*A*, results of simultaneous fitting of rate constants to the same three wild type patches shown in (50 nm, 100 nm and 10 μm ACh respectively, left to right), unconstrained estimations of forward rates with scheme 2 resulted in unrealistically fast forward rates, consequently one of the forward rates in the fits shown was constrained by the EC_{50}. Top row, apparent open times, second row, apparent shut times. The solid lines in each case show the predicted HJC distribution calculated from the estimation of rate constants from all three patches simultaneously, superimposed on the histogram of experimentally observed events for each patch in turn. The dashed lines show the predicted ideal distributions. Third row, conditional HJC distributions (solid lines) of apparent open times adjacent to shut times in the range *t* < 0.1 ms superimposed on the experimentally observed open times adjacent to shut times in the same range. The dashed lines show the HJC distributions of all apparent open times. Bottom row, conditional distributions of mean open time adjacent to specified shut time ranges plotted against apparent shut time. The solid lines show the observed correlation from experimental data, the dashed lines show the predicted correlation calculated from the rate constants by HJCFIT. The arrow indicates the *t*_{crit} for each patch, experimentally observed shut times greater than this value will be underestimated as we do not know the number of channels in the patch and they are shown for illustrative purposes only. *B*, as *A* but shows the results of simultaneous fitting of rate constants to the same three εL221F patches shown in (100 nm, 1 μm and 10 μm ACh respectively, left to right), again with one of the forward rates constrained by the EC_{50} as for wild type data. *C*, as *B* but shows the results of fitting the same three εL221F patches with the binding and unbinding rates for the *b* site fixed to the mean wild type values, the remaining forward rates were constrained by the EC_{50}.

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