Glutamate
The excitatory neurotransmitters, the most common of which is glutamate, then migrate via diffusion to the dendritic spine of the postsynaptic neuron and bind a specific transmembrane receptor protein that triggers the depolarization of that cell. When neurotransmitters reach the postsynaptic neuron of an excitatory synapse, these molecules can bind to two possible types of receptors that are clustered in a protein-rich portion of the postsynaptic cytoskeleton called the Postsynaptic density (PSD). Nerve cells communicate messages by secreting neurotransmitters. Neurotransmitters can excite or inhibit neurons (nerve cells). Some common neurotransmitters are acetylcholine, norepinephrine, dopamine, serotonin and gamma aminobutyric acid (GABA). Acetylcholine and norepinephrine are excitatory neurotransmitters while dopamine, serotonin, and GABA are inhibitory. Each neurotransmitter can directly or indirectly influence neurons in a specific portion of the brain, thereby affecting behavior.  There are many types of neurotransmitters in the brain—what they have in common is that they are produced inside a neuron, released into the synapse, and then cause an excitatory or inhibitory effect on receptor cells, helping to propagate or downgrade action potentials.  Neurotransmitters and Neuroactive Peptides. Communication of information between neurons is accomplished by movement of chemicals across a small gap called the synapse. Chemicals, called neurotransmitters, are released from one neuron at the presynaptic nerve terminal. Dopamine, norepinephrine and epinephrine are a group of neurotransmitters called catecholamines. Norepinephrine is also called noradrenalin and epinephrine is also called adrenalin. Each of these neurotransmitters is produced in a step-by-step fashion by a different enzyme. Neurotransmitters are endogenous chemicals that enable neurotransmission. They transmit signals across a chemical synapse, such as in a neuromuscular junction, from one neuron (nerve cell) to another target neuron, muscle cell, or gland cell. Neurotransmitters are released from synaptic vesicles in synapses into the synaptic cleft, where they are received by receptors on other synapses. Neurotransmitters are released into and diffused across the synaptic cleft, where they bind to specific receptors in the membrane on the postsynaptic side of the synapse. Most neurotransmitters are about the size of a single amino acid, however, some neurotransmitters may be the size of larger proteins or peptides. In a typical chemical synapse between two neurons, the neuron from which the nerve impulse arrives is called the presynaptic neuron. The neuron to which the neurotransmitters (chemical messengers) bind is called the postsynaptic neuron. GABA (gamma-aminobutyric acid) is an inhibitory neurotransmitter that is very widely distributed in the neurons of the cortex. GABA contributes to motor control, vision, and many other cortical functions. It also regulates anxiety. NEUROTRANSMITTERS are the brain chemicals that communicate information throughout our brain and body. They relay signals between nerve cells, called “neurons.” The brain uses neurotransmitters to tell your heart to beat, your lungs to breathe, and your stomach to digest. SEROTONIN is an inhibitory neurotransmitter – which means that it does not stimulate the brain. Adequate amounts of serotonin are necessary for a stable mood and to balance any excessive excitatory (stimulating) neurotransmitter firing in Inhibitory Neurotransmitters. SEROTONIN is an inhibitory neurotransmitter – which means that it does not stimulate the brain. Adequate amounts of serotonin are necessary for a stable mood and to balance any excessive excitatory (stimulating) neurotransmitter firing in the brain.
https://en.wikipedia.org/wiki/Excitatory_synapse http://www.minddisorders.com/Kau-Nu/Neurotransmitters.html http://www.dana.org/News/Details.aspx?id=43536 https://faculty.washington.edu/chudler/chnt1.html https://en.wikipedia.org/wiki/Neurotransmitter http://thebrain.mcgill.ca/flash/i/i_01/i_01_m/i_01_m_ana/i_01_m_ana.html https://www.neurogistics.com/TheScience/WhatareNeurotransmi09CE.asp https://www.neurogistics.com/TheScience/WhatareNeurotransmi09CE.asp
common chemical neurotransmitters