A study led by scientists at The Scripps Research Institute (TSRI) has helped solve a long-standing mystery about the sense of touch.
The “gentle touch” sensations that convey the stroke of a finger, the fine texture of something grasped and the light pressure of a breeze on the skin are brought to us by nerves that often terminate against special skin cells called Merkel cells. These skin cells’ role in touch sensation has long been debated in the scientific community. The new study, however, suggests a dual-sensor system involving the Merkel cell and an associated nerve end in touch sensation.
Univ. of Utah and German biologists discovered how nerve cells recycle tiny bubbles or “vesicles” that send chemical nerve signals from one cell to the next. The process is much faster and different than two previously proposed mechanisms for recycling the bubbles.
Researchers photographed mouse brain cells using an electron microscope after flash-freezing the cells in the act of firing nerve signals. That showed the tiny vesicles are recycled to form new bubbles only one-tenth of a second after they dump their cargo of neurotransmitters into the gap or “synapse” between two nerve cells or neurons.
Fish Shed Light on Nerve Regeneration After Spinal Injury
Fish, unlike humans, can regenerate nerve connections and recover normal mobility following an injury to their spinal cord. Now, Univ. of Missouri researchers have discovered how the sea lamprey, an eel-like fish, regrows the neurons that comprise the long nerve “highways” that link the brain to the spinal cord. The findings may guide future efforts to promote recovery in humans who have suffered spinal cord injuries.
“There is a lot of attention to why, following a spinal cord injury, neurons regenerate in lower vertebrates, such as the sea lamprey, and why they don’t in higher vertebrates, such as humans,” says Andrew McClellan, professor of biological sciences in the College of Arts and Science and director of the MU Spinal Cord Injury Program.
Anyone who has suffered through sleepless nights due to uncontrollable itching knows that not all itching is the same. New research at Washington Univ. School of Medicine in St. Louis explains why.
Working in mice, the scientists have shown that chronic itching, which can occur in many medical conditions, from eczema and psoriasis to kidney failure and liver disease, is different from the fleeting urge to scratch a mosquito bite.
Since 2000, more than 2,000 servicemembers have suffered amputated limbs. DARPA’s breakthrough research with advanced prosthetic limbs controlled by brain interfaces is well documented, but such research is currently limited to quadriplegics; practical applications of brain interfaces for amputees are still in the future. In contrast, nerve and muscle interfaces allow amputees to control advanced prosthetics in the near term. Recent demonstrations may give Wounded Warriors hope that they can soon take advantage of these breakthroughs.
Activating an enzyme — known to play a role in the anti-aging benefits of calorie restriction — delays the loss of brain cells and preserves cognitive function in mice, according to a study published in today’s issue of The Journal of Neuroscience. The findings could one day guide researchers to discover drug alternatives that slow the progress of age-associated impairments in the brain.
Previous studies have shown that reducing calorie consumption extends the lifespan of a variety of species and decreases the brain changes that often accompany aging and neurodegenerative diseases such as Alzheimer’s. There is also evidence that caloric restriction activates an enzyme called Sirtuin 1 (SIRT1), which studies suggest offers some protection against age-associated impairments in the brain.
The field of cell therapy, which aims to form new cells in the body in order to cure disease, has taken another important step in the development towards new treatments. A new report from researchers at Lund Univ. in Sweden shows that it is possible to reprogram other cells to become nerve cells, directly in the brain.
Two years ago, researchers in Lund were the first in the world to reprogram human skin cells, known as fibroblasts, to dopamine-producing nerve cells – without taking a detour via the stem cell stage. The research group has now gone a step further and shown that it is possible to reprogram both skin cells and support cells directly to nerve cells, in place in the brain.
Researchers Get Closer to ‘That Itches,’ Not ‘That Hurts’
Johns Hopkins researchers have uncovered strong evidence that mice have a specific set of nerve cells that signal itch but not pain, a finding that may settle a decades-long debate about these sensations, and, if confirmed in humans, help in developing treatments for chronic itch, including itch caused by life-saving medications.
Fly Research Explains Humans’ Most Mysterious Physical Sense
Stroke the soft body of a newborn fruit fly larva ever-so-gently with a freshly plucked eyelash, and it will respond to the tickle by altering its movement — an observation that has helped scientists at the Univ. of California, San Francisco (UCSF) uncover the molecular basis of gentle touch, one of the most fundamental but least well understood of humans’ senses.
Our ability to sense gentle touch is known to develop early and to remain ever-present in our lives, from the first loving caresses our mothers lavish on us as newborns to the fading tingle we feel as our lives slip away. But until now, scientists have not known exactly how humans and other organisms perceive such sensations.
For the first time, scientists have improved hearing in deaf animals by using human embryonic stem cells, an encouraging step for someday treating people with certain hearing disorders. “It’s a dynamite study (and) a significant leap forward,” says one expert familiar with the work, Lawrence Lustig of the Univ. of California, San Francisco.
The experiment involved an uncommon form of deafness, one that affects fewer than 1 percent to perhaps 15 percent of hearing-impaired people. And the treatment wouldn’t necessarily apply to all cases of that disorder. Scientists hope the approach can be expanded to help with more common forms of deafness. But in any case, it will be years before human patients might benefit.
Squid’s colorful, changeable skin enables the animal—and their close relatives, cuttlefish and octopus—to display extraordinary camouflage, the speed and diversity of which is unmatched in the animal kingdom. But how squid control their skin’s iridescence, or light-reflecting property, which is responsible for the animal’s sparkly rainbow of color, has been unknown.
In a new study, Marine Biological Laboratory (MBL) researchers Paloma Gonzalez Bellido and Trevor Wardill and their colleagues report that nerves in squid skin control the animal’s spectrum of shimmering hues — from red to blue — as well as their speed of change. The work marks the first time neural control of iridescence in an invertebrate species has been demonstrated.
Nerve Stimulation in Brain May Treat Stroke, Autism
UT Dallas researchers recently demonstrated how nerve stimulation paired with specific experiences, such as movements or sounds, can reorganize the brain. This technology could lead to new treatments for stroke, tinnitus, autism and other disorders.
In a related paper, UT Dallas neuroscientists showed that they could alter the speed at which the brain works in laboratory animals by pairing stimulation of the vagus nerve with fast or slow sounds.
Scientists have developed a small molecule inhibiting drug that — in early laboratory cell tests — stopped breast cancer cells from spreading and also promoted the growth of early nerve cells called neurites. Researchers from Cincinnati Children’s Hospital Medical Center report their findings online in Chemistry & Biology. The scientists named their lead drug candidate “Rhosin” and hope future testing shows it to be promising for the treatment of various cancers or nervous system damage.
The inhibitor overcomes a number of previous scientific challenges by precisely targeting a single component of a cell signaling protein complex called Rho GTPases. This complex regulates cell movement and growth throughout the body. Miscues in Rho GTPase processes are also widely implicated in human diseases, including various cancers and neurologic disorders.
Chronic pain, by definition, is difficult to manage, but a new study by UCSF scientists shows how a cell therapy might one day be used not only to quell some common types of persistent and difficult-to-treat pain, but also to cure the conditions that give rise to them.
The researchers, working with mice, focused on treating chronic pain that arises from nerve injury — so-called neuropathic pain. In their study, published in Neuron, the scientists transplanted immature embryonic nerve cells that arise in the brain during development and used them to make up for a loss of function of specific neurons in the spinal cord that normally dampen pain signals.
Method May Restore, Repair Severely Damaged Nerves
Engineers at the Univ. of Sheffield have developed a method of assisting nerves damaged by traumatic accidents to repair naturally, which could improve the chances of restoring sensation and movement in injured limbs.
In a collaborative study with Laser Zentrum Hannover (Germany) published in the journal Biofabrication, the team describes a new method for making medical devices called nerve guidance conduits or NGCs. The method is based on laser direct writing, which enables the fabrication of complex structures from computer files via the use of CAD/CAM (computer aided design/manufacturing), and has allowed the research team to manufacture NGCs with designs that are far more advanced than previously possible.