The purpose of this study is to analyse the effect of recurrent laryngeal nerve denervation on postnatal developement of intrinsic laryngeal muscle fibers. The composition of muscle fiber types in the medial component of thyroarytenoid muscle (m-TA), the lateral component of thyroarytenoid muscle (1-TA) and the posterior cricoarytenoid muscle (PCA) has been compared between normal and denervated rats using myosin ATPase stain method.
With denervated rats, Type 1 fibers disappear rapidly after denervation. Type 2A fibers do not appear through the observed period. On the other hand, the developmental changes of Type 2B fibers are almost similar to those of normal rats. The denervation prevents the differentiation of Type 1 and 2A fibers, but almost does not change the differentiation of Type 2B fibers.
These results suggest that the recurrent laryngeal nerve has an important role at its specified course of postnatal differentiation of intrinsic laryngeal muscle fibers.