Log concentration–response relaxation curves to (a, c) VIP and (b, d) PACAP 38 in pig intravesical ureter contracted to U46619 (0.1 μM), in control conditions and in the presence of ω-CgTX (1 μM) (a, b) or capsaicin (10 μM) (c, d). Relaxations are expressed as a percentage of the U46619-induced contraction. The results represent means and vertical lines s.e.m. of 6–8 preparations. *P<0.05 versus control value (paired t-test).