The biochemical analysis of neurotransmitters in central neurocytomas

Central neurocytomas are rare benign intraventricular tumours composed of s mall round synaptophysin-positive cells, suggesting a neuronal origin of th ese tumour cells. Although past electron microscopic studies demonstrated s ynaptic vesicles in the synapse of central neurocytomas, the kinds of neuro transmitters in central neurocytomas have never been identified. In this st udy we analyzed neurotransmitters in an attempt to clarify the tumorigenesi s of central neurocytomas. We studied frozen central neurocytoma specimens from four patients. The tissue levels of glutamate and GABA (gamma -aminobu tyric acid) in the tumours were determined by gas chromatography-mass spect rometry (GC-MS) using a selected ion monitoring method. The tissue levels o f acetylcholine, choline, catecholamines and metabolites of catecholamines in the tumours were measured by high-performance liquid chromatography comb ined with electrochemical detection. Choline was found in extremely high co ncentration in all central neurocytomas when compared with levels in contro ls. In one central neurocytoma, GABA was found in extremely high concentrat ion compared with controls. In all central neurocytomas, glutamate was foun d in lower or identical concentrations compared with controls. In all centr al neurocytomas and controls, dopamine and catecholamine concentrations wer e extremely low. These results indicated that the histogenesis of central n eurocytomas begins with the subependymal stem cells, which have the potenti al to differentiate into cholinergic or GABA neurons.