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Abstract

We have studied the postnatal development of the intrinsic nervous system in the circumvallate papilla-vonEbner gland complex using NADPH-diaphorase cytochemistry, immunocytochemistry (for nitric oxide synthase-1 and alpha-internexin) and electron microscopy. In rats sacrificed in their first day post partum (1 p.p.), only isolated NADPH-diaphorase positive neurons were visible in the organ. At 2 p.p., a small group of neurons was visible at the base of the papillae and positive neurons formed short chains close to the developing glandular tubules. In the following days, the NADPH-diapharase positive cells increased in number and nerve fibres were associated to small ganglia located at the base of the papilla or in the gland. After the first week of extrauterine life, the intrinsic nervous system was similar to the intrinsic system of adult animals. An immunocytochemical positivity for nitric oxide synthase-1 appeared at 4 p.p. in neurons located in the gland and at 7 p.p. in cells located at the base of the papilla. Immunocytochemical staining for alpha-internexin showed that at 1 p.p. developing nerve fibres were present in the connective tissue of the tongue's muscle layer. At 2-3 p.p., developing nerve fibres were also present at the bases and in the core of the papilla. In the following days, the positivity for alpha-internexin was reduced and one week after birth was virtually absent. Ultrastructural examination revealed that since 1 p.p. isolated neurons can be found at the base of the papilla. In conclusion, the intrinsic nervous system originates from neurons present in the organ at the birth which, in the first days, undergo a biochemical and morphological maturation while the nerve fibres rapidly grow. These findings support the hypothesis that the intrinsic nervous system of the circumvallate papilla has a role in the maturation of the vonEbner gland.

Lgr5+ductal cells of von Ebner’s glands are stem cells for turnover of posterior tongue taste buds

“…In addition to their structural differences, anterior and posterior papillae have distinct embryological origins. While fungiform papillae are presumed to arise from ectoderm, both circumvallate and foliate papillae are endodermal derivatives (Rothova et al, 2012) that develop in tandem with their associated salivary glands (Jitpukdeebodintra et al, 2002; Lee et al, 2006; Sbarbati et al, 2000,2001; Sohn et al, 2011).…”

“…The copyright holder for this preprint (which this version posted April 20, 2024. ; https://doi.org/10.1101/2024.04.18.589316 doi: bioRxiv preprint have distinct embryological origins. While fungiform papillae are presumed to arise from ectoderm, both circumvallate and foliate papillae are endodermal derivatives (Rothova et al, 2012) that develop in tandem with their associated salivary glands (Jitpukdeebodintra et al, 2002;Lee et al, 2006;Sbarbati et al, 2000Sbarbati et al, ,2001Sohn et al, 2011). The peripheral taste system of vertebrates is unusual among sensory pathways in that its cellular components are continually turned over in adult animals (Beidler and Smallman, 1965;Conger and Wells, 1969;Farbman, 1980).…”