Cellular localization of cyclic AMP in periodontal tissues during experimental tooth movement in cats

Using an immune-histochemical method, cyclic AMP was localized in cells of periodontal tissues in orthodontically-treated cats. Sixteen cats were treated for periods ranging from 1 hour to 4 weeks. Fresh, frozen, undecalcified 6 mu sections of the tissues were incubated with rabbit anti-cyclic AMP antibodies, followed by sequential incubations with sheep anti-rabbit IgG, rabbit anti-peroxidase IgG and horseradish peroxidase. In the final step, the peroxidase was demonstrated by the diaminobenzidine (DAB) method. It was found that the number of intensely stained cells increased within a short time in areas in which bone resorption or apposition occurred later. However, differences in the pattern of cellular activation were found to exist between areas of compression and tension. The alveolar osteocytes appeared to be affected to only a slight degree by the applications of mechanical forces. These results indicate: (a) that our immune-histochemical method was useful in following the cellular distribution of cyclic AMP during bone remodeling; and (b) that mechanical forces may affect only a small part of the bone cell population and therefore cannot be regarded as an efficient means to bring about extensive bone remodeling.