CYTOCHEMICAL DEMONSTRATION OF NITRIC-OXIDE SYNTHASE AND 5'NUCLEOTIDASE IN HUMAN GLIOBLASTOMA

Both nitric oxide (NO), formed from L-arginine by the enzyme nitric ox ide synthase (NOS), and adenosine, which is produced by 5'nucleotidase (5'N) acting on adenosine 5'monophosphate (5'AMP) are implicated in s everal neurophysiological processes. In addition 5'N is a linker prote in involved in cell motility. Alterations of both enzyme activities se em to be responsible for some pathological states of the central nervo us system (CNS). In the present report, we have studied the cytochemic al demonstration of NOS and 5'N activities in human glioblastoma cells . Enzyme activity of both was observed in tumor cells; moreover, the c oincidence of enzyme histochemistry and immunohistochemistry for NOS w as noted in most cases. The findings were interpreted on the basis of the cytotoxic effects due to NO production by tumor cells, and on the non-catalytic role of membrane 5'N which acting as an adhesive molecul e can favour tumor invasiveness.