Kv7 channels are involved in smooth muscle relaxation, and accordingly we believe that they constitute potential targets for the treatment of overactive bladder syndrome. We have therefore used myography to examine the function of Kv7 channels in detrusor, i.e. pig bladder, with a view to determining the effects of the following potassium channel activators: ML213 (Kv7.2/Kv7.4 channels) and retigabine (Kv7.2-7.5 channels). Retigabine produced a concentration-dependent relaxation of carbachol- and electric field-induced contractions. The potency was similar in magnitude to that of ML213-induced relaxation, suggesting that Kv7.2 and/or Kv7.4 channels constitute the subtypes that are relevant to bladder contractility. The effects of retigabine and ML213 were attenuated by pre-incubation with 10µM XE991 (Kv7.1-7.5 channel blocker) (P