|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1994 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1993 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1992 : ¥1,100,000 (Direct Cost : ¥1,100,000)
The tuft cells found in the main excretory duct epithelium of the submandibular gland are also present in the hollow organs of endodermal orgin such as the respiratory systems and the alimentary systems. Their common chracteristics are the finger-like long microvilli, microtubules and microfilaments running parallel to the cell axis, and a lot of vesicles and tubules in the apical cytoplasm. However, their functions are still unknown. The following experiments were done to establish their functions
1)Vesicles and tubules contained the filamentous substance. Glycoconjugate cytochemistry were performed to prove the character of the filamentous substance. Vesicles, tubules Golgi elements and plasma membrane of the microvilli stained positive.
2)The tuft cells were studied by embedding water soluble resin LRW and postembedded staining with lectin/ colloidal-gold (CG) conjugate-Con-A,PNA,SBA,UEA-1, DBA.Con-A was observed in the vesicles and tubules in the apical cytoplasm.
3)The postnatal development of tuft cells at various stages, 0,1,7,14,21,28 and 54 days, was investigated by scanning and transmission electron microscopy. Tuft cells were already recognized at birth. Their number reached approximately 6% of the total epithelial cells. The frequency of tuft cells in the adult stage was about 7%. However, microvilli were smaller than the adult ones. In fine structure, the tuft cells at 28 days after birth reached the same level as that at birth.
The tuft cells in the main excretory duct epithelium of the rat submandibular gland seem to engage in secretory activity of glycoconjugates, which may be related to the reception because of long microvilli protruding into the lumen.