QUANTITATIVE AUTORADIOGRAPHY USING SELECTIVE RADIOLIGANDS FOR CENTRALAND PERIPHERAL-TYPE BENZODIAZEPINE RECEPTORS IN EXPERIMENTAL WERNICKES ENCEPHALOPATHY - IMPLICATIONS FOR POSITRON EMISSION TOMOGRAPHY IMAGING

Wernicke's encephalopathy (WE) is difficult to diagnose during life, w ith up to 80% of cases being missed by routine neurological evaluation in both alcoholics and AIDS patients. Therefore, there is a need for noninvasive diagnostic procedures. Using the pyrithiamine-treated rat, an animal model of WE, we have studied, using radioligands for centra l (neuronal) and ''peripheral-type'' (glial) benzodiazepine receptors, the regional distribution of changes in the densities of these recept ors in relation to the degree of reactive gliosis accompanying neurona l loss. Histological studies revealed neuronal loss in selective regio ns, including the thalamus, inferior colliculus, inferior olivary nucl eus, and mammillary body. Autoradiographic studies demonstrated increa ses in densities of [H-3]PK11195 binding sites that closely paralleled the topographic distribution of neuronal cell loss and reactive glios is. In contrast, [H-3]Ro15-178 showed poor spatial correlation, with t he neuronal loss seen in pyrithiamine-induced thiamine deficiency. The positron emission tomography ligand [C-11]PK11195 may be useful for t he assessment of thiamine deficiency-induced brain damage in human alc oholics.