Journal of Dental Research, Vol 66, 1702-1707, Copyright © 1987 by International & American Associations for Dental Research Online Journals

ARTICLES

The influence of vanadate on calcium uptake in maturing enamel of the rat incisor

Y. Takano, S. Matsuo, S. Wakisaka, H. Ichikawa, S. Nishikawa and M. Akai
1st Department of Oral Anatomy, Osaka University, Faculty of Dentistry, Japan.

The influence of vanadate, a potent inhibitor of Ca2+-ATPase and Na+-K+-ATPase, on 45Ca uptake in maturing enamel of the rat incisor was investigated by a vascular perfusion method combined with 45Ca autoradiography. The morphological integrity of the maturation-stage enamel organ was well-retained during vascular perfusion under all the experimental conditions. Distinct patterns of 45Ca labeling, comparable with those found in previous in vivo 45Ca autoradiographic studies, appeared in the maturing enamel after vascular perfusion with a standard perfusate. One mmol/L vanadate added to the standard perfusate caused a drastic decrease in 45Ca uptake in the maturing enamel, corresponding to the ruffle-ended ameloblasts, leaving narrow peaks of moderate intensity corresponding to the bands of the overlying smooth-ended ameloblasts. The in vitro labeling of exposed enamel surfaces with 45Ca revealed blackening of autoradiographic emulsion in wide bands separated by unlabeled or slightly labeled narrow ones resembling the distribution of smooth-ended ameloblasts in both control and vanadate-treated incisors. Our observations indicate that the ruffle-ended ameloblasts of the rat incisor serve as an efficient diffusion barrier to calcium ions and regulate transcellular calcium transport to the maturing enamel, at least in part, by a vanadate-sensitive mechanism.

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