Nicotinic Acetylcholine Receptor-Mediated Neuroprotection by Donepezil Against Glutamate Neurotoxicity in Rat Cortical Neurons

Abstract

Donepezil is a potent and selective acetylcholinesterase (AChE) inhibitor developed for the treatment of Alzheimer's disease. To elucidate whether donepezil shows neuroprotective action in addition to amelioration of cognitive deficits, we examined the effects of donepezil on glutamate-induced neurotoxicity using primary cultures of rat cortical neurons. A 10-min exposure of cultures to glutamate followed by a 1-h incubation with glutamatefree medium caused a marked loss of viability, as determined by Trypan blue exclusion. Glutamate neurotoxicity was prevented by 24-h pretreatment of donepezil in a concentration-dependent manner. Among AChE inhibitors examined, donepezil and certain AChE inhibitors such as tacrine and galanthamine showed potent neuroprotective action, although physostigmine did not affect glutamate neurotoxicity. Neuroprotective action of donepezil was antagonized by mecamylamine, a nicotinic acetylcholine receptor (nAChR) antagonist, but not by scopolamine, a muscarinic acetylcholine receptor antagonist. Furthermore, both dihydro-␤-erythroidine, an ␣4␤2-neuronal nAChR antagonist, and methyllycaconitine, an ␣7-nAChR antagonist, each also significantly antagonized the effect of donepezil. Next, we examined the effects of donepezil on glutamate-induced apoptosis. Exposure of 100 M glutamate to cortical neurons for 24 h induced apoptotic neuronal death and nuclear fragmentation. Donepezil for 24 h before and 24 h during glutamate exposure prevented nuclear fragmentation and glutamate-induced apoptosis. These results suggest that donepezil not only protects cortical neurons against glutamate neurotoxicity via ␣4␤2-and ␣7-nAChRs but also prevents apoptotic neuronal death.

Donepezil, an acetylcholinesterase inhibitor against Alzheimer's dementia, promotes angiogenesis in an ischemic hindlimb model

“…Donepezil was developed to treat patients with Alzheimer's disease as an acetylcholinesterase inhibitor [12,13]. Donepezil prevents neurons from apoptosis and degeneration [19][20][21][22] and improves cognitive abilities in patients with Alzheimer's disease [23][24][25]. However, only few studies have focused on the angiogenesis accelerating effects of donepezil [26].…”

Donepezil, Therapeutic Acetylcholinesterase Inhibitor, Prevents the Progression of Ventricular Dysfunction by Promoting Myocardial Glucose Utilization in Rat Model of Chronic Heart Failure Following Myocardial Infarction

“…The non-neuronal cholinergic system might also be involved in efficient glucose metabolism in cardiomyocytes. Additionally, a number of experimental studies strongly suggest that donepezil directly affect cells via a mechanism that is independent of its pharmacological action of acetylcholinesterase inhibition [19,[47][48][49]. Further investigation is needed to determine the molecular mechanism of the donepezil-induced increase in the efficiency of cardiac glucose utilization.…”

“…After medium was replaced with fresh conditioned Dulbecco's Modified Eagle Medium (DMEM, Wako Pure Chemical Industries, Lt., Osaka, Japan) with or without donepezil at a concentration of 10 µM, cells were further incubated at 37°C for 2-3 days. The concentration of donepezil was determined by referring to Takada et al who investigated the cell protective properties of donepezil [19]. mRNA or protein was obtained from the cultured cardiomyocytes for reverse transcription-polymerase chain reaction (RT-PCR) or Western blot analysis, respectively.…”

Neuroprotective Effects of Citidine-5-diphosphocholine on Impaired Spatial Memory in a Rat Model of Cerebrovascular Dementia

“…Donepezil powerfully inhibits acetylcholinesterase (17) and elevates acetylcholine concentration in the synapse, which results in increased cholinergic transmission. Previous studies have suggested the donepezil has neuroprotective effects aside from its acetylcholinesterase-inhibiting action through up-regulation of Bcl-2, an anti-apoptotic protein (18), stimulation of nicotinic acetylcholine receptors (19), and inhibition of glycogen synthase kinase-3 (GSK-3) activity (20). It is unknown whether donepezil exerts its neuroprotective effect in rats subjected to repeated cerebral ischemia.…”

“…It is unknown whether donepezil exerts its neuroprotective effect in rats subjected to repeated cerebral ischemia. Induction of the neuroprotective effects of donepezil via the nicotinic acetylcholine receptor in rats subjected to repeated cerebral ischemia may require a higher concentration and/or long-term treatment because the concentration of donepezil showing neuroprotection is higher than the concentration needed to exhibit acetylcholinesterase-inhibiting action in vitro (17,19,20).…”