Chapter 8. General Principles of Sensory Processing, Touch, and Pain

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By Meredith Wadman When people die from overdoses of opioids, whether prescription pain medications or street drugs, it is the suppression of breathing that almost always kills them. The drugs act on neuronal receptors to dull pain, but those in the brain stem also control breathing. When activated, they can signal respiration to slow, and then stop. The results are well-known: an epidemic of deaths—about 64,000 people in the United States alone last year. Countering this lethal side effect without losing opioids' potent pain relief is a challenge that has enticed drug developers for years. Now, for the first time, the U.S. Food and Drug Administration (FDA) in Silver Spring, Maryland, is considering whether to approve an opioid that is as effective as morphine at relieving pain and poses less risk of depressing breathing. Trevena, a firm based in Chesterbrook, Pennsylvania, announced on 2 November that it has submitted oliceridine, an intravenous opioid meant for use in hospitalized patients, to FDA for marketing approval. The drug, which would be marketed under the name Olinvo, is the most advanced of what scientists predict will be a growing crop of pain-relieving "biased agonists"—so called because, in binding a key opioid receptor in the central nervous system, they nudge it into a conformation that promotes a signaling cascade that kills pain over one that suppresses breathing. And in a paper out this week in Cell, a veteran opioid researcher and her colleagues unveil new biased opioid agonists that could surpass oliceridine, though they haven't been tested in people yet. "There are many groups creating [such] biased agonists. And one of them is going to get it right," says Bryan Roth, a molecular pharmacologist at the University of North Carolina in Chapel Hill. "To have a drug you can't die of an overdose with would be a huge lifesaver for tens of thousands of people every year." © 2017 American Association for the Advancement of Science.

Keyword: Drug Abuse; Pain & Touch
Link ID: 24337 - Posted: 11.17.2017

Jon Hamilton The goal is simple: a drug that can relieve chronic pain without causing addiction. But achieving that goal has proved difficult, says Edward Bilsky, a pharmacologist who serves as the provost and chief academic officer at Pacific Northwest University of Health Sciences in Yakima, Wash. "We know a lot more about pain and addiction than we used to," says Bilsky, "But it's been hard to get a practical drug." Bilsky is moderating a panel on pain, addiction and opioid abuse at the Society for Neuroscience meeting in Washington, D.C., this week. Brain scientists have become increasingly interested in pain and addiction as opioid use has increased. About 2 million people in the U.S. now abuse opioids, according to the Centers for Disease Control and Prevention. But at least 25 million people suffer from chronic pain, according to an analysis by the National Institutes of Health. That means they have experienced daily pain for more than three months. The question is how to cut opioid abuse without hurting people who live with pain. And brain scientists think they are getting closer to an answer. One approach is to find drugs that decrease pain without engaging the brain's pleasure and reward circuits the way opioids do, Bilsky says. So far, these drugs have been hampered by dangerous side effects or proved less effective than opioids at reducing pain. But substances related to snail venom look promising, Bilsky says. © 2017 npr

Keyword: Pain & Touch
Link ID: 24321 - Posted: 11.13.2017

By Roni Dengler The bills of even newly hatched ducks might be as sensitive as our hands, as touch sensors in their beaks are as abundant as those in our fingertips and palms. That’s the take-away of new research published today in the Proceedings of the National Academy of Sciences that describes the origins of touchiness in the common duck’s quacker. Researchers knew that duck bills can sense light touch but have muted responsiveness to temperature. This comes in handy (or bill-y) since the birds forage for food in cold, murky bottom waters. Now, researchers find the sensors duck bills use to perceive touch work even before hatching. That likely helps young ducklings scavenge for food alongside adults soon after birth. In keeping with the need to feel for food, the ducks have more nerve cells to relay touch signals than chickens, which rely on eyesight to find sustenance, they report. That means different developmental programs are at work in ducks and chickens, which could help scientists uncover how touch evolved. Because the duck’s touch sensors are similar to mammals’ and their bills aren’t covered in fur, the authors suggest embryonic duck bills might be a better model than standard laboratory rodents to study touch sensation as it applies to us relatively hairless humans. © 2017 American Association for the Advancement of Science

Keyword: Pain & Touch; Development of the Brain
Link ID: 24298 - Posted: 11.07.2017

By JANE E. BRODY After two hourlong sessions focused first on body awareness and then on movement retraining at the Feldenkrais Institute of New York, I understood what it meant to experience an incredible lightness of being. Having, temporarily at least, released the muscle tension that aggravates my back and hip pain, I felt like I was walking on air. I had long refrained from writing about this method of countering pain because I thought it was some sort of New Age gobbledygook with no scientific basis. Boy, was I wrong! The Feldenkrais method is one of several increasingly popular movement techniques, similar to the Alexander technique, that attempt to better integrate the connections between mind and body. By becoming aware of how one’s body interacts with its surroundings and learning how to behave in less stressful ways, it becomes possible to relinquish habitual movement patterns that cause or contribute to chronic pain. The method was developed by Moshe Feldenkrais, an Israeli physicist, mechanical engineer and expert in martial arts, after a knee injury threatened to leave him unable to walk. Relying on his expert knowledge of gravity and the mechanics of motion, he developed exercises to help teach the body easier, more efficient ways to move. I went to the institute at the urging of Cathryn Jakobson Ramin, author of the recently published book “Crooked” that details the nature and results of virtually every current approach to treating back pain, a problem that has plagued me on and off (now mostly on) for decades. Having benefited from Feldenkrais lessons herself, Ms. Ramin had good reason to believe they would help me.

Keyword: Pain & Touch; Attention
Link ID: 24259 - Posted: 10.30.2017

Bill Chappell It has the power to save lives by targeting opioid overdoses — something that kills more than 140 Americans every day. And now Narcan, the nasal spray that can pull a drug user back from an overdose, is being carried by all of Walgreens' more than 8,000 pharmacies. "By stocking Narcan in all our pharmacies, we are making it easier for families and caregivers to help their loved ones by having it on hand in case it is needed," said Walgreens vice president Rick Gates. The pharmacy chain is making the move as America struggles to respond to an opioid epidemic that President Trump is declaring a national emergency on Thursday, hoping to fight the opioid crisis that has struck families and communities from rural areas to cities. Calling the Walgreens move "an important milestone," Seamus Mulligan, CEO of Narcan maker Adapt Pharma, said that letting people get the medicine "without an individual prescription in 45 states is critical in combating this crisis." In recent years, both Walgreens, the nation's No. 2 pharmacy chain, and CVS, the No. 1 chain, have moved to widen access to Narcan and other products that contain naloxone, a fast-acting overdose antidote. As of last month, CVS reportedly offered prescription-free naloxone in 43 states. The chain has said that its pharmacies "in most communities have naloxone on hand and can dispense it the same day or ordered for the next business day." © 2017 npr

Keyword: Drug Abuse
Link ID: 24249 - Posted: 10.27.2017

As a ballet dancer in a former life, countless rehearsal hours in pointe shoes once landed me in a podiatrist’s office with a particularly inflamed ingrown toenail. To my surprise – and the doctor’s – a typical injection of local anesthesia did nothing to numb the searing pain as his knife dug into my big toe. It was not until a second full injection made my toe the size of a golf ball that I became blissfully unaware of the pain. Was my hair color to blame? It is, after all, a rumor every redhead has heard: we feel more pain and need more painkillers. A look at the published research suggests that the genes that determine my hair color may play a role, but the science itself is murky. What makes a redhead? Our luster-filled locks derive from a pair of mutated genes. For most people, hair color is determined by the melanocortin-1 receptor, or MC1R gene that leads to the production of a brown-black melanin pigment called eumelanin. The more eumelanin created by this gene, the darker and blacker the hair. Most redheads have a recessive version of the MC1R gene caused by the pairing of three possible mutant alleles. The resulting gene expression shuts off eumelanin production, shifting the dominant pigment to the reddish-toned pheomelanin. McGill University behavioral neuroscientist Jeffrey Mogil examined the gene as part of his research on the perception and inhibition of pain. “The purpose of this MC1R gene is to produce dark pigments. If it works, it does, and if it doesn’t, it produces pigment that isn’t dark like it’s supposed to be. So, it really is a dysfunction,” he said.

Keyword: Pain & Touch; Genes & Behavior
Link ID: 24248 - Posted: 10.27.2017

By Amina Zafar, CBC News The soothing power of touch eases both physical pain and the sting of hurt feelings, say researchers — a finding that may be increasingly important in our social-media-driven world. When someone hurts an arm, they may brace and rub it to make it feel better. In the past 20 years, scientists have discovered that our hairy skin has cells that respond to a stroking touch. It's a trait we share with other mammals. Now psychologists in England say their work shows, for the first time, that a gentle touch can be a buffer against social rejection, too. In an experiment described in this week's issue of Scientific Reports, researchers recruited 84 healthy women and told them they were going to play a game of Cyberball, an online ball-tossing game. What the women didn't know was that their "opponents" were computer-generated avatars. Participants were told they could throw to anyone they wished, and they believed everyone would play fairly. When participants reported feeling excluded by the other "players," receiving a slow-paced stroke reduced hurt feelings from the perceived rudeness compared with a faster stroke. The study builds on previous ones showing that receiving touch from loved ones after a physical injury is supportive. "In our lab, it's tiny in effect, but the fact that it is significantly, systematically so across many participants is important," said the study's senior author, Katerina Fotopoulou, an associate professor of psychology at University College London ©2017 CBC/Radio-Canada.

Keyword: Pain & Touch
Link ID: 24222 - Posted: 10.20.2017

Expensive medicines can seem to create worse side-effects than cheaper alternatives, suggests a new study that looked at the "nocebo" effect of drugs. The opposite of the placebo effect — perceived improvement when no active medicine is given — nocebo is the perception of negative side-effects from a benign "medication" in a blind trial. These findings about nocebo effects could help improve the design of clinical trials that test new medications, said Dr. Luana Colloca, who wrote a journal commentary about the study. "The main information for patients is that they should be aware that sometimes our brain … reacts as a result of our beliefs and expectations," said Colloca, a pain researcher at University of Maryland School of Nursing. fMRI Researchers used a functional MRI scanner to identify areas along the spinal cord that became activated during the nocebo effect. (Alexandra Tinnermann and Tim Dretzler/University Medical Center Hamburg-Eppendorf) The study, published recently in the journal Science, focused on the pain perceptions of patients who were treated with creams they believed had anti-itch properties but actually contained no active ingredients. Researchers in Germany studied 49 people, randomly assigning some to receive a "cheap" cream and others to receive an "expensive" cream. Those in the expensive group received cream packaged in a colourful box labelled Solestan Creme. The others received cream packaged in a drab box labelled with the more generic sounding name Imotadil-LeniPharma Creme. ©2017 CBC/Radio-Canada.

Keyword: Pain & Touch
Link ID: 24218 - Posted: 10.19.2017

Laura Sanders Hydrogen peroxide, a molecule produced by cells under duress, may be a common danger signal, helping to alert animals to potential harm and send them scurrying. New details from planarian flatworms of how this process works may deepen scientists’ understanding of how people detect pain, and may ultimately point to better ways to curb it. “Being able to get a big-picture view of how these systems are built and what they’re cuing in on is always really helpful,” says biologist Paul Garrity of Brandeis University in Waltham, Mass. And by finding cellular similarities among planarians, fruit flies and people, the new study, published online October 16 in Nature Neuroscience, provides hints about how this threat-detecting system might have operated hundreds of millions of years ago. The results center on a protein called TRPA1, a well-known pain detector in people. Embedded in the outside of cells, TRPA1 helps many different animals detect (and ultimately escape) harmful chemicals, physical injuries and extreme temperatures. In humans, mutations in the TRPA1 gene can cause syndromes marked by intense pain. But scientists have puzzled over TRPA1’s seemingly inconsistent behavior in different animals. In Caenorhabditis elegans worms, for instance, the protein is activated by cold. But in other animals such as mosquitoes, TRPA1 is activated by heat. “The more people started looking at activation of TRPA1 in different species, the more the puzzle became complicated,” says study coauthor Marco Gallio of Northwestern University in Evanston, Ill. © Society for Science & the Public 2000 - 2017.

Keyword: Pain & Touch; Evolution
Link ID: 24211 - Posted: 10.18.2017

By Michael Price Expensive medications tend to make us feel better, even when they’re no different than cheap generics. But they can also make us feel worse, according to a new study. Researchers have found that we’re more likely to experience negative side effects when we take a drug we think is pricier—a flip side of the placebo effect known as the “nocebo” effect. The work could help doctors decide whether to recommend brand-name or generic drugs depending on each patient’s expectations. In the study, researchers asked 49 people to test out a purported anti-itch cream that, in reality, contained no active ingredient. Some got “Solestan® Creme,” a fake brand name in a sleek blue box designed to look like other expensive brands on the market. Others received “Imotadil-LeniPharma Creme”—another fake, this time housed in a chintzier orange box resembling those typically used for generic drugs. “I put a lot of effort into making the designs convincing,” says study leader Alexandra Tinnermann, a neuroscientist at University Medical Center Hamburg-Eppendorf in Germany. The researchers rubbed one of the two creams on the volunteers’ forearms and waited a few minutes for it soak in. They told the participants that the cream could cause increased sensitivity to pain—a known side effect of real medications called hyperalgesia. Then the scientists affixed a small device to the volunteers’ arms that delivered a brief flash of heat up to about 45°C (or 113°F). © 2017 American Association for the Advancement of Science.

Keyword: Pain & Touch
Link ID: 24154 - Posted: 10.06.2017

By JANE E. BRODY If you’ve never had a migraine, I have two things to say to you: 1) You’re damn lucky. 2) You can’t begin to imagine how awful they are. I had migraines – three times a month, each lasting three days — starting from age 11 and finally ending at menopause. Although my migraines were not nearly as bad as those that afflict many other people, they took a toll on my work, family life and recreation. Atypically, they were not accompanied by nausea or neck pain, nor did I always have to retreat to a dark, soundless room and lie motionless until they abated. But they were not just “bad headaches” — the pain was life-disrupting, forcing me to remain as still as possible. Despite being the seventh leading cause of time spent disabled worldwide, migraine “has received relatively little attention as a major public health issue,” Dr. Andrew Charles, a California neurologist, wrote recently in The New England Journal of Medicine. It can begin in childhood, becoming more common in adolescence and peaking in prevalence at ages 35 to 39. It afflicts two to three times more women than men, and one woman in 25 has chronic migraines on more than 15 days a month. But while the focus has long been on head pain, migraines are not just pains in the head. They are a body-wide disorder that recent research has shown results from “an abnormal state of the nervous system involving multiple parts of the brain,” said Dr. Charles, of the U.C.L.A. Goldberg Migraine Program at the David Geffen School of Medicine in Los Angeles. He told me he hoped the journal article would educate practicing physicians, who learn little about migraines in medical school. Before it was possible to study brain function through a functional M.R.I. or PET scan, migraines were thought to be caused by swollen, throbbing blood vessels in the scalp, usually – though not always — affecting one side of the head. This classic migraine symptom prompted the use of medications that narrow blood vessels, drugs that help only some patients and are not safe for people with underlying heart disease. © 2017 The New York Times Company

Keyword: Pain & Touch
Link ID: 24072 - Posted: 09.18.2017

Mariah Quintanilla Kenneth Catania knows just how much it hurts to be zapped by an electric eel. For the first time, the biologist at Vanderbilt University in Nashville has measured the strength of a defensive electrical attack on a real-life potential predator — himself. Catania placed his arm in a tank with a 40-centimeter-long electric eel (relatively small as eels go) and determined, in amperes, the electrical current that flowed into him when the eel struck. At its peak, the current reached 40 to 50 milliamperes in his arm, he reports online September 14 in Current Biology. This zap was painful enough to cause him to jerk his hand from the tank during each trial. “If you’ve ever been on a farm and touched an electric fence, it’s pretty similar to that,” he says. This is Catania’s latest study in a body of research analyzing the intricacies of an electric eel’s behavior. The way electric eels have been described by biologists in the past has been fairly primitive, says Jason Gallant, a biologist who heads the Michigan State University Electric Fish Lab in East Lansing who was not involved in the study. Catania’s work reveals that “what the electric eel is doing is taking the electric ability that it has and using that to its absolute advantage in a very sophisticated, deliberate way,” he says. Electric eels use electric current to navigate, communicate and hunt for small prey. But when faced with a large land-based predator, eels will launch themselves from the water and electrify the animal with a touch of the head. |© Society for Science & the Public 2000 - 2017.

Keyword: Aggression
Link ID: 24068 - Posted: 09.15.2017

By JANE E. BRODY Many years ago I was plagued with debilitating headaches associated with a number of seemingly unrelated activities that included cooking for company and sewing drapes for the house. I thought I might be allergic to natural gas or certain fabrics until one day I realized that I tensed my facial muscles when I concentrated intently on a project. The cure was surprisingly simple: I became aware of how my body was reacting and changed it through self-induced behavior modification. I consciously relaxed my muscles whenever I focused on a task that could precipitate a tension-induced headache. Fast-forward about five decades: Now it was my back that ached when I hurriedly cooked even a simple meal. And once again, after months of pain, I realized that I was transferring stress to the muscles of my back and had to learn to relax them, and to allow more time to complete a project to mitigate the stress. Happy to report, I recently prepared dinner for eight with nary a pain. I don’t mean to suggest that every ache and pain can be cured by self-awareness and changing one’s behavior. But recent research has demonstrated that the mind – along with other nonpharmacological remedies — can be powerful medicine to relieve many kinds of chronic or recurrent pains, especially low back pain. As Dr. James Campbell, a neurosurgeon and pain specialist, put it, “The best treatment for pain is right under our noses.” He suggests not “catastrophizing” – not assuming that the pain represents something disastrous that keeps you from leading the life you’ve chosen. Acute pain is nature’s warning signal that something is wrong that should be attended to. Chronic pain, however, is no longer a useful warning signal, yet it can lead to perpetual suffering if people remain afraid of it, the doctor said. © 2017 The New York Times Company

Keyword: Pain & Touch
Link ID: 24053 - Posted: 09.11.2017

By Matt Reynolds Putting on a brave face won’t fool this algorithm. A new system that rates how much pain someone is in just by looking at their face could help doctors decide how to treat patients. By examining tiny facial expressions and calibrating the system to each person, it provides a level of objectivity in an area where that’s normally hard to come by. “These metrics might be useful in determining real pain from faked pain,” says Jeffrey Cohn at the University of Pittsburgh in the US. The system could make the difference between prescribing potentially addictive painkillers and catching out a faker. Objectively measuring pain levels is a tricky task, says Dianbo Liu, who created the system with his colleagues at the Massachusetts Institute of Technology. People experience and express pain differently, so a doctor’s estimate of a patient’s pain can often differ from a self-reported pain score. In an attempt to introduce some objectivity, Liu and his team trained an algorithm on videos of people wincing and grimacing in pain. Each video consisted of a person with shoulder pain, who had been asked to perform a different movement and then rate their pain levels. The result was an algorithm that can use subtle differences in facial expressions to inform a guess about how a given person is feeling. Certain parts of the face are particularly revealing, says Liu. Large amounts of movement around the nose and mouth tended to suggest higher self-reported pain scores. © Copyright New Scientist Ltd.

Keyword: Pain & Touch; Emotions
Link ID: 24026 - Posted: 09.02.2017

Andrea Hsu Dan Fabbio was 25 and working on a master's degree in music education when he stopped being able to hear music in stereo. Music no longer felt the same to him. When he was diagnosed with a brain tumor, he immediately worried about cancer. Fortunately, his tumor was benign. Unfortunately, it was located in a part of the brain known to be active when people listen to and make music. Fabbio told his surgeon that music was the most important thing is his life. It was his passion as well as his profession. His surgeon understood. He's someone whose passion has been mapping the brain so he can help patients retain as much function as possible. Dr. Web Pilcher, chair of the Department of Neurosurgery at the University of Rochester Medical Center, and his colleague Brad Mahon, a cognitive neuroscientist, had developed a brain mapping program. Since 2011, they've used the program to treat all kinds of patients with brain tumors: mathematicians, lawyers, a bus driver, a furniture maker. Fabbio was their first musician. The idea behind the program is to learn as much as possible about the patient's life and the patient's brain before surgery to minimize damage to it during the procedure. "Removing a tumor from the brain can have significant consequences depending upon its location," Pilcher says. "Both the tumor itself and the operation to remove it can damage tissue and disrupt communication between different parts of the brain." © 2017 npr

Keyword: Hearing; Pain & Touch
Link ID: 24002 - Posted: 08.26.2017

Laurel Hamers Scientists have traced the sensation of itch to a place you can’t scratch. The discomfort of a mosquito bite or an allergic reaction activates itch-sensitive nerve cells in the spinal cord. Those neurons talk to a structure near the base of the brain called the parabrachial nucleus, researchers report in the Aug. 18 Science. It’s a region that’s known to receive information about other sensations, such as pain and taste. The discovery gets researchers one step closer to finding out where itch signals ultimately end up. “The parabrachial nucleus is just the first relay center for [itch signals] going into the brain,” says study coauthor Yan-Gang Sun, a neuroscientist at the Chinese Academy of Sciences in Shanghai. Understanding the way these signals are processed by the brain could someday provide relief for people with chronic itch, Sun says. While the temporary itchiness of a bug bite is annoying, longer term, “uncontrollable scratching behavior can cause serious skin damage.” Previous studies have looked at the way an itch registers on the skin or how neurons convey those sensations to the spinal cord. But how those signals travel to the brain has been a trickier question, and this research is a “major step” toward answering it, says Zhou-Feng Chen, director of the Center for the Study of Itch at Washington University School of Medicine in St. Louis. |© Society for Science & the Public 2000 - 2017.

Keyword: Pain & Touch
Link ID: 23972 - Posted: 08.18.2017

Researchers from the National Institutes of Health have identified a class of sensory neurons (nerve cells that electrically send and receive messages between the body and brain) that can be activated by stimuli as precise as the pulling of a single hair. Understanding basic mechanisms underlying these different types of responses will be an important step toward the rational design of new approaches to pain therapy. The findings were published in the journal Neuron. “Scientists know that distinct types of neurons detect different types of sensations, such as touch, heat, cold, pain, pressure, and vibration,” noted Alexander Chesler, Ph.D., lead author of the study and principal investigator with the National Center for Complementary and Integrative Health’s (NCCIH) Division of Intramural Research (DIR). “But they know more about neurons involved with temperature and touch than those underlying mechanical pain, like anatomical pain related to specific postures or activities.” In this study, Chesler and his colleagues used a novel strategy that combined functional imaging (which measures neuronal activity), recordings of electrical activity in the brain, and genetics to see how neurons respond to various stimuli. The scientists focused on a class of sensory neurons that express a gene called Calca, as these neurons have a long history in pain research. The scientists applied various stimuli to the hairy skin of mice cheeks, including gentle mechanical stimuli (air puff, stroking, and brushing), “high-threshold” mechanical stimuli (hair pulling and skin pinching), and temperature stimulation. They found that the target neurons belong to two broad categories, both of which were insensitive to gentle stimulation. The first was a well-known type of pain fiber—a polymodal nociceptor—that responds to a host of high intensity stimuli such as heat and pinching. The second was a unique and previously unknown type of neuron that responded robustly to hair pulling. They called this previously undescribed class of high-threshold mechanoreceptors (HTMRs) “circ-HTMRs,” due to the unusual nerve terminals these neurons made in skin. They observed that the endings of the fibers made lasso-like structures around the base of each hair follicle.

Keyword: Pain & Touch
Link ID: 23970 - Posted: 08.17.2017

By DAVID C. ROBERTS Five years ago, I still lived a double life. I was 35, looking out over the Gulf of Thailand and a few weathered beach tenders. Inside, where dark suits filled the conference room, I could feel the eyes of my fellow diplomats. No doubt they were wondering why I was sitting on my briefcase. I joked to no one in particular “My nuclear codes,” trying to deflect awkwardness. The case actually concealed an orthotic sitting cushion that muffled the pain in my lower back; without it, silent shrieking was all I heard. Or maybe they had noticed I was the only one sweating. The air-conditioning tempered the tropical heat, but it was no match for the corset heat wrap that lay discreetly under my tailored suit. Over the previous decade I had become adept at hiding the unexplained pain that racked my back and joints. To all appearances, I was a fit 6-foot-3 man with an easy gait. No one in that conference room knew my suit pants disguised a lace-up ankle brace and a strap velcroed around my left knee. Nor did they know that during breaks I would sneak back to my hotel room where my wife, an artist who moonlighted as my one-person pit crew, waited to press my quadratus lumborum muscle back into submission. I lasted through that meeting as I had through countless others. But in the months that followed, sitting and walking became increasingly difficult. I started to stand during meetings, avoid plane travel, and take motorcycle taxis to go just a couple of buildings’ distance. Eventually, I let the doctors at the embassy in on my secret. They deemed me unfit for work and medevac’ed me from Bangkok back to the United States for treatment. I left quickly, without awkward explanations or goodbyes. © 2017 The New York Times Company

Keyword: Pain & Touch
Link ID: 23908 - Posted: 08.02.2017

Ashlie Stevens Ah, the brain freeze — the signature pain of summer experienced by anyone who has eaten an ice cream cone with too much enthusiasm or slurped down a slushie a little too quickly. But have you ever stopped mid-freeze to think about why our bodies react like this? Well, researchers who study pain have, and some, like Dr. Kris Rau of the University of Louisville in Kentucky, say it's a good way to understand the basics of how we process damaging stimuli. But first, a lesson in terminology. "There's a scientific medical term for ice cream headaches which is sphenopalatine ganglion neuralgia," Rau says. Try breaking that out at your next ice cream social. Anyway, to understand how brain freeze happens, it helps to think of your body and brain as a big computer where everything is hooked together. In this case, you see an ice cream truck. You get some ice cream. And then your brain gives you the go-ahead and you dive face-first into a double-scoop of mint chocolate chip. "Now on the roof of your mouth there are a lot of little blood vessels, capillaries," Rau says. "And there's a lot of nerve fibers called nociceptors that detect painful or noxious stimuli." The rush of cold causes those vessels to constrict. "And when that happens, it happens so quickly that all of those little pain fibers in the roof of your mouth — they interpret that as being a painful stimulus," Rau says. A message is then shot up to your brain via the trigeminal nerve, one of the major nerves of the facial area. The brain itself doesn't have any pain sensing fibers, but its covering — called the meninges — does. © 2017 npr

Keyword: Pain & Touch
Link ID: 23901 - Posted: 08.01.2017

By Natalie Grover (Reuters) - A handful of drugmakers are taking their first steps toward developing marijuana-based painkillers, alternatives to opioids that have led to widespread abuse and caused the U.S. health regulator to ask for a withdrawal of a popular drug this month. The cannabis plant has been used for decades to manage pain and there are increasingly sophisticated marijuana products available across 29 U.S. states, as well as in the District of Columbia, where medical marijuana is legal. There are no U.S. Food and Drug Administration (FDA)-approved painkillers derived from marijuana, but companies such as Axim Biotechnologies Inc, Nemus Bioscience Inc and Intec Pharma Ltd have drugs in various stages of development. The companies are targeting the more than 100 million Americans who suffer from chronic pain, and are dependent on opioid painkillers such as Vicodin, or addicted to street opiates including heroin. Opioid overdose, which claimed celebrities including Prince and Heath Ledger as victims, contributed to more than 33,000 deaths in 2015, according to the Centers for Disease Control and Prevention. Earlier this month, the FDA asked Endo International Plc to withdraw its Opana ER painkiller from the market, the first time the agency has called for the removal of an opioid painkiller for public health reasons. The FDA concluded that the drug's benefits no longer outweighed its risks. Multiple studies have shown that pro-medical marijuana states have reported fewer opiate deaths and there are no deaths related to marijuana overdose on record.(http://reut.rs/2r74Sbe) © 2017 Scientific American

Keyword: Pain & Touch; Drug Abuse
Link ID: 23774 - Posted: 06.26.2017