Figure 1.

Outflow of tritium from urinary bladder pieces taken from NMRI (A), M₂-wildtype (B), M₄-wildtype (C), M₂-knockout (D) or M₄-knockout mice (E): effects of electrical stimulation and carbachol. After preincubation with ³H-noradrenaline tissues were superfused and stimulated electrically six times by 20 pulses/50 Hz (S₁ to S₆). Filled circles, controls (no carbachol). Empty circles, carbachol was added at increasing concentrations as indicated. Each line represents the mean of three to 13 bladder pieces.