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In neuroscience, synaptic scaling (or homeostatic scaling) is a form of homeostatic plasticity that allows single neurons to regulate their overall action potential firing rate. Like many other physiological systems, neural electrochemical activity is subject to homeostasis. Where Hebbian plasticity mechanisms modify neural synaptic connections selectively, synaptic scaling works in unison with other homeostatic plasticity mechanisms to normalize all neural synaptic connections. ==Cellular components involved in synaptic scaling== # (Chemical) Synaptic connection: At chemical synapses, pre-synaptic neurons release vesicles containing neurotransmitters into the synaptic cleft. The extracellular neurotransmitters then interact with particular post-synaptic transmembrane protein receptors to allow a fraction of the neurotransmitters into the post-synaptic neuron. # Pre-synaptic vesicles : Vesicles are the means of chemical-synaptic plasticity. Pre-synaptic neurons relay information (in the form of neurotransmitters) to post-synaptic neurons via vesicles. The neurotransmitters inside vesicles are transported to the synaptic cleft where they interact with neurotransmitter specific post-synaptic protein receptors. # Glutamate: Glutamate is the primary excitatory neurotransmitter within vertebrates and plays a large role in synaptic plasticity. Stimulus to the pre-synaptic neurons triggers glutamate release into the synaptic cleft via pre-synaptic vesicle release. Once in the synaptic cleft, glutamate can bind and activate post-synaptic glutamatergic protein receptors such as NMDA and AMPA receptors. # Post-synaptic AMPA receptor: AMPA Receptors are trans-membrane protein ionotropic receptors that open and close quickly and are responsible for fast excitatory synaptic communication in the Central Nervous System. AMPA receptors have four subunits that glutamate can bind to. Depending on the AMPA receptor subunit compositions, the receptor can be permeable to cations such as calcium, sodium, or potassium 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Synaptic scaling」の詳細全文を読む スポンサード リンク
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