Figure 2.

Single‐channel recordings as a function of ACh concentration for muscle and α7 nACh receptors. For the muscle nACh receptor, single‐channel activity appears as bursts separated from each other by relatively long silent periods in which the receptor is desensitized. Bursts are composed of successive opening events corresponding to the same individual channel. The main closed time within a burst reflects the transitions between unliganded closed and diliganded open states and becomes progressively briefer with increasing ACh concentration. In contrast, the temporal pattern of α7 channel currents does not show any concentration dependence due to the fact that desensitization determines the rate of channel closing. Channel activity appears as brief (~0.1 ms) isolated events. Openings are shown as upward deflections. C and O correspond to closed and open states respectively. Membrane potential: −70 mV. Filter: 9 kHz.