GALANIN RECEPTOR-BINDING SITES IN THE TEMPORAL AND OCCIPITAL CORTEX ARE MINIMALLY AFFECTED IN ALZHEIMERS-DISEASE

Galanin receptor binding sites were examined in the inferior temporal and medial occipital gyri of patients with Alzheimer's disease (AD) an d matched control subjects using quantitative autoradiography. In the inferior temporal gyrus, galanin binding was reduced selectively in la yers V-VI of the AD cases compared to controls, the magnitude of the r eduction (45%) being similar to that of choline acetyltransferase acti vity (40%) in this region. In the medial occipital gyrus, galanin bind ing in the AD cases was not different from controls in any cortical la yer despite a reduction in choline acetyltransferase activity. Galanin binding did not correlate with the densities of neuritic plaques in e ither temporal or occipital gyri. Thus, despite a significant cortical cholinergic deficit in AD, there is an anatomically selective reducti on of cortical galanin receptor binding sites suggesting that the majo rity of galanin receptors are not located on cholinergic terminals in the human cerebral cortex.