Editing Excitatory synapse (section)

{{short description|Sort of synapse}}
[[File:SynapseSchematic en.svg|thumb|A diagram of a typical [[central nervous system]] synapse. The spheres located in the upper neuron contain [[neurotransmitter]]s that fuse with the [[presynaptic membrane]] and release neurotransmitters into the [[synaptic cleft]]. These neurotransmitters bind to receptors located on the [[postsynaptic membrane]] of the lower neuron, and, in the case of an excitatory synapse, may lead to a [[depolarization]] of the postsynaptic cell.]]

An '''excitatory synapse''' is a [[synapse]] in which an [[action potential]] in a [[presynaptic neuron]] increases the probability of an [[action potential]] occurring in a postsynaptic cell. Neurons form networks through which nerve impulses travels, each neuron often making numerous connections with other cells of neurons.  These electrical signals may be excitatory or inhibitory, and, if the total of excitatory influences exceeds that of the inhibitory influences, the neuron will generate a new [[action potential]] at its [[axon hillock]], thus transmitting the information to yet another cell.<ref name="Annual Review of Biochemistry">{{Cite journal|title=The Postsynaptic Architecture of Excitatory Synapses: A More Quantitative View |journal=Annual Review of Biochemistry |volume=76 |pages=823–47 |author1-link=Morgan Sheng |author1=M. Sheng |author2=C. Hoogenraad |year=2006|doi=10.1146/annurev.biochem.76.060805.160029 |pmid=17243894 |author2-link=Casper Hoogenraad }}</ref>

This phenomenon is known as an [[excitatory postsynaptic potential]] (EPSP).  It may occur via direct contact between cells (i.e., via [[gap junction]]s), as in an [[electrical synapse]], but most commonly occurs via the [[vesicle (biology and chemistry)|vesicular]] release of [[neurotransmitter]]s from the [[presynaptic]] [[axon terminal]] into the [[synaptic cleft]], as in a [[chemical synapse]].<ref name="Journal of Cell Science">{{cite journal |title=Architecture of an Excitatory Synapse |journal=Journal of Cell Science |volume=123 |issue=6 |pages=819–823 |author1=Chua, Kindler |author2=Boykin, Jahn |date=2010-03-03|doi=10.1242/jcs.052696 |pmid=20200227 |hdl=11858/00-001M-0000-0012-D5F7-3 |s2cid=13491894 |hdl-access=free }}</ref>

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.<ref name="Annual Review of Biochemistry"/>   Depolarization, a deviation from a neuron's [[Resting potential|resting membrane potential]] towards its [[threshold potential]], increases the likelihood of an action potential and normally occurs with the influx of positively charged [[sodium]] (Na<sup>+</sup>) ions into the postsynaptic cell through [[ion channel]]s activated by neurotransmitter binding.