A new ATP-sensitive potassium channel opener reduces blood pressure and reverses cardiovascular remodeling in experimental hypertension

Some potassium channel openers (KCOs) are potent vasodilators that mainly target the ATP-sensitive potassium channels in vascular smooth muscle cells. Their lack of tissue selectivity limits their clinical use in hypertension therapy. Iptakalim [2,3-dimethyl-n-(1-methylethyl)-2-butylamine], which belongs to a novel chemical type of KCO, possesses unique pharmacological characteristics. In vitro experiments have shown that iptakalim could limit its vasorelaxing actions to resistance vessels. In this study, we investigate the antihypertensive effects of iptakalim on two different experimental hypertensive models: stroke-prone, spontaneously hypertensive rats (SHRsps) and two-kidney with one-clip renal hypertensive dogs (2K1C RHD). In acute hypotensive tests, iptakalim showed stable, long-lasting antihypertensive effects in SHRsps and 2K1C RHDs. Mean-while, it had little effect on heart rate when compared with pinacidil, nifedipine, captopril, or bisoprolol. In experimental therapeutic tests, repeated doses in SHRsps for 30 days or in 2K1C RHDs for 14 days produced consistent antihypertensive effects without causing tolerance. In separate experiments, chronic administration of iptakalim resulted in reversing hypertensive vascular remodeling in spontaneously hypertensive rats and hypertensive cardiac remodeling in SHRsps. These results suggest that iptakalim is a promising antihypertensive drug.