A POTENTIAL USE OF A I-123 LABELED BENZODIAZEPINE RECEPTOR ANTAGONIST AS A PREDICTOR OF NEURONAL CELL VIABILITY - COMPARISONS WITH C-14-LABELED 2-DEOXYGLUCOSE AUTORADIOGRAPHY AND HISTOPATHOLOGICAL EXAMINATION

In the treatment and therapy of patients suffering a stroke, it is very important to predict whether viable neurones, even those of poor function, remain intact in the lesions of the brain. To determine whether viable neurones of low functional activity are represented in in vivo neuroreceptor imaging, we undertook experiments in gerbils with cerebral infarction, in which we examined histological changes and the results of dual-tracer in vivo autoradiography of glucose utilization with C-14-labelled deoxyglucose and benzodiazepine receptor binding with I-123-labelled Ro 16-0154. The unrelated findings of cerebral glucose metabolism and benzodiazepine receptor binding were observed in the primary infarct lesion and in remote areas, including the ipsilateral striatum and thalamus. Our experiments showed that when viable neurones with low functional activity remain intact, normal in vivo binding to benzodiazepine receptors is demonstrated as hypometabolism of glucose utilization. This functional, contrast-enhanced technique with I-123-labelled Ro 16-0154 may have an important role to play in the prediction of neuronal cell viability after recent brain infarction in experimental animals and humans using single photon emission tomography (SPET).