The Kv7 voltage-gated potassium family comprises five KCNQ-encoded channels (Kv7.1-7.5). Our group have shown that Kv7 channels are present functionally in vascular and non-vascular smooth muscle cells (Yeung et al., 2007). Here, expression of Kv7.1, Kv7.4 and Kv7.5 appears to predominate in contrast to the neuronal expression profile (Kv7.2/7.3). Recently, activators of Kv7 channels have been developed that show considerable selectivity for Kv7.2-7.5. The aim of the present study was to compare the effect of 4 of these activators: the acrylamide S-1 (S-1), ICA-27243, BMS-204352 and retigabine, in a Langendorff heart and in vivo. According to the Danish guidelines for animal experiments, male Wistar rats (~250g) were anaesthetised with i.p. injection of 50 mg/ml mebumol-sodium. The heart was removed, mounted in a vertical Langendorff and perfused with increasing concentrations of the Kv7 activators after a baseline period of ~30 mins. We also tested these activators in vivo on male Wistar rats; here the activators were administered by gavage at 3, 10 and 30 mg/kg alongside a vehicle control. Changes in blood pressure and core temperature were measured using a DSI Pressure and ECG telemetry implant (TM11M2-C50-PXT; St. Paul, MN USA). Exposure of the Langendorff heart to increasing concentrations of the Kv7 activators revealed a concentration-dependent increase in coronary flow. Application of BMS-204352 and S-1 (1 µM) increased coronary flow by 33.9 ± 12.7 % and 28.1 ± 1.5 %, respectively. Subsequent application of the pan-Kv7 blocker linopirdine (10 µM) reversed the effects of all Kv7 activators tested. No significant changes were observed on heart rate or the ECG. Results from the in vivo experiments show that approximately 30 mins after drug administration, changes in blood pressure and core temperature were observed. The effects observed in vivo were also concentration dependent. This study is the first to fully test the effect of Kv7 activators in the heart where significant increases in the coronary flow were observed. This study also demonstrates the effects of the Kv7 activators on blood pressure and core temperature in vivo.