title: Endogenous acetylcholine rescues NMDA-induced long-lasting hippocampal cell damage via stimulation of muscarinic M(1) receptors: elucidation using organic hippocampal slice cultures.
abstract: This study aimed to investigate a recuing role of cholinergic systems in the excitotoxicity-induced hippocampal cell damage. Organotypic hippocampal slice cultures (OHSCs) were prepared from 7-day-old mice and exposed to N-methyl-d-aspartate (NMDA) for 24h. After washing out the NMDA, OHSCs were incubated in medium containing test drugs for 0-6 days. Hippocampal cell damage was evaluated by propidium iodide staining, immunofluorescence, and Western blotting. NMDA (1-10 μM) dose-dependently damaged hippocampal cells. The toxic effect of 3 μM NMDA was also observed at 3-6 days, even after washing out NMDA, and was blocked by MK-801 from day 3 to day 6. Post-treatments with tacrine, donepezil, and galantamine reduced the NMDA-induced long-lasting hippocampal cell damage. The effect of tacrine was induced in a manner dependent on the incubation period after NMDA treatment and was confirmed by Nissl staining and immunostaining with NeuN, a marker of mature neurons. The effect of tacrine was attenuated by scopolamine and a muscarinic M(1) receptor antagonist, pirenzepine, but not by a muscarinic M(3) receptor antagonist, darifenacin, or a nicotinic receptor antagonist, mecamylamine. The protein kinase C inhibitor Ro-31-8220 abolished the effect of tacrine. The pretreatment with 3 μM NMDA had no effect on the expression level of presynaptic cholinergic markers, choline acetyltransferase and vesicular acetylcholine transporter, in OHSCs. These results suggest that a low concentration of NMDA causes long-lasting hippocampal cell damage and that endogenous acetylcholine plays, via muscarinic M(1) receptor, a rescuing role in the excitotoxicity-induced long-lasting hippocampal cell damage.
authors.affiliation: Division of Medicinal Pharmacology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Inada
authors.forename: Xoan
authors.initials: X
authors.lastname: Thi Le
authors.forename: Koichi
authors.initials: K
authors.lastname: Tsuneyama
authors.forename: Hironori
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Takeshi
authors.initials: T
authors.lastname: Miyata
authors.forename: Kinzo
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D000077265:Donepezil; D004305:Dose-Response Relationship, Drug; D005455:Fluorescent Antibody Technique; D005702:Galantamine / Q000494:pharmacology; D006624:Hippocampus / Q000473:pathology*; D007189:Indans / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D016202:N-Methylaspartate / Q000008:administration & dosage* / Q000378:metabolism; D009924:Organ Culture Techniques; D010880:Piperidines / Q000494:pharmacology; D043643:Receptor, Muscarinic M1 / Q000378:metabolism*; D013619:Tacrine / Q000494:pharmacology
chemical_list: D002800:Cholinesterase Inhibitors; D007189:Indans; D010880:Piperidines; D043643:Receptor, Muscarinic M1; D005702:Galantamine; D013619:Tacrine; D016202:N-Methylaspartate; D000077265:Donepezil; D000109:Acetylcholine