. Researchers have come to a consensus that on a timescale of hours to a few days synapses change chemically through one of two processes: long-term potentiation (LTP), the strengthening of a synapse; or long-term depression (LDP), the weakening of a synapse. There is debate, however, over what determines how this strength changes. One of the keys to the process appears to be the number of AMPA receptor proteins, which bind glutamate, an excitatory neurotransmitter that is believed to be involved in learning and memory. Researchers have observed AMPA traveling from the inside of a neuron to the downstream end of a synapse, but they remain uncertain as to whether the migration into and out of the synapse is the major component in determining synaptic strength. "There's a lot of data out there that actually measures over time how the strength of a synapse varies during LTP/LTD," says Paul Bressloff, a theoretical neuroscientist, who used a system of differential equations to model AMPA receptors' movements. "They know these things happen, and they make hypotheses about how things could fit together, but they don't do any quantitative study to see if it could really work. And that's what we've basically done." © 1996-2006 Scientific American, Inc.

Keyword: Learning & Memory
Link ID: 9654 - Posted: 06.24.2010

Lauran Neergaard, Associated Press — Woe to those who have a cold on Thursday. If you can't smell the roasting turkey, it just won't taste as good. And if you think the brussels sprouts are bitter, well, blame how many taste buds you were born with, not the chef. But never fear: Even after you're pleasantly stuffed from second helpings, there's a little spot deep in your brain that still gives a "Wow!" for pumpkin pie. How we taste is pretty complicated, an interaction of the tongue, the nose, psychological cues and exposure to different foods. But ultimately, we taste with our brains. "Why do we learn to like foods? When they're paired with something our brains are programmed to see as good," says Dr. Linda Bartoshuk of the University of Florida, a specialist in the genetics of human taste. Sorry, brains are programmed to want fat, probably an evolutionary hangover from times of scarcity. But what's necessary for survival isn't all the brain likes. University of Michigan researchers just uncovered that eating something tasty can spark brain cells that sense actual pleasure to start firing rapidly. More provocative, how intensely people sense different flavors seems to affect how healthy they are. © 2006 Discovery Communications Inc.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 9653 - Posted: 06.24.2010

Michael Hopkin You might be forgiven for thinking that fish have no personality. But according to biologists in Britain, not only do different trout have different characters, but these change as the fish experience life's highs and lows. Winning or losing a fight, or even watching fellow fish negotiate the perils and pitfalls of encountering strange new objects, influenced the future behaviour of rainbow trout (Oncorhynchus mykiss) studied in the lab. Researchers led by Lynne Sneddon, of the University of Liverpool, identified different 'personalities' in their fish by observing the boldness or shyness of individuals. Like people, some fish are very confident in the face of novelty or confrontation, whereas others are reticent and fearful. Sneddon and her team selected particularly bold and shy fish, and tested whether they changed their outlook depending on what life threw at them. They did this by arranging fish fights and watching to see how both the participants and observers responded to victories and defeats. The idea of animal personalities — known to researchers as 'behavioural syndromes' — has been around for a while. The idea aims to explain why some animals' behaviour is not always ideally suited to their circumstances. A male with a naturally aggressive temperament, for example, might be great at fighting off rivals, but might never get to mate because his heavy-handed seduction tactics scare off the ladies. ©2006 Nature Publishing Group

Keyword: Aggression; Stress
Link ID: 9652 - Posted: 06.24.2010

Roxanne Khamsi Hens with bigger fleshy crests on their heads get more sex and larger quantities of sperm from dominant male roosters, according to a new study. While many studies have shown that males with more visible ornamentation have a mating advantage, this is the first to show that large ornamental body parts can give female animals a mating advantage, the researchers claim. Charlie Cornwallis at the University of Oxford, UK, demonstrated that looks matter to male chickens by running a series of tests in which he presented each of them with pairs of hens. In the first part of the experiment, he and his colleagues covered the eye-catching red crests, known as “combs”, on the females’ heads with small hoods. This made it impossible for the male birds to size up the hens’ combs. As a result, in this part of the study, the males apparently picked their mate at random. Next, the researchers removed the hoods from the hens and repeated the tests. The team found that 80% of the time males went after the hen with a larger comb. The hens also wore a harness that held a plastic sack in place to collect the sperm males favoured them with. An analysis of collected samples revealed that large-combed hens received 50% more sperm from dominant males than their counterparts with relatively small combs per ejaculation. This is important because hens often compete for sex with dominant males, explains Cornwallis. © Copyright Reed Business Information Ltd

Keyword: Sexual Behavior
Link ID: 9651 - Posted: 06.24.2010

By Daniel Engber Last week, the New York Times reported that neuroscientists had gotten a look, for the first time, at the brains of devout Christians engaged in speaking in tongues. The test subjects believe that God takes possession of their minds and babbles through their mouths. And now, says the Times, "they have some neuroscience to back them up." The scientists compared the brain activity of their subjects in two conditions—first while they sang gospel songs, and second as they engaged in trancelike glossolalia replete with ecstatic bodily experiences. According to the research report, they found diminished activity in the dorsolateral prefrontal cortex, which normally lights up when you're doing something on purpose. "The amazing thing was how the images supported people's interpretations of what was happening," the study's lead author, Andrew Newberg, told the Times. If the test subjects said they were in a state of utter abandon, the pictures of their brains proved it. This certainly isn't the first time a new brain-imaging study has been touted as biological proof of a subjective experience. Recent Times articles have highlighted research into the neural structures associated with dread, hysteria, and even schadenfreude. Another study scanned subjects who had been hypnotized to show that their brain activity matched up with their altered perceptions. Last year, a British team fed subjects dessert while they were inside a functional MRI machine, and color-spattered slices of cortex revealed activation in the orbitofrontal pleasure centers. "Eating ice cream really does make you happy," began the article in The Guardian. 2006 Washington Post.Newsweek Interactive Co. LLC

Keyword: Brain imaging; Language
Link ID: 9650 - Posted: 06.24.2010

By HENRY FOUNTAIN A C. elegans Model of Nicotine-Dependent Behavior: Regulation by TRP-Family Channels (Cell)Researchers at the University of Michigan’s Life Sciences Institute have discovered that C. elegans can become dependent on nicotine. The tiny worm (above, magnified) is stimulated by the chemical, becomes tolerant of it with continued exposure and even gets withdrawal symptoms when it goes cold turkey. “Its behavioral responses parallel those observed in mammals,” said X. C. Shawn Xu, an assistant professor at the institute and an author of a paper in the journal Cell on the research. What’s more, Dr. Xu said, some of the same genes that mediate nicotine dependence in mammals are found in C. elegans, making it a genetic model as well as a behavioral one. So the tiny roundworm, already a laboratory workhorse that is central to studies of aging and other complex biological processes, may become a favored tool for nicotine research. “You can study mammals for nicotine dependence,” he said, “but it’s a lot easier to identify new functions of a gene in worms.” Previous research on C. elegans and nicotine had focused “on the muscle side,” Dr. Xu said, the biochemical pathways in muscle tissue that are activated by nicotine. Dr. Xu and his colleagues used very low concentrations of nicotine to examine the effect on the worm’s nervous system. (Low concentrations were important, he said, as too much nicotine “sort of O.D.’d the worm.”) Copyright 2006 The New York Times Company

Keyword: Drug Abuse
Link ID: 9649 - Posted: 06.24.2010