A histochemical study of the activity of nonspecific cholinesterase in C6 glioma cells in culture.

Abstract

The activity of nonspecific cholinesterase (nChE) was revealed histochemically in a small number of C6 glioma cells under conditions of spontaneous growth in culture. The nChE-positive cells (nChE+) first appeared in 4-day-old cultures. They occurred solitarily or in small groups with a cluster- or chain-like arrangement. The incidence of nChE+ cells increased with in vitro age and/or higher population densities of cultures but it never exceeded 3% of the whole population. These results indicate the necessity of histochemical as well as biochemical data on nChE activity in glioma cells both in situ and in culture for the discovery of the heterogeneous distribution of this enzyme. db-cAMP induced a decrease in the proportion of nChE+ cells to total number of cells. These changes suggest that the original C6 glioma cell seed stock contains a small subclone of less differentiated cells exhibiting nChE activity. The greater number of nChE+ cells in older cultures is probably due to recovery and multiplication of initially scarce subclone cells. C6 glioma cells in culture form a suitable model for investigation of changes in nChE activity of glial cells provided that a histochemical method of detection is applied.