|
M current is a type of noninactivating potassium current first discovered in bullfrog sympathetic ganglion cells 〔BROWN, D. A. & ADAMS, P. R. (1980). Muscarinic suppression of a novel voltage-sensitive K+-current in a vertebrate neurone. Nature, Lond. 283, 673-676.〕 The ''M-channel'' is a voltage-gated K+ channel that is named after the receptor it is influenced by. The M-channel is important in raising the threshold for firing an action potential. It is unique because it is open at rest and even more likely to be open during depolarization. Furthermore, when the muscarinic acetylcholine receptor (MAChR) is activated, the channel closes. The M-channel is a PIP2-regulated ion channel. ==Actions of M-currents: "phasic-firing"== M-channels are the reason for slow depolarizations produced by ACh and LHRH in the autonomic ganglia and other specified areas. 1. Initial depolarization of a neuron increases likelihood that M-channels will open. 2. M-channels generate an outward potassium current (iK). 3. Potassium efflux counteracts sodium influx in action potential (AP). Overall result: full action potential is prevented. 〔 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「M current」の詳細全文を読む スポンサード リンク
|