Glibenclamide-sensitive and -insensitive components of the ZD6169-induced urethral relaxation. The dashed line indicates the mean resting urethral tone. (a), (b), (c) The effects of 1 μM glibenclamide on the relaxation induced by 3 μM, (a); 30 μM, (b); 100 μM, (c); ZD6169. (d) ZD6169 (100 μM)-induced relaxation after 11 min pretreatments with 1 μM glibenclamide.