Fig. 1.

In vitro kinetic and permeation properties of a panel of mutant mouse AChRs used in transgenic mice.A, Single-channel recordings (left) and open duration histograms (right) for mouse wild-type and AChR mutants expressed in Xenopus oocytes. Recordings were performed at −100 mV and 2.0 μm ACh. Marquardt least squares fitting in pClamp 6 allowed resolution of two open components for each mutant (Table 1). B, Single-channel conductance obtained from oocyte patch-clamp recordings. There is no significant difference between the conductance for sodium among any of the mutants. C, Permeability of wild-type and mutant AChRs to calcium relative to sodium. The relative calcium permeability of αL251T (n = 17) AChRs is ∼33% greater than wild-type AChRs (n = 19;p < 0.005). The relative calcium permeability of δS262T AChRs (n = 20) is ∼67% less than wild type (p < 0.001).