Single ion channels

The movie shows channels opened by a low concentration of acetylcholine. Openings are the downward deflections. Each opening has much the same amplitude, about 6 pA, but the durations of open and shut times are very variable, as expected for a single molecule. Analysis of the open and shut times can tell us the rates of transition between different states of the channel, and hence the equilibrium constants. Analysis of records like this can separate the binding steps from the opening steps, and hence solve the binding-gating problem (the affinity-efficacy problem).
The details. Human recombinant muscle type adult nicotinic receptor, , expressed in HEK cell, -100 mV. 100 nM ACh., cell-attached recording

[@sureshkumar-kx2xz]

wow! It such a pleasure to watch single channels in action