Cytochemical localization of calcium and Ca2+,Mg2(+)-adenosine triphosphatase in colchicine-altered rat incisor ameloblasts.
Colchicine is known to affect secretory, transport, and degradative functions of ameloblasts. The effects of colchicine on membrane-associated calcium and Ca2+,Mg2(+)-ATPase in secretory and maturation ameloblasts were investigated cytochemically. The pyroantimonate (PPA) method was used for localizing calcium and a modified Wachstein-Meisel medium was used to localize Ca2+,Mg2(+)-ATPase. Sections representing secretory and early maturation stages were examined by transmission electron microscopy. Morphological changes induced by colchicine included dislocated organelles and other well-established reactions to such anti-microtubule drugs. Calcium pyroantimonate (Ca-PA) deposits in most ameloblast types were markedly reduced, with the greater reduction occurring in those cells more severely altered morphologically. However, the cell membranes of both control and experimental smooth-ended maturation ameloblasts were essentially devoid of Ca-PA. The normal distribution and intensity of Ca2+,Mg2(+)-ATPase was not affected by colchicine. Because the observed reduction of membrane-associated calcium is apparently not mediated by Ca2+,Mg2(+)-ATPase in this case, other aspects of the calcium regulating system of ameloblasts are apparently targeted by colchicine.
Eisenmann
D R
DR
Department of Histology, College of Dentistry, University of Illinois, Chicago.
Salama
A H
AH
Zaki
A M
AM
Ashrafi
S H
SH
D000565:Ameloblasts / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003078:Colchicine / Q000494:pharmacology*; D006651:Histocytochemistry / Q000379:methods; D007180:Incisor / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D008854:Microscopy, Electron / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains
D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D003078:Colchicine; D002118:Calcium