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

Abstract

Long-term chloroquine (CQ) intoxication of normal and groggy mutant rats resulted in transient accumulation of Gallyas-Braak (G-B) -positive and phosphorylated tau (AT8) -immunopositive substances in neuronal lipofuscin granules in the amygdala, hippocampus and entorhinal cortex. In the facial nuclei of normal rats, the neuronal lipofuscin granules were only AT8-immunopositive but G-B-negative, throughout CQ intoxication, while in groggy rats, the granules were positive by both staining methods irrespective of CQ intoxication. The results indicate that there are different mechanisms in the production of G-B-positive substances in neuronal lipofuscin granules between CQ-intoxicated rats and untreated groggy mutant rats.