Electron microscopy and immunohjstochemistry on neurotrophic effects of chorda timpani nerve

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 10671728
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Morphological basic dentistry
• Research Institution: Fukuoka Dental College
• Principal Investigator: NAGATO Toshikazu Fukuoka Dental College, Department of Morphological Biology, Professor, 歯学部, 教授 (80084284)
• Co-Investigator(Kenkyū-buntansha): YAHIRO Junko Fukuoka Dental College, Department of Morphological Biology, Professor, 歯学部, 助手 (60105682)
• Project Period (FY): 1998 – 2000
• Keywords: neurotrophic fanction / chorda-timpaninerve / parasvmpathetic nerve / funqiform papilla / acinar cell / myoepithelial cell / jon etching / three dimensional reconstruction

Research Abstract

1. To elucidate the trophic function fo chorda tympani nerve, unilateral denervation wasperformed. When mature fungi form papillae were neurectomized, the papillae were atrophic, then progressed to forms resembings filiform papillae. When immature fungi form papillae were neurectomized, it eventually changed to a papilla identical to normal filiform papillae. When mature fungi form papillae were nerve-crushed, the papillae degenerated, then began to redifferentiate to normal fungi form papillae. However, if the immature papillae were denervated by nerve crush, the papillae changed to quasi-filiform papillae, and some of them could not redifferentiate to normal fungi form papillae. These findings suggest that fungi form papillae may be transformed filiform papillae induced and maintained by a neurotrophic factor of chorda tympani nerve. When sublingual gland was denervated at perenatal period, unusual acini and myoepithelial cells were observed. Based on this finding, it is supposed tha tthe chorda tympani nerve participates in the differentioation of acinar and myoepithelial cells.
2. Histoarchitecture and development of rat Weber's glands were examined. Adult Weber's glands were composed of numerous terminal portions and duct-like structures. The terminal portions were tubuloacinar in shape and were mixed, consisting of mucous acini that often capped by serous demilunes. Weber's glands in the newborn rat were composed of four cell types ; serous, mucous, intermediate, and undifferentiated cells. Undifferentiated cells were abundant at birth and disappear by 3 weeks after birth. Srous cells were numerous at 1 postnatal week, then decrease, with a few remaining as demilunes. Mucous cells were rare until 1 week after birth, then increased and became the predominant cell type after 3 postnatal weeks. Intermediate cells were most numerous until 2 weeks after birth, then decreased and disappear by 5 weeks after birth. These findingssuggest that rat Weber's glands are most useful glands to analyze the trophic function of glossopharyngeal nerve.