1996l-901 2000f-775 alzheimer'sdisease alzheimerdisease chemotherapy cholinergic cholinergicmechanisms cholinergicreceptors cholinesterases drugeffects drugtherapy molecularaspects nervegrowthfactor neuroregulators neurotransmitteragents parasympathomimetics qv124c54722000 receptors therapeuticuse therapy treatment wm220c5471991 wt155a478811997