Abstract
BACKGROUND: Current glioma grading schemes are limited by subjective histological criteria. Imidazoline I(2) receptors are principally expressed on glial cells. OBJECTIVE: To investigate the feasibility of using the measurement of imidazoline I(2) receptor expression to differentiate glial tumours from other types of brain tumours and for grading the different gliomas. METHODS: The specific binding of [(3)H]idazoxan to imidazoline I(2) receptors was measured in homogenates from human gliomas of different grades. RESULTS: The density of imidazoline I(2) receptors was significantly greater in the three types of malignant glial tumours than in postmortem control brain or non-glial tumours. The increase in density correlated with the malignancy grade of the gliomas. No significant differences in affinity values were observed. CONCLUSION: These results suggest that the density of imidazoline I(2) receptors may be a useful radioligand parameter for the differentiation of glial tumours from other types of brain tumours and for grading the different gliomas.