title: NS19504: a novel BK channel activator with relaxing effect on bladder smooth muscle spontaneous phasic contractions.
abstract: Large-conductance Ca(2+)-activated K(+) channels (BK, KCa1.1, MaxiK) are important regulators of urinary bladder function and may be an attractive therapeutic target in bladder disorders. In this study, we established a high-throughput fluorometric imaging plate reader-based screening assay for BK channel activators and identified a small-molecule positive modulator, NS19504 (5-[(4-bromophenyl)methyl]-1,3-thiazol-2-amine), which activated the BK channel with an EC50 value of 11.0 ± 1.4 µM. Hit validation was performed using high-throughput electrophysiology (QPatch), and further characterization was achieved in manual whole-cell and inside-out patch-clamp studies in human embryonic kidney 293 cells expressing hBK channels: NS19504 caused distinct activation from a concentration of 0.3 and 10 µM NS19504 left-shifted the voltage activation curve by 60 mV. Furthermore, whole-cell recording showed that NS19504 activated BK channels in native smooth muscle cells from guinea pig urinary bladder. In guinea pig urinary bladder strips, NS19504 (1 µM) reduced spontaneous phasic contractions, an effect that was significantly inhibited by the specific BK channel blocker iberiotoxin. In contrast, NS19504 (1 µM) only modestly inhibited nerve-evoked contractions and had no effect on contractions induced by a high K(+) concentration consistent with a K(+) channel-mediated action. Collectively, these results show that NS19504 is a positive modulator of BK channels and provide support for the role of BK channels in urinary bladder function. The pharmacologic profile of NS19504 indicates that this compound may have the potential to reduce nonvoiding contractions associated with spontaneous bladder overactivity while having a minimal effect on normal voiding.
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Bernhard
authors.initials: B
authors.lastname: Nausch
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Frederik
authors.initials: F
authors.lastname: Rode
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Susanne
authors.initials: S
authors.lastname: Jørgensen
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Antonio
authors.initials: A
authors.lastname: Nardi
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Mads P G
authors.initials: MP
authors.lastname: Korsgaard
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Charlotte
authors.initials: C
authors.lastname: Hougaard
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Adrian D
authors.initials: AD
authors.lastname: Bonev
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: William D
authors.initials: WD
authors.lastname: Brown
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Tino
authors.initials: T
authors.lastname: Dyhring
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Dorte
authors.initials: D
authors.lastname: Strøbæk
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Søren-Peter
authors.initials: SP
authors.lastname: Olesen
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Palle
authors.initials: P
authors.lastname: Christophersen
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Morten
authors.initials: M
authors.lastname: Grunnet
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.).
authors.forename: Mark T
authors.initials: MT
authors.lastname: Nelson
authors.affiliation: NeuroSearch A/S, Ballerup, Denmark (F.R., S.J., A.N., M.P.G.K., C.H., W.D.B., T.D., D.S., S.-P.O., P.C., M.G., L.C.B.R.); University of Vermont, Department of Pharmacology, Burlington, Vermont (B.N., A.D.B., M.T.N.); and Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (M.T.N.) lcbr@lundbeck.com.
authors.forename: Lars C B
authors.initials: LC
authors.lastname: Rønn
mesh_terms: D000818:Animals; D002120:Calcium Channel Agonists / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D057809:HEK293 Cells; D006801:Humans; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000819:agonists* / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects* / Q000502:physiology; D009924:Organ Culture Techniques; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology
chemical_list: D002120:Calcium Channel Agonists; D051036:Large-Conductance Calcium-Activated Potassium Channels