Antibodies specific to Gaq, PLCβ, Gai 1-2, and PKA were immunohistochemically (IHC) localized in the pre-ameloblasts up to initial dentin matrix deposition and continued in the distal ends of the pre-secretory ameloblasts to the beginning of enamel matrix secretion. It was hypothesized that the endothelin B receptor (ETBR) and/or the extracellular Ca2+-sensing receptor (CaR) would localize in the same locations as their known downstream signal transduction pathway (STP) effectors during events related to early amelogenesis. Localization was similar for the 4 signal transduction pathway elements and the CaR. The ETBR was not localized in any of the cells of the enamel organ. These findings indicate that the CaR and its related STPs are expressed in the pre-ameloblasts and pre-secretory ameloblasts in positions where they may be able to detect increases in extracellular Ca2+ concentrations observed in the pre-dentin matrix in a previous study. These observations are consistent with the hypothesis that increased levels of free Ca2+ in the pre-dentin matrix serve as a primary signal for modification of gene expression important to amelogenesis.
Abdel-Latif AA (1986). Calcium-mobilizing receptors, polyphosphoinositides, and the generation of second messangers. Pharmacol Rev38:227-272.
2.
Battistini B., Chailler P., D'Orleans-Juste P., Brie'r N., Sirois P. (1993). Growth regulatory properties of endothelins. Peptides14:385-399.
3.
Bawden JW (1989). Calcium transport during mineralization. Anat Rec224:226-233.
4.
Bawden JW, Rozell B., Wurtz T., Fouda N., Hammarstrom L. (1994). Distribution of protein kinase C alpha and accumulation of extracellular Ca2+ during early dentin and enamel formation. J Dent Res73:1429-1436.
5.
Bawden JW, Moran RA, Deaton TG, Saour CM (1996). Immunohistochemical localization of signal transduction pathways during amelogenesis: an initial exploration. Adv Dent Res10:105-110.
Brown EM (1991). Extracellular Ca2+ sensing, regulation of parathyroid cell function, and role of Ca2+ and other ions as extracellular (first) messengers . Physiol Rev71:371-411.
8.
Brown EM (1999). Physiology and pathophysiology of the extracellular calcium-sensing receptor. Am J Med106:238-253.
9.
Brown EM, Hebert SC (1995). A cloned Ca2+-sensing receptor: a mediator of direct effects of extracellular Ca2+ on renal function? J Am Soc Nephrol6:1530-1540.
10.
Brown EM, Gamba G., Riccardi D., Lombardi M., Butters R., Kifor O., et al. (1993). Cloning and characterization of an extracellular Ca2+sensing receptor from bovine parathyroid. Nature366:575-580.
11.
Brown EM, Vassilev PM, Hebert SC (1995). Calcium ions as extracellular messengers. Cell83:679-682.
12.
Brown EM, Harris WH, Vassilev PM, Hebert SC (1996). The biology of the extracellular Ca2+-sensing receptor. In: Principles of bone biology. Raiz LG, Rodan G , editors. San Diego: Academic Press, pp. 243-262.
13.
Bustelo XR, Rubin SD, Suen KL, Carrasco D., Barbacid M. (1993). Developmental expression of the vav protooncogene . Cell Growth Differ4:297-308.
14.
Butters RR Jr, Chattopadhyay N., Nielsen P., Smith CP, Mithal A., Kifor O., et al. (1997). Cloning and characterization of a calcium-sensing receptor from the hypercalcemic New Zealand white rabbit reveals unaltered responsiveness to extracellular calcium. J Bone Miner Res12:568-579.
15.
Casasco A., Calligaro A., Casasco M., Springall DR, Tenti P., Marchetti C., et al. (1991). Immunohistochemical localization of endothelin-like immunoreactivity in human tooth germ and mature dental pulp. Anat Embryol183:515-520.
16.
Filvaroff E., Calautti E., Reiss M., Dotto GP (1994). Functional evidence for an extracellular calcium receptor mechanism triggering tyrosine kinase activation associated with mouse keratinocyte differentiation. J Biol Chem269:21735-21740.
17.
Hammarstrom L. (1967). Different localization of tetracycline and simultaneously injected radiocalcium in developing enamel. Calcif Tissue Res1:229-242.
18.
Hebert SC, Brown EM (1995). The extracellular calcium receptor. Curr Opin Cell Biol7:484-492.
19.
Huggins JP, Pelton JT, Miller RC (1993). The structure and specificity of endothelin receptors: their importance in physiology and medicine. Pharmacol Ther59:55-123.
20.
Jaken S., Yuspa SH (1988). Early signals for keratinocyte differentiation: role of Ca2+-mediated inositol lipid metabolism in normal and neoplastic epidermal cells. Carcinogenesis9:1033-1038.
21.
Josephsen K., Fejerskov 0, Baelum V., Weile V. (1990). The effect of a single dose of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) on presecretory ameloblast differentiation in rat incisors. J Biol Buccale18:321-377.
22.
Jouneaux C., Goldsmith P., Hanoune J., Lotersztajn S. (1993). Endothelin inhibits the calcium pump and stimulates phosphoinositide phospholipase C in liver plasma membranes via two different G-proteins, Gs and Gq. J Cardiovasc Pharmacol22(Suppl 8):S158-S160.
23.
Jouneaux C., Mallat A., Serradeil-Le Gal C., Goldsmith P., Hanoune J., Lotersztajn S. (1994). Coupling of endothelin B receptors to the calcium pump and phospholipase C via Gs and Gq in rat liver. J Biol Chem269:1845-1851.
24.
Karcher-Djuricic V., Staubli A., Meyer JM, Ruch JV ( 1985). Acellular dental matrices promote functional differentiation of ameloblasts. Differentiation29:169-175.
25.
Maki A., Berezesky IK, Fargnoli J., Holbrook NJ, Trump BF (1992). Role of Ca2+ in induction of c-fos, c-jun and c-myc mRNA in rat PTE after oxidative stress. FASEB J6:919-924.
26.
Otsuji W., Tanase S., Yoshida S., Bawden JW (1999). The immunohistochemical localization of the interferon-gamma and granulocyte colony-stimulating factor receptors during early amelogenesis in rat molars. Arch Oral Biol44:173-181.
27.
Riccardi D., Lee WS, Lee K., Segre GV, Brown EM, Hebert SC (1996). Localization of the extracellular Ca2+-sensing receptor and PTH/PTHrP receptor in the rat kidney. Am J Physiol271:F951-F956.
28.
Ruch JV ( 1987). Epithelial-mesenchymal interactions in formation of mineralized tissues. In: The chemistry and biology of mineralized tissues . Butler WT, editor. Birmingham, AL: Ebsco Media, p. 58.
29.
Sandros J., Heikinheimo K., Happonen RP, Stenmen G. (1991). Expression of p21 RAS in odontogenic tumors. APMIS99:15-20.
30.
Stryjek-Kaminska D., Piiper A., Zeuzen S. (1996). Epidermal growth factor regulates adenylate cyclase activity via Gs and Gil-2 proteins in pancreatic acinar membranes. Biochem J316:87-91.
31.
Tanase S., Bawden JW (1996a). The immunohistochemical localization of signal-transduction pathway components Jak1, Jak2, Jak3, Tyk2 and STAT-1 during early enamel and dentine formation in rat molars. Arch Oral Biol41:925-940.
32.
Tanase S., Bawden JW (1996b). The immunohistochemical localization of stat-2, -3, -4 and -5 during early enamel and dentine formation in rat molars. Arch Oral Biol41:1149-1160.
33.
Ten Cate AR (1989). Oral Hhstology: development, structure, and function . Baltimore: The C.V. Mosby Co. , pp. 197-212.
34.
Teti A., Colucci S., Grano M., Argentino L., Zambonin-Zallone A. (1992). Protein kinase C affects micro filaments, bone resorption, and [Ca2+] sensing in cultured osteoclasts. Am J Physiol263:C130-139.
35.
Thesleff I., Nieminen P. (1996). Tooth morphogenesis and cell differentiation. Curr Opin Cell Biol8:844-850.
36.
Ullberg S. (1954). Studies on the distribution and rate of 33S labeled benzyl-penicillin in the body. Acta Radiol (Suppl):118.
37.
Ward DT, Brown EM, Harris HW (1998). Disulfide bonds in the extracellular calcium-polyvalent cation-sensing receptor correlate with dimer formation and its response to divalent cations in vitro. J Biol Chem273:14476-14483.
38.
Woltgens JH, Lyaruu DM, Bervoets TJ, Bronkers AL (1987). Effects of calcium and phosphate on secretion of enamel matrix and its subsequent mineralization in vitro. Adv Dent Res1:196-201.
