Demonstration of sensory innervation of rat tongue with anterogradely transported horseradish peroxidase.

Wheat germ agglutinin-horseradish peroxidase injected into the petrosal ganglion in rats was transported to the posterior tongue in the glossopharyngeal nerve. Labelled fibers innervated the ipsilateral foliate papilla only, but both ipsi-and contralateral sides of the single circumvallate papilla. Somatosensory fibers in the posterior tongue also were labelled. Label crossed transcellularly from the afferent fibers into taste bud cells. Use of this method provides more detailed knowledge of sensory innervation of the tongue than previously available.