Figure 2. Chimeric AChRs with exchanged M3–M4 cytoplasmic loops between γ‐ and ε‐subunits.

A, chimeric γ‐subunits (blue) with ε‐M3–M4 cytoplasmic loop (orange) and chimeric ε‐subunits (orange) with γ‐M3–M4 cytoplasmic loop (blue). Both M3–M4 loops differ at 94/146 positions. A, mean weighted current decay time constants were 265 ± 72 ms in chimeric fetal (n = 10) and 237 ± 23 ms in chimeric adult (n = 10) AChRs. C, mean recovery time constants were 1419 ± 174 ms in chimeric fetal (n = 10) and 2022 ± 188 ms in chimeric adult (n = 10) AChRs. In two cells expressing chimeric fetal AChRs, recovery from desensitization was markedly faster. After exclusion of these two cells, the mean recovery time constant remained faster in chimeric fetal AChRs (1634 ± 121 ms, n = 8), although the difference compared to chimeric adult AChRs was no longer significant (t ₁₆ = 1.64, P = 0.1215). There was no obvious explanation for the markedly faster recovery from desensitization in the two cells in (C). Data represent the mean ± SEM. [Color figure can be viewed at wileyonlinelibrary.com]