DISTRIBUTION AND EXPRESSION OF THE ALPHA-TUBULIN MESSENGER-RNA IN THEHIPPOCAMPUS AND THE TEMPORAL CORTEX IN ALZHEIMERS-DISEASE

The distribution of the messenger RNA for alpha-tubulin has been inves tigated by in situ hybridization in the human hippocampus and temporal cortex in normal subjects and in Alzheimer's disease. The alpha-tubul in mRNA was strongly expressed in neurons in the gyrus dentatus, in th e Ammon's horn and in cortical layers of the temporal cortex. The same distribution was observed in Alzheimer's disease. An important reduct ion of the hybridization signal was apparent, however, in areas rich i n neurofibrillary lesions, e.g. as in layer II of entorhinal cortex. N eurons containing neurofibrillary tangles exhibited a weaker hybridiza tion signal than adjacent neurons devoid of neurofibrillary tangles. T he immunoreactivity for alpha-tubulin was drastically reduced in tangl es-bearing neurons. These results indicate that tubulin transcription is reduced in tangles-bearing neurons, a reduction which might play a role in the reported decrease in the number of microtubules in neurons containing neurofibrillary tangles.