![]() There are two types of synapses, electrical and chemical synapses, but chemical synapses ( Figure 2) far outnumber electrical ones. Thus, there are 3–5 × 10 15 synapses in the human brain. The number of synaptic contacts of an average neuron is approximately 10,000. The secreted neurotransmitters can then act on receptors on the membrane of the postsynaptic neuron through a gap called synaptic gap (0.02 micron). The neurotransmitters are stored in the vesicles within the presynaptic nerve terminal at the synaptic membrane of one nerve cell and released into the synaptic cleft in response to nerve impulses. The process by which the information is communicated through synapse is called synaptic transmission. Synapses are specialized junctions through which cells of the nervous system signal to one another and to non-neuronal cells such as muscles or glands. The release of neurotransmitter is triggered by the arrival of nerve impulse (or action potential). Neurotransmitters are stored in the axon (or presynaptic neuron) in little packages called synaptic vesicles. ![]() Neurotransmitters are chemical substances that act as the mediator for the transmission of nerve impulses from one neuron to another neuron through synapses. Efficient communication between neuronal cells is a crucial process for the normal functioning of the central and peripheral nervous system. In its most basic form, a neuron has two ends (although either can have multiple branches): an axon and a dendrite ( Figure 1). Neurons are the cells of chemical communication in the brain. The nervous system is composed of billions of specialized cells called neurons. The presynaptic and postsynaptic events in chemical synapses are subject to use dependent and highly regulated as per the changes in synaptic neurotransmitter release and function. The integral role of amino acid neurotransmitters is important on the normal functioning of the brain. Amino acid neurotransmitters primarily glutamic acid, GABA, aspartic acid, and glycine are single amino acid residues released from presynaptic nerve terminals in response to an action potential and cross the synaptic cleft to bind with specific receptor on the postsynaptic membrane. Through synaptic transmission, this information is communicated from the presynaptic cell to the postsynaptic cell. The balance of glutamatergic and GABAergic tone is crucial to normal neurologic function. Glutamate is the primary excitatory neurotransmitter in the brain, while GABA is the principal inhibitory neurotransmitter. The process of synaptic transmission generates or inhibits electrical impulses in a network of neurons for the processing of information. Chemical and electrical synapses are specialized biological structures found in the nervous system they connect neurons together and transmit signals across the neurons. Neurotransmitters are synthesized and stored in presynaptic terminals, released from terminals upon stimulation with specific receptors on the postsynaptic cells. Amino acids are the most abundant neurotransmitters in the brain.
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