Figure 1.
Representative whole-cell cation current response to 50 μM carbachol application (a) recorded at −40 mV. Examples of the 140 pS channel activity at −80 and 80 mV in an outside-out membrane patch, formed at the maximal whole-cell response to the agonist are shown in the inset. In a membrane patch from a different cell (b) activity of 17 and 74 pS MRCC is evident; see also the all-point amplitude histogram shown in (c). The dotted lines in all figures indicate the current levels corresponding to the open (O) and closed (C) channel states. Holding potential was −40 mV. Calculated current amplitudes and open probabilities were −0.72±0.09 pA, Po=0.03 and −2.98±0.14 pA, Po=0.24 for the small and medium conductance channels, respectively.