adaptation alzheimer'sdisease alzheimerdisease brain chemotherapy cholinergic cholinergicmechanisms cholinergicreceptors cholinesteraseinhibitors congresses development drugeffects drugtherapy fibroblastgrowthfactors growth nervegrowthfactors nerveregeneration nerves nervoussystem neuralcircuitry neuronalplasticity neurons neuroplasticity neuroregulators neurotransmitteragents neurotrophicfunctions parasympathomimetics physiologicaleffect physiology receptors regeneration therapeuticuse wl102n2785n1987 wl300n49381731987 wm220c5471991 wm220g8841990