In this work a novel two-enzyme-two-compartment model is developed in order to explore the dynamics, bifurcation, and chaotic characteristics of the acetylcholine neurocycle. The model takes into consideration the physiological events of the choline uptake into the presynaptic neuron and choline release in the postsynaptic neuron. The effects of feed choline concentrations, feed acetate concentrations as bifurcation parameters are studied. It was found that feed choline concentrations play an important role and have a direct effect on the acetylcholine neurocycle through a certain important range of parameters. The feed acetate concentrations have less effect. A detailed bifurcation analysis over a wide range of parameters is carried out in order to uncover some important features of the system, such as static bifurcation, dynamic bifurcation and chaotic behavior. These findings are related to the real phenomena occurring in the neurons, like periodic stimulation of neural cells and non-regular functioning of acetylcholine receptors. The results are compared to the results of physiological experiments and other published models. As there is strong evidence that cholinergic brain diseases like Alzheimer's disease and Parkinson's disease are related to the concentration of acetylcholine, the present findings are useful for uncovering some of the characteristics of these diseases and encouraging more well-directed physiological research coupled to useful mathematical modeling. It is concluded from the results in this paper that feed choline is more important factor than feed acetate in ACh processes. (C) 2009 Elsevier Ltd. All rights reserved.