Functional expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors precedes the development of cholinergic phenotype in embryonic rat septal cells in culture

We examined the development of cholinergic neuronal functions and alpha-ami no-3-hydroxy-6-methyl-4-isoxazole propionic acid (AMPA) responses in cultur ed embryonic rat septal cells. Choline acetyltransferase activity was incre ased from 4 to 6 days in culture and reached a plateau at day 8. Acetylchol ine release was increased from 6 to 8 days in culture. AMPA-induced increas e in intracellular Ca2+ level was observed at 3 days in culture and most of the AMPA-responsive cells coincided with high-K+ responsive cells. These r esults suggest that cholinergic neurons develop their neuronal functions ab out 8 days under cultured conditions, and functional expression of AMPA rec eptors precedes the cholinergic functional development. (C) 2001 Published by Elsevier Science Ireland Ltd.