PROPRIOCEPTIVE REPRESENTATION OF THE LEVATOR VELI PALATINI MUSCLE IN THE SOLITARY NUCLEUS OF THE RAT

The levator veli palatini muscle is innervated by motoneurons of the g lossopharyngeal nerve, which are located within the ambiguus nucleus; however, little is known about the afferent fibers of this muscle. A h orseradish peroxidase study was conducted in rats following injection into the levator veli palatini muscle branch to reveal the location an d the distribution of dendrites of the afferent fibers of the muscle, Terminal labels were densely distributed in the lateral region of the solitary nucleus, which receives afferents of the glossopharyngeal ner ve, ipsilateral and contralateral to the injection site. The relations hip of the levator veli palatini muscle with respiration was suggested by the localization of labeled terminals at sites where the afferents from the respiratory organs project densely, and by the demonstrated proprioceptive role of the afferent fibers passing through the muscle spindles contained in the levator veli palatini muscle.