EXPRESSION OF CATALYTIC TRKB GENE IN THE STRIATUM AND THE BASAL FOREBRAIN OF PATIENTS WITH ALZHEIMERS-DISEASE - AN IN-SITU HYBRIDIZATION STUDY

The expression of catalytic trkB gene, encoding for the high affinity brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5) receptor, was studied post mortem in the striatum and the nucleus bas alis of Meynert of patients with Alzheimer's disease (AD) and control subjects, using in situ hybridization coupled with choline acetyltrans ferase immunohistochemistry. Microscopic examination of tissue section s showed labelling on perikarya of neurons but no labelling on glial c ells. In the striatum, cholinergic as well as non-cholinergic and, pre sumably GABAergic, neurons expressed detectable levels of TrkB mRNA, w hile in the nucleus basalis of Meynert, only cholinergic neurons were labelled. Quantitative analysis of the in situ hybridization signal in cells of these two regions failed to demonstrate any significant diff erence between AD patients and control subjects. Normal levels of TrkB mRNA in the surviving cholinergic neurons of the nucleus basalis of M eynert suggest that these neurons could respond to an exogenous supply of BDNF and/or NT-4/5. (C) 1997 Elsevier Science Ireland Ltd.