Dose-dependent effect of donepezil administration on long-term enhancement of visually evoked potentials and cholinergic receptor overexpression in rat visual cortex

Publication date: Available online 29 November 2016 Source:Journal of Physiology-Paris Author(s): Mira Chamoun, Marianne Groleau, Menakshi Bhat, Elvire Vaucher Stimulation of the cholinergic system tightly coupled with periods of visual stimulation boosts the processing of specific visual stimuli via muscarinic and nicotinic receptors in terms of intensity, priority and long-term effect. However, it is not known whether more diffuse pharmacological stimulation with donepezil, a cholinesterase inhibitor, is an efficient tool for enhancing visual processing and perception. The goal of the present study was to potentiate cholinergic transmission with donepezil treatment (0.5 and 1 mg/kg) during a 2-week visual training to examine the effect on visually evoked potentials and to profile the expression of cholinergic receptor subtypes. The visual training was performed daily, 10 min a day, for 2 weeks. One week after the last training session, visual evoked potentials were recorded, or the mRNA expression level of muscarinic (M1-5) and nicotinic (α/β) receptors subunits was determined by quantitative RT-PCR. The visual stimulation coupled with any of the two doses of donepezil produced significant amplitude enhancement of cortical evoked potentials compared to pre-training values. The enhancement induced by the 1 mg/kg dose of donepezil was spread to neighboring spatial frequencies, suggesting a better sensitivity near the visual detection threshold. The M3, M4, M5 and α7 ...
Source: Journal of Physiology Paris - Category: Physiology Source Type: research