Epithelial Na+ channels and stomatin are expressed in rat trigeminal mechanosensory neurons

Caenorhabditis elegans MEC-4 and MEC-10 are subunits of the degenerin/epith elial Na+ channel (DEG/ENaC) ion channel superfamily thought to be associat ed with MEC-2 (a stomatin-like protein) in a mechanotransducing molecular c omplex in specialized touch sensory neurons. A key question is whether anal ogous molecular complexes in higher organisms transduce mechanical signals. To address this question, we selected mechanoreceptors of the rat vibrissa l follicle-sinus complex in the mystacial pad and the trigeminal ganglia fo r an immunocytochemical and molecular biological study. RT-PCR of poly(A+) mRNA of rat trigeminal ganglia indicated that alpha-, beta-, and gamma-ENaC and stomatin mRNA are expressed in rat trigeminal ganglia, Using immunocyt ochemistry, we found that alpha-, beta-, and gamma-ENaC subunits and stomat in are localized in the perikarya of the trigeminal neurons and in a minor fraction of their termination site in the vibrissal follicle-sinus complex, where longitudinal lanceolate endings are immunopositive. We conclude that alpha-, beta-, and gamma-ENaC subunits as well as the candidate interactin g protein stomatin are coexpressed in a mammalian mechanoreceptor, a locati on consistent with a possible role in mechanotransduction.