Pain is believed to be triggered by activation of free nerve endings without end organs in the skin. In contrast to this paradigm, Abdo et al. Discovered a previously unknown mesh-like organ that covered the skin that perceives dangerous environmental stimuli (see Doan and Monk's Perspective). This organ is made up of specialized glial cells in the epidermal-dermal boundary and is sufficient and required to initiate mechanical pain transduction.
An essential condition for the survival of an organism is the ability to detect and respond to aversive stimuli. The current belief is that harmful stimuli directly activate nociceptive sensory nerve endings in the skin. A specialized type of cutaneous glial cell was discovered with extensive processes that form a mesh-like network in the subepidermal boundary of the skin that transmits harmful thermal and mechanical sensitivity. A direct stimulating functional connection with sensory neurons is shown and evidence of a previously unknown organ that plays an essential physiological role in detecting harmful stimuli. Thus, these glial cells, closely associated with non-myelinated nociceptive nerves, are inherently mechanosensitive and transmit nociceptive information to the nerve.