The vagal and glossopharyngeal sensory ganglia and their peripheral tissues were examined in wild type and dystonia musculorum mice to assess the effect of dystonin loss of function on chemoreceptive neurons. In the mutant mouse, the number of vagal and glossopharyngeal sensory neurons was severely decreased (70% reduction) when compared with wild type littermates. The mutation also reduced the size of the circumvallate papilla (45% reduction) and the number of taste buds (89% reduction). In addition, immunohistochemical analysis demonstrated that the dystonin mutation reduced the number of PGP 9.5-, calcitonin gene-related peptide-, P2X3 receptor- and tyrosine hydroxylase-containing neurons. Their peripheral endings also decreased in the taste bud and epithelium of circumvallate papillae. These data together suggest that the survival of vagal and glossopharyngeal sensory neurons is dependent upon dystonin.