Dopamine in the body is a neurotransmitter that belongs to the class of catecholamines, which mainly has the function of transmitting nerve signals and regulating the function of the nervous system, and can be involved in various processes of information transmission. In addition, there is also a dopamine injection drug clinically available for the treatment of hypotension, as well as cardiogenic and central shock disorders. I. Neurotransmitters: Dopamine in vivo is a neurotransmitter secreted by the brain, which can act on many different dopamine pathways in the body to produce different effects.1. Nigro-striatal pathway: Dopamine can regulate muscle tone and maintain normal motor function of the body. If dopamine in this region decreases progressively, it can cause Parkinson’s disease, with symptoms such as resting tremor and motor retardation. 2. Midbrain-limbic pathway: dopamine is involved in the transmission of sensory information and is important for maintaining emotional stability and transmitting excitatory information. If dopamine in this region is increased, it may lead to schizophrenic symptoms such as fantasy and delusion. 3. Midbrain-cortical pathway: dopamine ensures the stability of higher brain functions, including logical thinking ability, judgment ability, and arithmetic analysis ability. If dopamine in this region is reduced, it may trigger adverse cognitive and emotional effects, such as emotional apathy and depression; 4. Nodal-funnel pathway: dopamine is also an important component in regulating endocrine function, such as increased secretion of prolactin when dopamine receptors are blocked. Second, the drug: dopamine injection is a cardiotonic drug, the injection will increase the excitability of alpha receptors, beta receptors, dopamine receptors, which in turn can play the role of vasodilatation, increase blood flow, and is commonly used in the clinical treatment of renal insufficiency, hypotension, heart failure, shock and other diseases.