Morphological Development and Expression of Neurotrophin Receptors in the Laryngeal Sensory Corpuscles

Abstract

Morphological development of sensory structures in the laryngeal mucosa of postnatal rats was observed by use of immunohistochemistry for protein gene-product 9.5 (PGP9.5). Moreover, expression changes of high affinity neurotrophin receptors, TrkA, TrkB and TrkC, and low affinity neurotrophin receptor p75 NTR were examined to elucidate the relationship to morphogenesis. Intraepithelial nerve endings and parent axons of the laminar endings with immunoreactivity for PGP9.5 have already appeared in the rat on embryonic day 18 (E18) as well as solitary chemoreceptor cells in the glottic cleft. According to neurotrophin receptors, TrkA immunoreactivity were observed on and after postnatal week 3 (3W) in the nervous sensory structures, that is, free nerve endings, laminar endings and sub-and intragemmal plexuses of the taste buds. In the laminar endings, TrkC immunoreactivity was also observed on and after 3W. According to the laryngeal sensory cells, the solitary chemoreceptor cells were immunoreactive to TrkA, TrkB, and TrkC on and after postnatal day 3 (P3). In the taste buds in arytenoid region, taste cells were immunoreactive for TrkA, TrkB, and TrkC on and after 3W, P14, and 3W, respectively. Immunoreactivity for p75 NTR was observed on the surface of taste cells on and after P9. The results of the present study suggest that sensory structures in the laryngeal mucosa were developed on perinatal days to involve respiratory reflex, and that neurotrophin receptors may take part in the regulation and maintenance of sensory structures. Anat Rec, 294:694-705, 2011. V V C 2011 Wiley-Liss, Inc.

Morphology of GNAT3‐immunoreactive chemosensory cells in the rat larynx

“…Our previous study revealed that TrkB was expressed in laryngeal chemosensory cell clusters, even in the postnatal rats (Yamamoto et al. ). The neurotrophic effects of BDNF may be one of the important factors for development of the chemosensory cell clusters in the larynx.…”

“…In CreERT2 Bdnf lox/À mice without BDNF in taste cells, the number of cells per taste bud was reduced and the cells less innervated (Meng et al 2015). Our previous study revealed that TrkB was expressed in laryngeal chemosensory cell clusters, even in the postnatal rats (Yamamoto et al 2011). The neurotrophic effects of BDNF may be one of the important factors for development of the chemosensory cell clusters in the larynx.…”

Enhancement of aging rat laryngeal muscles with endogenous growth factor treatment

“…It has been proposed that TrkB may take part in the maintenance and protection of sensory structures in the laryngeal mucosa (Yamamoto et al. ). The appearance of higher levels of endogenous TrkB and its increase with treatment suggests the possible enhancement of NMJ transmission with systemic treatment.…”

“…These experiments were conducted in soleus muscle, which is composed of mostly slow muscle fibers, whereas the ILMs are mostly fast muscle fibers (Conner et al 2002). It has been proposed that TrkB may take part in the maintenance and protection of sensory structures in the laryngeal mucosa (Yamamoto et al 2011). The appearance of higher levels of endogenous TrkB and its increase with treatment suggests the possible enhancement of NMJ transmission with systemic treatment.…”