[The effect of opioid peptides on a decreased proliferation and on an increased maturation rate of glioma C-6 cells manifested by enhanced marker enzyme activity].

A study was made of the effect of opioid peptides, (Leu)-enkephalin and its synthetic analog dalargin, on the maturation speed (differentiation) and proliferation activity of glioma C-6 cells. This effect on phenotypes of glioma C-6 cells was determined using some biochemical parameters: changes in the activity of glutamine synthetase (astrocytic marker) and cyclic nucleotide phosphorohydrolase (oligodendrocytic marker) in the culture of glioma C-6 cells in the early and late passages. The biochemical analysis was made at the Laboratory in Denver, USA, and we thank Prof. A. Vernadakis for the possibility to carry out a part of this work that helped us to find the growth activity of opioid peptides on the C-6 cells. Proliferation was examined in cultivation conditions approximately conforming the conditions of cultivation for the primary glial cell cultures. The control proliferation level was high in this case. It is demonstrated that opioid peptides accelerate (or strengthen) the expression of phenotypic signs in C-6 glioma cells in early and late passages changing specific activity of the marker enzymes, i.e. operating as a growth factor. Opioid peptides show glial growth factor characteristics on the glioma C-6 glial cell model as well, for glioma C-6 is known to be a perfect model to analyse the action of different substances on the glia.