CHOLINESTERASES AND CHOLINE ACETYLASE IN ISOLATED HUMAN AND RAT ODONTOBLASTS

Activity and localization of cholinesterases and activity of choline acetyltransferase was determined in isolated rat and human odontoblasts. The hydrolysis of choline esters was measured by the microdiver and radiometric assays and the activity of choline acetyltransferase by a radiometric assay. The cholinesterase activity in individual odontoblasts of man and rat was almost the same and amounted in man to 24 pmol hydrolysed substrate/odontoblast per h if 3.3 mM acetylcholine was used, and in the rat it amounted to 27 pmol hydrolysed substrate/odontoblast per h at the same concentration of acetylcholine. In odontoblast homogenates, the activity of choline acetyltransferase amounted to 6 nmol ACh/g of fresh tissue per min. Histochemical and electron-microscopic studies showed the cholinesterase localized in the subodontoblast layer and in the nucleus of the odontoblast. The presence of cholinesterase and choline acetyltransferase in odontoblasts suggests that odontoblasts possess some features of a cholinergic system. © 1979.