Choline acetyltransferase and somatostatin levels in aged Microcebus murinus brain.

ABSTRACT

beta-Amyloid protein (beta-AP) deposits, analoguous to those found in Alzheimer's disease (AD) are observed in the brain of aging Microcebus murinus. Because choline acetyltransferase (ChAT) activity and somatostatin (SRIH) content are consistently decreased in AD, we tested whether such changes could be observed in middle aged to aged Microcebus cerebral cortex and whether they were accompanied by beta-AP deposits. A positive correlation was observed between age and ChAT activity. By HPLC, SRIH immunoreactivity eluted as four peaks, two of which being identical with SRIH-28 and SRIH-14 while the other two likely represented precursor forms. Cortical SRIH content was not significantly affected by age. ChAT activity and SRIH content were not significantly correlated. Amyloid angiopathy was observed in every brain examined and the presence of cortical lesions analoguous to senile plaques observed in the oldest case only which did not demonstrate important alterations in ChAT and somatostatin levels.