The molecules of pain How does the sensation of pain originate at the tips of our nerves? Some recently discovered molecules help to demystify these processes, as Michael Gross reports Ouch, that hurt! But it is a good thing, too. It is vital for our well-being that heat, wounds, and other potentially dangerous stimuli are reported immediately and drastically. For this reason we have nerve cells specialising in pain perception (nociceptors) in every millimetre of the skin. When an injury happens, they send electrical messages back to our central nervous system. That part of the process is fairly well understood. But what happens at the very tip of the nerve, at the cell membrane of the nociceptor, where this signal originates? Touch and pain have long been among the more poorly understood of our senses at a biochemical level. In recent years, however, scientists have found new molecules and mechanisms that could provide the answers to a whole host of questions. This web site is © copyright of Royal Society of Chemistry, 2000

Keyword: Pain & Touch
Link ID: 301 - Posted: 10.20.2001

HELEN PEARSON
A cell door that automatically snaps shut in milliseconds - this isn't the latest jailbreak deterrent but a fundamental part of our cells. Nearly 50 years after this microscopic marvel was discovered, researchers in New York have dissected the inner workings of the molecule responsible for generating the body's electrical impulses1. All excitable cells - such as those responsible for nerve signals, muscle contraction or the heart beat - depend on ion channels in the cell membrane. Triggered to open by a small voltage, such channels let through a flood of electrically charged ions, then promptly slam shut. The 'ball-and-chain' model was put forward in the 1970s to explain how this 'inactivation' occurs. The model suggested that a plug - or ball - swinging on a molecular 'chain' on the inside of the channel stops up the opening. Now Roderick MacKinnon and his colleagues at Rockefeller University in New York have found that the ball is more like a snake that sneaks inside the channel to block it. 1.Zhou, M., Morais-Cabral, J. H., Mann, S. & MacKinnon, R. Potassium channel receptor site for the inactivation gate and quaternary amine inhibitors. Nature 411, 657–661 (2001). © Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

Keyword: Neurotoxins
Link ID: 300 - Posted: 06.24.2010

Alzheimer's Disease Meets its Boxing Match Molecular Link between Alzheimer's and "Punch Drunk" Syndrome Found in Humans (Philadelphia, PA) - In the fight to link brain injuries and Alzheimer's Disease (AD) in humans, researchers at the University of Pennsylvania Medical Center have found a strong contender in the molecular weight category. Abnormal tau proteins, which form fibrous tangles in the brains of AD sufferers, are identical to the abnormal tau proteins found in patients with Dementia Pugilistica (DP), a memory disorder also known as Punch Drunk - or Boxer's - Syndrome. Researchers from Penn's Center for Neurodegenerative Disease Research (CNDR) compared the brains of people with a genetic history of AD and the brains of DP sufferers to discover if there is a molecular basis in humans for the notion that brain injuries could predispose a person to AD. Their findings, published in the June issue of the international neurology journal Acta Neuropathologica, suggest that lesions in the two disorders arise through similar means.

Keyword: Alzheimers
Link ID: 298 - Posted: 10.20.2001

Stem Cell Transplants The treatment of neurological ailments with transplant strategies that replace damaged or missing cells in the nervous system with a healthy crop is getting a push forward thanks to stem cells. These special cells can be derived from a variety of tissue types in the lab and persuaded to mass-produce fresh cell crops, according to studies. Even more encouraging, new findings in animals provide evidence that transplants of the cell batches survive and aid malfunctioning nervous systems. Add some grass seed, fertilizer and T.L.C. Voila! The once sparse and withered patch of lawn grows lush blades of green beauty. Neuroscientists have long dreamed of treating the battered brain similar to the way a landscaper treats a battered yard. But instead of grass seeds, they envisioned planting a fresh, healthy crop of cells. Instead of the earth, they envisioned placing these cells into the nervous system. And instead of replacing grass to boost curb appeal, they envisioned replacing damaged or missing cells to treat a variety of neurological ailments.

Keyword: Hormones & Behavior
Link ID: 297 - Posted: 10.20.2001

St. Louis, May 29, 2001 – Scientists have discovered that, unlike many other animals, humans have a reserve of oxygen in the brain. This buffer allows the brain to adapt to arduous situations without demanding a sharp increase in blood flow. "Our finding challenges the previously accepted idea that blood flow increases occur during tasks such as reading to raise oxygen levels in the brain," says study leader Mark A. Mintun, M.D. "That idea has been long assumed in brain imaging studies that attempt to understand how the human brain functions."

Keyword: Brain imaging
Link ID: 296 - Posted: 06.24.2010

HELEN PEARSON
Hey man, dig those spaced-out fish. Researchers have found a real space cadet - a mutant zebrafish that swims towards danger, rather than away from it1. Misplaced connections in its brain reveal that a single type of cell controls the urge to get away. Poke a baby zebrafish (Danio rerio) in the head and it normally flips and swims for its life. However, Michael Granato and colleagues at the University of Pennsylvania School of Medicine in Philadelphia searched for mutants whose escape response is up the spout. 1.Lorent, K., Liu, K. S., Fetcho, J. R. & Granato, M. The zebrafish space cadet gene controls axonal pathfinding of neurons that modulate fast turning movements. Development 128, 2131–2142 (2001). © Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

Keyword: Miscellaneous
Link ID: 295 - Posted: 06.24.2010

Dance of the Deceived Bees Imagine a driver asked to keep track of the number of buildings, signs, and lampposts whizzing by. Now ask that driver to tell a friend how far to go based on all those landmarks. That's exactly what honeybees do by dancing certain steps when they return to the hive. Now a new study shows that if the foragers get fooled, they will pass on the faulty directions to the rest of the hive--further evidence that eyesight is the apian odometer. Over the past several years, experiments have suggested that honeybees know how far they've gone by how much they've seen--and not, as many had thought, by the amount of energy expended on the trip. In a key experiment published in 2000, Mandyam Srinivasan and Shawu Zhang, neurobiologists at Australian National University in Canberra, Jürgen Tautz of the University of Würzburg in Germany, and their colleagues tested this idea by training bees to fly down tunnels with different patterns painted inside. They found that the bee danced longer than it should have after flying through a semicheckered tunnel that gave the bee the sense of moving past many, many objects. If the tunnel was lined with horizontal stripes, which had no vertical boundaries to signify an object being passed, the bee's dance was too short. --Elizabeth Pennisi Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Animal Communication
Link ID: 294 - Posted: 10.20.2001

Findings on brain chemistry may apply to other drugs as well
David Perlman, Chronicle Science Editor
Thursday, May 31, 2001 - It takes only a single dose of cocaine to create powerful changes in the brain's signaling system and trigger long-term addiction to the drug, a Bay Area research team has discovered. For the first time, the researchers have found the specific chemical pathways in the brain that surge into activity and turn laboratory mice into addicts when they are exposed to only a single cocaine dose. ©2001 San Francisco Chronicle Page A - 1

Keyword: Drug Abuse
Link ID: 293 - Posted: 10.20.2001

Accounting for Taste Genetics Could Provide Tools to Engineer New Flavors, Fragrances By Justin Gillis Washington Post Staff Writer LA JOLLA, Calif. -- A computer jockey named Michael Richards punches a keyboard to search a database of chemicals kept at a biotechnology company here. With a few keystrokes, he calls up one of the more unusual inventory lists in corporate America. "Harsh but sweet, floral-hay odor; sweet cherry-berry taste," reads the entry for a chemical called 1-acetyl-4-methyl benzene. "Fruity, floral, weak, vanilla-like odor and taste," says another entry, for 4-methoxybenzyl acetate. © 2001 The Washington Post Company

Keyword: Genes & Behavior
Link ID: 292 - Posted: 10.20.2001

tourette drug has unexpected effect A new study by Johns Hopkins Children's Center neurologists suggests that baclofen, a drug long thought to be effective in reducing the vocal and motor tics associated with Tourette syndrome, improves a patient's overall sense of well-being but does not significantly reduce tics. "One of our conclusions is that baclofen helps as a treatment for Tourette syndrome, but it appears to improve something other than tics," says pediatric neurologist Harvey Singer, M.D., the report's lead author. "We originally thought baclofen would diminish patients' vocal and muscular tics but found, instead, that it's more useful in making patients feel less impaired by their tics."

Keyword: Tourettes
Link ID: 291 - Posted: 10.20.2001

What Makes Tics Tick? Clues Found In Tourette Twins' Caudates For the first time, scientists have a neurobiological explanation for the variation in severity of tics in Tourette Syndrome. Researchers at the National Institute of Mental Health have traced such symptom differences to "supersensitivity" of certain neurotransmitter receptors in the brain structure responsible for carrying out automatic behaviors. They suggest that this dysfunction may underlie the compulsion to act out the sudden movements and vocalizations that characterize Tourette Syndrome, which affects about 100,000 Americans with its full-blown form and up to 0.5% of the population with milder symptoms. The researchers report on their findings in the August 30th issue of Science. In a brain imaging study of identical twins differently affected by the disorder, Daniel Weinberger, M.D., Steven Wolf, M.D., and colleagues in the NIMH Clinical Brain Disorders Branch found that binding to D2 dopamine receptors in the caudate nucleus was higher in the sibling with the more severe symptoms.

Keyword: Tourettes
Link ID: 290 - Posted: 10.20.2001

National Institute of Mental Health (NIMH) scientists have linked a gene variant that reduces dopamine activity in the prefrontal cortex to poorer performance and inefficient functioning of that brain region during working memory tasks, and to slightly increased risk for schizophrenia. The finding, which must still be confirmed by independent teams of investigators, emerged from an ongoing study of people with schizophrenia and their siblings. The study is among the first to suggest a mechanism by which a gene might confer susceptibility to a mental illness, say the researchers. Daniel Weinberger, M.D., Michael Egan, M.D., NIMH Clinical Brain Disorders Branch, and colleagues, report on their results in the May 29, 2001 Proceedings of the National Academy of Sciences.

Keyword: Schizophrenia
Link ID: 289 - Posted: 10.20.2001

ARLINGTON, Va., May 17, 2001 --- Biomedical engineers have used a mild electric field to control seizure-like activity in brain cells. The work hints at the possibility of controlling epilepsy in a similar way. In a recent issue of The Journal of Neuroscience, the researchers described a feedback system that monitors brain cells for seizure-like firing. When the firing begins, the system responds by applying a mild electric field, fewer than 50 millivolts per millimeter. When the erratic firing stops, the electric field shuts off.

Keyword: Epilepsy
Link ID: 288 - Posted: 10.20.2001

Scientists find solution to a mystery surrounding Alzheimer's, Huntington's and other neurological diseases Stanford researchers have found an answer to a long-standing mystery surrounding Huntington's, Alzheimer's, Parkinson's and other neurodegenerative diseases. Their discovery, published in the May 25 issue of the journal Science, focuses on one of the telltale signs of neurodegenerative illness: the mysterious buildup of defective proteins in and around nerve cells.

Keyword: Alzheimers
Link ID: 287 - Posted: 10.20.2001

Placebo effect downplayed by study Researchers discourage use of method Susan Okie, Washington Post Thursday, May 24, 2001 Surprising new evidence has called into question the existence of the "placebo effect," the widely accepted principle that people with various illnesses will often improve if given a dummy pill or a sham treatment. For a half-century, doctors have been taught that this phenomenon is partly responsible for the effectiveness of drugs. Researchers have taken it into account when testing new medicines. Biologists and psychologists have searched for its cause. Ethicists have even debated whether doctors could justifiably deceive patients to take advantage of it. The New York Times contributed to this report. ©2001 San Francisco Chronicle Page A - 9

Keyword: Pain & Touch
Link ID: 286 - Posted: 10.20.2001

Mushrooms aid total recall HELEN PEARSON Learning to love putrid pongs must take some nerve. But flies can learn smells even when critical nerve connections in their brains are blocked, researchers have found - although recalling the scents needs cells that are fully switched on1. The findings offer clues on how the mind keeps track of its memories. Flies like dung because of a brain nodule called the mushroom body. This knot of nerves is involved in learning and remembering smells - but whether it makes the memories, stores them or recalls them was unknown. 1.Keefe, A. D. & Szostak, J. W. Functional proteins from a random-sequence library. Nature 410, 715–718 (2001). © Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

Keyword: Learning & Memory
Link ID: 285 - Posted: 06.24.2010

Autism Linked to Developmental Gene Sifting through the DNA of hundreds of families, researchers have picked out a gene that may contribute to some cases of autism. Mutations in the gene, active during fetal development of the nervous system in frogs and probably humans, are linked to the severe language problems seen in some people with autism. Evidence from studies of twins suggests that genes play a central role in autism. No single gene causes the syndrome, but as many as 15 genes may interact to produce the symptoms, which include an inability to form emotional bonds with others, poor language skills, and repetitive behavior, such as rocking or head banging. --CAROLINE SEYDEL Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Autism
Link ID: 284 - Posted: 10.20.2001

TOM CLARKE
A well-timed one-two punch from viruses may cause multiple sclerosis (MS), researchers suggested at this week's American Society for Microbiology annual meeting in Orlando, Florida. MS occurs when the body's immune system turns against the protein myelin, which insulates our nerve cells. Viral infection of some form has long been suspected as the trigger for this auto-immune response, but no single virus has yet been linked to the disease. © Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

Keyword: Multiple Sclerosis
Link ID: 283 - Posted: 10.20.2001

Blind mice see TOM CLARKE There's more to vision than meets the eye. Although unable to see, mice lacking rods and cones in their retinas can tell day from night. And their pupils still respond to bright light1. These latest findings suggest that mammals' eyes contain another light-sensitive pigment not found in rods or cones. The pigment may regulate circadian rhythms that govern sleep patterns and other behaviours, such as eating, that are related to general light levels. Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

Keyword: Vision
Link ID: 282 - Posted: 10.20.2001

The more coffee people drink, according to some recent studies, the less likely they are to get Parkinson's disease. Now, researchers have shown in mice how caffeine may prevent the loss of dopamine, the critical brain chemical that is depleted by the disease. But they warn we're still a long way from prescribing double lattes to ward off Parkinson's. Last year, the results of a 30-year study from Honolulu showed a strong inverse relationship between caffeine consumption and Parkinson's in 8000 men, backing up earlier epidemiological observations. And converging lines of evidence suggested that caffeine interacts with receptors known to congregate in one of the brain regions damaged by Parkinson's disease. --CONSTANCE HOLDEN Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Drug Abuse
Link ID: 281 - Posted: 10.20.2001