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    Vampire Bat: What Steers Vampires to Blood WWW.GOODNEWS.WS

    482 visualizzazioni Scientists have known for years that when vampire bats tear through an animal's skin with their razor-sharp teeth, their noses guide them to the best spots -- where a precise bite will strike a vein and spill forth nourishing blood. But nobody knew exactly how bats knew where to bite.By investigating wild vampire bats in South America, researchers at the University of California, San Francisco and Instituto Venezolano de Investigaciones Científicas in Caracas, Venezuela have discovered their secret: a sensitive, heat-detecting molecule covering nerve endings on their noses called TRPV1. A number of pharmaceutical and biotech companies are working on developing new pain medications that target molecules like TRPV1. "Vampire bats feed on blood, and it's useful for them to have an infrared detector to be able to find the circulation," said David Julius, PhD, the Morris Herzstein Chair in Molecular Biology & Medicine at UCSF, who led the research. Similar TRPV1 molecules can be found on pain sensing nerve fibers in human tongue, skin or eyes. They allow people to detect the chemical capsaicin in chili peppers and experience the burning tinge of spicy food. Described this week in the journal Nature, the discovery highlights how small changes to genes in the genome of a species can contribute to major evolutionary adaptations over time -- in this case, allowing the vampire bat to detect infrared heat from their prey, helping them efficiently find and feed on blood.The work also adds a piece to a larger puzzle related to human health and drug design because these same molecules are involved in pain sensation, such as that associated with touching a hot object, or hypersensitivity to heat after injury and inflammation -- as occurs with sunburn. "There is a double-edged sword with pain," Julius said. "Pain is necessary as a warning system to let us know when we are in danger of injury but, at the same time, pain can outlive its usefulness as a warning system when it fails to resolve and becomes chronic and debilitating." Sensory Nerves -- How the Brain Experiences the World. The human brain does not connect directly with the world but instead floats secluded in a protective bubble of cerebrospinal fluid within the skull. All the information the brain receives about Earthly sights, smells, textures, and tastes comes through long nerve fibers that make up the body's sensory system, which connect the brain with our eyes, noses, fingers and tongues. At the ends of these nerve fibers, cues that give life to our perception of the world are collected. Tiny molecular channels covering these nerve endings can alternatively open or close if they perceive the proper stimulus from a chemical, heat, cold or the pressure of touch. When they do, and when the right balance of openings and closings occurs all over a nerve ending, that nerve will fire, sending a signal to the brain that says "hot" or "cold" or "hard" or "bitter" or "pretty"? (something for taste and sight) depending on the type of stimulus. This basic physiology informs our awareness and also warns our brains about noxious dangers of the world. Painful stimuli signal danger to the brain and cause us to wince, squint, gasp or otherwise pull away to protect ourselves... Read the full story » Vampire Bat: What Steers Vampires to Blood WWW.GOODNEWS.WS