Thyroid Hormones and Motoneurons Development

It is well known that postnatal maturation of the central nervous system is critically dependent on thyroid hormone levels (Thompson & Potter, 2000) and this might influence the neuromuscular system (Barakat-Walter et al., 2000). Previous neuroanatomical and biochemical investigations demonstrated that development of skeletal muscles including the masseter is affected by both neuronal and thyroid hormonal effects (Adams et al., 1999; d’ Albis et al., 1989, 1990; Butler-Browne et al. 1984; Gambke et al., 1983; Rubinstein et al., 1988). Under normal condition the phenotypic properties of motoneurons and muscle fibers in the neuromuscular unit are matched (Copray & Kernell, 2000; Hughes & Salinas, 1999; Akihiko Ishihara, Kawano, Okiura, Morimatsu, & Ohira, 2005).