Donepezil HCl(Aricept) is a selective and effective AChE inhibitor for bAChE and hAChE (IC50: 8.12/11.6 nM).

AChE (human):11.6 nM, AChE (bovine):8.12 nM

Donepezil inhibits the carbachol-stimulated increase in intracellular Ca2+ concentration in human SHSY5Y neuroblastoma cells in a concentration dependent manner, indicating that Donepezil have muscarinic antagonist activity. [2] A recent study shows that Donepezil can protect human umbilical vein endothelial cells (HUVECs) against Water2-induced cell injury. This may be useful as a potential therapy for oxidative stress in cardiovascular and cerebrovascular diseases. [3]

Intraperitoneal administration of Donepezil in rats produces a dose dependent increase in salivation and tremor, which are overt cholinergic behavioural signs, with an ED50 of 6 μmol/kg. Donepezil is found to be somewhat less potent with a ED50 of 50 μmol/kg following oral administration. [2]. When administered separately in vivo, 5-HT(4) receptor inducer, RS67333 (0.3 and 1 mg/kg) and Donepezil (1 mg/kg) improves recognition performances compared to saline treated mice, while co-administration of subactive doses of RS67333 (0.1 mg/kg) and Donepezil (0.3 mg/kg) improves memory. However, this improvement is prevented if a 5-HT(4)R antagonist (GR125487, 10 mg/kg) is also administered. [4]

[3H]-Pyrilamine binding to histamine (H1) receptors in guinea pig cerebellum membranes.: Antagonists are incubated with guinea pig cerebellum membranes (0.6 mg/ml) and [3H]-pyrilamine (1.2 nM) in 0.5 ml 50 mM PBS, pH 7.5, for 30 min at 25 ℃. The incubation is ended by the addition of 5 ml of ice-cold PBS containing 2 μM pyrilamine and the collection of membranes on Whatman GF/B filters. Then the filters are washed with 3 × 5 ml of ice-cold PBS plus 2 μM pyrilamine and transferred to counting vials. The radioactivity retained by each filter is measured by liquid scintillation counting in 3 ml of HiSafe 3. Specific binding is determined from the difference between the [3H]-pyrilamine bound in the absence and in the presence of a large molar excess (10 μM) of unlabeled promethazine.