Neuronel Signaling Pathway

Neurons are the most basic structural and functional units of the nervous system, which are divided into two parts: cell bodies and processes. The cell body is composed of the nucleus, the cell membrane, and the cytoplasm, which has the function of connecting and integrating input information and efferent information. There are two types of processes: dendrites and axons. Dendrites are short and branched, which are directly expanded from the cell body to form dendrites. Their role is to receive impulses from the axons of other neurons and transmit them to the cell body. Axons are long and sparsely branched, slender processes of uniform thickness, often arising from the axon hilum, and their role is to receive foreign stimuli and then efferent from the cell body. In addition to branching off collaterals, axons form dendritic nerve endings at their ends. The terminals are distributed in some tissues and organs to form various nerve terminal devices. Synaptic transmission is one of the important modes of neural signal transmission. Neurotransmitters are released from the presynaptic membrane and immediately bind to the corresponding postsynaptic membrane receptors, resulting in synaptic depolarization potential or hyperpolarization potential, resulting in an increase or decrease in postsynaptic nerve excitability. The action of neurotransmitters can be terminated through two pathways: one is recycling inhibition, in which the excess neurotransmitters in the synaptic cleft are recovered to presynaptic neurons and stored in vesicles by the action of presynaptic carriers; The other pathway is enzymatic hydrolysis. In the case of dopamine (DA), it is metabolized and inactivated by the action of monoamine oxidase (MAO) in the mitochondria and catecholamine o-methyltransferase (COMT) in the cytoplasm. When the corresponding receptor receives the information carried by the transmitter and other information transmitters, the reaction is either directly given by the ion channel, or transmitted to the effector molecule through the transductor called G protein to give the reaction. G protein-coupled receptors (GRCR) are activated by a variety of stimuli, and its downstream signaling pathways include 5-HT, histamine, cholinergic, GABA, etc. Therefore, G protein-coupled receptors are important therapeutic targets in many nervous system diseases and can be used for therapeutic intervention in a variety of different central nervous system diseases, including stroke, Alzheimer’s disease, and central nervous system tumors.