Fig. 1

ASICs localize in a variety of somatosensory nerve terminals responsible for both chemo-sensing and mechano-sensing functions. In skin, ASICs are expressed in the free nerve endings of nociceptors and cutaneous nerves projecting to specialized mechanoreceptors such as Meissner corpuscles, Ruffini corpuscles, Pacinian corpuscles, hair follicles, and Merkel cells. In muscle, ASICs are expressed in the free nerve endings of nociceptors and group Ia muscle spindle nerve fibers in the intrafusal bag. In the cardiovascular system, ASICs are expressed in cardiac sensory nerves and baroreceptors. In the gut, ASICs are expressed in many subpopulations of gastrointestinal afferents. In the spinal cord, ASIC-expressing sensory afferents innervate to distinct dorsal horn laminae corresponding to their specific sensory perception