Transient accumulation of Gallyas-Braak-positive and phosphorylated tau-immunopositive substances in neuronal lipofuscin granules in the amygdala, hippocampus and entorhinal cortex of rats during long-term chloroquine intoxication

Long-term chloroquine (CQ) intoxication of normal and groggy mutant rats re sulted in transient accumulation of Gallyas-Braak (G-B) -positive and phosp horylated tau (AT8) -immunopositive substances in neuronal lipofuscin granu les in the amygdala, hippocampus and entorhinal cortex. In the facial nucle i of normal rats, the neuronal lipofuscin granules were only AT8-immunoposi tive but G-B-negative, throughout CQ intoxication, while in groggy rats, th e granules were positive by both staining methods irrespective of CQ intoxi cation. The results indicate that there are different mechanisms in the pro duction of G-B-positive substances in neuronal lipofuscin granules between CQ-intoxicated rats and untreated groggy mutant rats.