Islet amyloid polypeptide (LAPP or amylin) is predominantly expressed by in
sulin cells, but occurs also in primary sensory neurons in the rat. Here, u
sing mice targeted for a null mutation in the IAPP gene,we establish murine
expression of IAPP in sensory neurons; its distribution in a population of
calcitonin gene-related peptide-containing neurons in the spinal cord and
dorsal root ganglion is similar to that previously described in the wt. We
also report the IAPP mutant mice display a reduced pain response in the paw
formalin test. Adjuvant-induced joint inflammation was not altered in LAPP
mutants, arguing against a peripheral inflammatory abnormality. These find
ings lead us to suggest that IAPP has a pro-nociceptive function in primary
sensory neurons. (C) 1998 Elsevier Science B.V. All rights reserved.