Study Identifies Itch-specific Nerves

Scientists have been looking for itch-specific nerves for decades. New research from investigators at Johns Hopkins University and Yale University in the United States and several universities in China has identified sensory neurons in mice that are dedicated to relaying itchy sensations from the top layers of skin to the spinal cord [1]. In 1835, Johannes Peter Müller proposed the law of specific nerve energies. It stated that everything we feel and experience relies on the stimulation of particular neuronal pathways — and thus that the actual, external stimulus is irrelevant. He wrote: The same cause, such as electricity, can simultaneously affect all sensory organs, since they are all sensitive to it; and yet, every sensory nerve reacts to it differently; one nerve perceives it as light, another hears its sound, another one smells it; another tastes the electricity, and another one feels it as pain and shock. But how to divorce the stimulus from the nerve it stimulates to test this idea? As reported in a recent paper in Nature Neuroscience, an international team of researchers started by labeling a small subset of neurons in the dorsal root ganglion in mice [2]. The dorsal root ganglion is the home of neurons that mediate sensory signals, and the subset of neurons these scientists labeled is known to respond to stimuli that induce both pain and itch. They showed that these neurons exclusively innervate the epidermis — the outermost layer of the skin —...
Source: Highlight HEALTH - Category: Medical Scientists Authors: Source Type: blogs