| 翻訳と辞書 |
Nav1.7
Nav1.7 is a sodium ion channel that in humans is encoded by the ''SCN9A'' gene. It is usually expressed at high levels in two types of neurons, the nociceptive (pain) neurons at dorsal root ganglion (DRG) and trigeminal ganglion, and sympathetic ganglion neurons, which are part of the autonomic (involuntary) nervous system.
== Function ==
Nav1.7 is a voltage-gated sodium channel and plays a critical role in the generation and conduction of action potentials and is thus important for electrical signaling by most excitable cells. Nav1.7 is present at the endings of pain-sensing nerves, the nociceptors, close to region where the impulse is initiated. Stimulation of the nociceptor nerve endings produces "generator potentials", which are small changes in the voltage across the neuronal membranes. The Nav1.7 channel amplifies these membrane depolarizations, and when the membrane potential difference reaches a specific threshold, the neuron fires. In sensory neurons, multiple voltage-dependent sodium currents can be differentiated by their voltage dependence and by sensitivity to the voltage-gated sodium-channel blocker tetrodotoxin. The Nav1.7 channel produces a rapidly activating and inactivating current which is sensitive to level of tetrodotoxin. Nav1.7 is important in early phases of neuronal electrogenesis. Nav1.7 is described by slow transition of the channel into an inactive state when it is depolarized, even to a minor degree. This property that allows these channels to remain available for activation with even small or slowly developing depolarizations. Stimulation of the nociceptor nerve endings produces "generator potentials", which is small changes in the voltage across the neuronal membranes. This brings neurons to certain voltage that stimulate Nav1.8, which has a more depolarized activation threshold that produces most of the transmembrane current responsible for the depolarizing phase of action potentials.
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「Nav1.7」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|