Fig. 4.

Effect of streptozotocin (STZ)-treatment on M₂ receptor-mediated inhibition of relaxation in urinary bladder lacking urothelium. The effect of forskolin (5 µM) on oxotremorine-M-mediated contractile responses was measured in wild-type and M₂ KO bladders 2 to 3 weeks (a, b), 8 to 9 weeks (c–d), and 20 to 24 weeks (e–f) after STZ treatment. Open circles denote wild type, control; closed circles denote wild type in the presence of forskolin; open triangles denote M₂ KO, control; closed triangles denote M₂ KO in the presence of forskolin. Mean ± SEM values from three to seven experiments are indicated, each done on a separate bladder