Membrane potential inward rectifier channels

Inward Rectification refers to decreased conductance upon membrane depolarization. In classical inward rectifier K+ channels, rectification is strong and currents rapidly decline at membrane potentials positive to the reversal potential, in contrast to other Kir channels in which rectification is weak and currents decline only gradually at potentials positive to the reversal potential. 

In many channels the relation between current and membrane potential is nonlinear. These channels show rectification, i.e., the property of the channel to conduct ions more readily in one direction than in the other. Depending on the preferential current flow through channels, these are described as outward or inward rectifying. 

The inward rectifier (Kjr or/ri) K" channel can be described mathematically with a single gate that operates so fast (usually less than a ms) that gRi can be treated as changing instantaneously with voltage since channels close with depolarisation, there is in effect a very strong inward rectification. The inward rectification of these channels tends to hold the resting membrane potential close to Vr. These channels... 

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