乙酰胆碱是已知的第一种神经递质，它存在于人体的外周神经系统和中枢神经系统。这有激活位于躯体神经系统的骨骼肌的倾向，并与兴奋或抑制发生的神经肌肉连接处有很强的联系(Elias and Saucier, 2005)。这种神经递质可以在大脑的许多区域被发现。另一方面，多巴胺也存在于大脑中，但它有最大的力量来控制大脑的大部分功能。这将包括运动行为调节，情感唤起和其他形式的快乐。帕金森氏症患者体内多巴胺缺乏，而精神分裂症患者体内多巴胺含量较高。
乙酰胆碱影响肌肉活动，控制人的睡眠时间表。然而，多巴胺限制了大脑的运动区域，并使其暴露于震颤中(Lodish et al.， 2000)。
Acetylcholine is known to be the first neurotransmitter that is spotted in peripheral as well as central nervous system in the body. This has the tendency to activate the skeletal muscles located in somatic nervous system and strongly connected to the neuromuscular junction from where the excitement or inhibition happens (Elias and Saucier, 2005). This neurotransmitter can be spotted in many regions of brain. On the other hand, dopamine is also spotted in the brain, but it has the utmost power to control majority of the brain functions. This will include the motor behavior regulation, emotional arousal and other forms of pleasures. Those people suffering from Parkinson’s disease lack dopamine in them while those with schizophrenia have high dopamine in their bodies.
Acetylcholine acts as an excitatory neurotransmitter as well as inhibitory neurotransmitter but dopamine acts only as inhibitory neurotransmitter. As a result, the latter blocks the ability of neuron to fire and stays in the receptor sites. Dopamine becomes excitatory only during prolactin stimulation.
Acetylcholine influences the activities of muscles and controls the sleeping schedule of a person. However, dopamine restricts the motor areas of brain and exposes them to tremors (Lodish et al., 2000).
Dopamine affects the mood system of a person and the cognitive control is completely lost. There are internal sites where dopamine would control the motivation of a person and sexual arousal is also lost. The case is quite similar with acetylcholine system except the point that it exposes the person to wakefulness and short term memory is only affected.