title: Islet amyloid polypeptide (amylin) is expressed in sensory neurons.
abstract: Islet amyloid polypeptide (IAPP) or amylin is a hormone candidate predominantly expressed in insulin cells. A role for IAPP in the regulation of glucose homeostasis and the development of non-insulin-dependent diabetes mellitus has been proposed. IAPP is structurally related to the sensory neuropeptide calcitonin gene-related peptide. In the present study, using in situ hybridization, immunocytochemistry, and immunochemistry, the expression of IAPP in sensory neurons in the rat was investigated. IAPP was expressed in a population of small- to medium-sized nerve cell bodies in dorsal root ganglia from all levels and in the jugular-nodose and trigeminal ganglion; IAPP-expressing nerve cell bodies constituted a subpopulation of those expressing calcitonin gene-related peptide. In addition, IAPP-like immunoreactivity occurred in nerve cell bodies storing substance P and pituitary adenylate cyclase-activating polypeptide. IAPP-immunoreactive nerve fibers were encountered in the dorsal horns of the spinal cord, and to a lesser extent in peripheral tissues receiving sensory innervation; IAPP-immunoreactive fibers constituted a subpopulation of those containing calcitonin gene-related peptide and/or substance P. The immunochemical determinations demonstrated a low level of IAPP-like immunoreactivity in the dorsal root ganglia and spinal cord, which chromatographically coeluted with authentic rat IAPP. We conclude that IAPP is expressed in sensory neurons, thus being a novel sensory neuropeptide candidate for which a physiological role remains to be identified.
mesh_terms: D000682:Amyloid / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005260:Female; D017950:Ganglia, Sensory / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D058228:Islet Amyloid Polypeptide; D009475:Neurons, Afferent / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism
chemical_list: D000682:Amyloid; D058228:Islet Amyloid Polypeptide