KUL-7211

KUL 7211 is a selective β-adrenoceptor agonist. IC50 & Target:β-adrenoceptor^[1] In Vitro: KUL 7211 (KUL-7211) is a new β-adrenoceptor agonist in vitro. In rat isolated organs, its selectivities, for inhibition of spontaneous uterine contraction (mediated via β₂-adrenergic stimulation) and inhibition of colonic contraction (via β₃-adrenergic stimulation) versus increase in atrial rate (via β₁-adrenergic stimulation), are 56.3 and 242.2, respectively. KUL 7211 relaxes 80 mM KCl induced tonic contractions in both rabbit (pD₂ value: 5.86±0.13, whose ureteral relaxation is mediated via β₂-adrenergic stimulation) and canine (pD₂ value: 6.52±0.16, via β₃-adrenergic stimulation) isolated ureters in a concentration-dependent manner. These KUL 7211-induced relaxing effects are antagonized by ICI-118,551 (selective β₂-adrenoceptor antagonist, pK_B value: 8.91±0.24) in the rabbit ureter and by bupranolol (non-selective β-adernoceptor antagonist, pK_B value: 6.85±0.12) in the canine ureter. KUL 7211 also reduces the spontaneous rhythmic contraction in a canine ureteral spiral preparation in a concentration-dependent manner, the pD₂ value being 6.83±0.20. These data clearly demonstrate that KUL 7211 selectively stimulates both ureteral β₂- and β₃-adrenoceptors and potently relaxes ureteral smooth muscle^[1].