• Ryo Ikeda, Myeounghoon Cha, Jennifer Ling, Zhanfeng Jia, Dennis Coyle, and Jianguo G Gu.
• Pain Research Center, Department of Anesthesiology, The University of Cincinnati College of Medicine, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH 45267-0531, USA; Department of Orthopaedic Surgery, Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan.
• Cell. 2014 Apr 24; 157 (3): 664-75.

AbstractSensory systems for detecting tactile stimuli have evolved from touch-sensing nerves in invertebrates to complicated tactile end organs in mammals. Merkel discs are tactile end organs consisting of Merkel cells and Aβ-afferent nerve endings and are localized in fingertips, whisker hair follicles, and other touch-sensitive spots. Merkel discs transduce touch into slowly adapting impulses to enable tactile discrimination, but their transduction and encoding mechanisms remain unknown. Using rat whisker hair follicles, we show that Merkel cells rather than Aβ-afferent nerve endings are primary sites of tactile transduction and identify the Piezo2 ion channel as the Merkel cell mechanical transducer. Piezo2 transduces tactile stimuli into Ca(2+)-action potentials in Merkel cells, which drive Aβ-afferent nerve endings to fire slowly adapting impulses. We further demonstrate that Piezo2 and Ca(2+)-action potentials in Merkel cells are required for behavioral tactile responses. Our findings provide insights into how tactile end-organs function and have clinical implications for tactile dysfunctions.Copyright © 2014 Elsevier Inc. All rights reserved.

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