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Abstract: The mechano and chemosensory organs of adult teleosts undergoes a continuous cell renewal and turnover which is regulated in part by growth factors. Here, we investigated the occurrence and the cell localization of epidermal growth factor (EGF) in the lateral line system and taste bud of adult zebrafish, using Western blot and immunohistochemistry associated to a polyclonal antibody against mammalian EGF. Furthermore, the distribution of S100 protein was studied in parallel to label hair sensory cells in the lateral line system. Western blot revealed one unique protein band with an estimated molecular weight of about 13kDa, equivalent to the EGF of mammals. Specific immunoreactivity for EGF was observed in the epithelial basal and/or supporting cells of the neuromasts of the lateral line system and taste buds. Conversely, the sensory cells in both sensory structures were devoid of immunostaining. Present results demonstrate the occurrence of EGF in mechano and sensory system of adult zebrafish, suggesting a role for this molecule in the cell renewal and turnover of these structures. [Copyright &y& Elsevier]

The human craniofacial muscles innervated by the facial nerve typically lack muscle spindles. However these muscles have proprioception that participates in the coordination of facial movements. A functional substitution of facial proprioceptors by cutaneous mechanoreceptors has been proposed but at present this alternative has not been demonstrated. Here we have investigated whether other kinds of sensory structures are present in two human facial muscles (zygomatic major and buccal). Human checks were removed from Spanish cadavers, and processed for immunohistochemical detection of nerve fibers (neurofilament proteins and S100 protein) and two putative mechanoproteins (acid-sensing ion channel 2 and transient receptor potential vanilloid 4) associated with mechanosensing. Nerves of different calibers were found in the connective septa and within the muscle itself. In all the muscles analysed, capsular corpuscle-like structures resembling elongated or round Ruffini-like corpuscles were observed. Moreover the axon profiles within these structures displayed immunoreactivity for both putative mechanoproteins. The present results demonstrate the presence of sensory structures in facial muscles that can substitute for typical muscle spindles as the source of facial proprioception., (Copyright © 2017 Elsevier B.V. All rights reserved.)