Protective effect of donepezil in primary-cultured rat cortical neurons exposed to N-methyl-D-aspartate (NMDA) toxicity

Donepezil has a neuroprotective effect against oxygen-glucose deprivation injury and glutamate toxicity in cultured cortical neurons. In this study, we further characterized the neuroprotective properties of donepezil in rat cortical cell cultures using glutamate receptor-specific agonists (N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methylisoxazoleproponate (AMPA) and kainate). Pretreatment with donepezil (1 mu M) for 12 h significantly decreased the lactate dehydrogenase (LDH) release in response to NMDA (100 mu M) by 43.8%, and reduced the LDH release in response to kamate (100 mu M) and AMPA (100 mu M) by 11.9% and 7.5% (without statistical significance), respectively. Donepezil appeared to inhibit LDH release in a concentration-dependent manner at 0.1 - 10 mu M. Cortical neurons exposed to NMDA retained a normal morphological appearance in the presence of 10 mu M donepezil. In binding assay for glutamate receptors, donepezil at 100 mu M only slightly inhibited binding to the glycine and polyamine sites on NMDA receptor complex. On the other hand, 12 h pretreatment with donepezil at 10 and 100 mu M significantly decreased the NMDA-induced increase of intracellular calcium concentration ([Ca2+](i)). In conclusion, our results show that donepezil has protective activity against NMDA toxicity in cortical neurons, and this neuroprotection seems to be partially mediated by inhibition of the increase of [Ca2+](i). (c) 2005 Elsevier B.V. All rights reserved.