The motor innervation of the rat masseter muscle: A choleragenoid tracer study

M. W. Dieterle, P. J. Acton, T. Duong, T. C. Marting, K. E. Byrd

Research output: Contribution to journalArticle


The localization and morphology of trigeminal motoneurons (Vmo) that innervate rat masticatory muscles have been respectively determined by previous retrograde tracer and Golgi staining studies. In this study, we tested the use of a choleragenoid tracer, cholera toxin B (CTB) subunit, to simultaneously reveal the morphology and localization of Vmo innervating the masseter. The masseter muscles of five male Sprague-Dawley rats were unilaterally injected with CTB and the rats were perfused after a 3-day survival. Coronal and sagittal sections (40μm-thick) were obtained using a cryostat and processed for immunohistochemistry using an anti-choieragenoid primary antibody (List, Campbell, CA). The CTB labeled the perikarya and dendritic arbors of Vmo innervating the masseter. The majority of retrograde labeled Vmo were large cells with as many as 4 primary dendrites. Occasional smaller, spherical neurons were also labeled. All the retrograde labeled Vmo were located in the central and lateral portions of the nucleus. Their dendrites radiated in all directions if the perikaryon was centrally located in the nucleus, hut they radiated toward the center of the nucleus if the perikaryon was situated on the periphery. Dendritic spines were not observed. The present results are in concordance with previous, separate retrograde tracer and Golgi studies. CTB is thus an efficient retrograde tracer for simultaneous demonstration of the neu-ronal morphology and connectivity.

Original languageEnglish (US)
Pages (from-to)A200
JournalFASEB Journal
Issue number3
StatePublished - Dec 1 1997

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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