The effects of colchicine on the ultrastructure of odontogenic cells in the common skate, Raja erinacae

• Published in: American Journal of Anatomy
• Main Authors: Prostak, Kenneth, Seifert, Philip, Skobe, Ziedonis
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1990
• Subjects: Common skate
• Online Access: http://dx.doi.org/10.1002/aja.1001890110; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Faja.1001890110; https://onlinelibrary.wiley.com/doi/pdf/10.1002/aja.1001890110

Abstract Ultrastructural alterations in duced by colchicine were investigated to determine the secretory activities of odontogenic cells during formation of tooth enameloid matrix in skates. Treated skate inner dental epithelial (IDE) cells did not display dilated cisternae of the granular endoplasmic reticulum (GER) nor accumulate Golgi‐associated secretory granules at any dose level or time interval examined. This response was markedly different from that observed in teleost IDE cells synthesizing the enameloid collagen matrix. Treated skate IDE cells did show increased accumulations of glycogencontaining vesicles and intercellular glycogen associated with amorphous material, compared to controls. Additionally, the aberrant occurrence of large intracellular glycogen pools and amorphous material suggested that carbohydrate processing was a major function of skate IDE cells. Treated odontoblasts associated with enameloid matrix formation sometimes showed dilated GER cisternae, but procollagen secretory granules were not obsered. Instead, electron dense material was present within the Golgi cisternae, tubular granules, and large granules. Some elecron‐dense material appeared to be shunted to a resorptive pathway via multivesicular bodies in treated odontoblasts. The continuity of tubular granules with the enameloid matrix suggested that they contained precursors of the enameloid matrix, and possibly the periodic, 17.5‐nm crossstriated, “giant” fibers. Treated odontoblasts associated with predentin collagen matrix deposition showed dilated GER cisternae and accumulations of procollagen secretory granules, features consistent with the function of active collagen synthesis and secretion. The findings indicate that (1) skate IDE cells do not synthesize enameloid collagen as found in bony fish tooth development; (2) skate IDE cells do process glycogen for secretion into the enameloid matrix; (3) collagen, although present, is not a major constituent of skate enameloid matrix; (4) enameloid “giant” fibers are unique to ...