Journal of Dental Research, Vol 67, 1271-1274, Copyright © 1988 by International & American Associations for Dental Research Online Journals
Histochemical demonstration of carbonic anhydrase activity in the odontogenic cells of the rat incisor
T. Sugimoto, Y. Ogawa, H. Kuwahara, M. Shimazaki, T. Yagi and A. Sakai
2nd Department of Oral Anatomy, Osaka University Faculty of Dentistry, Japan.
Aldehyde-fixed, EDTA-demineralized frozen sections of the rat maxillary
incisor were histochemically stained for carbonic anhydrase activity, by
use of Hansson's method. Intense staining was observed in the odontoblasts,
all types of epithelial cells of enamel organ in the maturation zone,
cementoblasts, and the cells of the lingual dental sac. Less intense but
consistent staining was observed in all types of epithelial cells of
odontogenic origin directly facing the pulp and pulp cells adjacent to the
odontoblast cell layer in the apical part of the pulp, and was considered
due to the carbonic anhydrase-catalyzed reaction. Staining of these cells
was completely inhibited by heat pretreatment (120 degrees C, 30 min),
10(-6) mol/L acetazolamide in the incubation medium, incubation by
continuous immersion under the liquid surface, and omission of the
substrate, NaHCO3. The dentin also exhibited heavy staining which was
inhibited by the heat pre-treatment. However, this dentinal staining
resisted the inhibition by 10(-3) mol/L acetazolamide and was not inhibited
by incubation by continuous immersion or incubation without the substrate
NaHCO3. The dentinal staining was thus judged to have been due to
non-enzymatic cobalt precipitation.
