AMYLOID BETA-PROTEIN IMPAIRS ASTROCYTE-MEDIATED DIFFERENTIATION OF HIPPOCAMPAL-NEURONS

EMBRYONIC rat hippocampal neurons were cultured on poly-D-lysine (PDL) or on cortical astrocytes, some of which had been pretreated for 24 h with amyloid beta-protein (beta-AP). Amino acid-induced currents were quantified. Membrane capacitance (C-m), as well as the amplitude and density of amino acid-evoked currents recorded in neurons cultured on untreated astrocytes were all statistically greater than those recorde d in neurons grown on PDL. However, compared to untreated astrocytes, those treated with beta-AP led to significantly lower values in neuron s for C-m and GABA, kainate- and NMDA-induced currents, while glycine- activated current values were not significantly different. Furthermore , beta-AP treatment abolished spontaneous Ca-c(2+) fluctuations in ast rocytes, which may account for their impaired ability to promote the e xpression of functional transmitter receptors in neurons. NeuroReport 9: 3059-3063 (C) 1998 Lippincott Williams & Wilkins.