title: Characterization of human urinary bladder KATP channels containing SUR2B splice variants expressed in L-cells.
abstract: The molecular properties of the sulfonylurea receptor 2 (SUR2) subunits of K(ATP) channels expressed in urinary bladder were assessed by polymerase chain reaction (PCR). This showed that SUR2B exon 17- mRNA (72%) was predominant over the SUR2B exon 17+ splice variant (28%). The pharmacological properties of both of these isoforms stably expressed in mouse Ltk(-)cells (L-cells) with K(IR) 6.2 were determined by measuring changes in membrane potential responses evoked by K(+) channel openers using bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC(4)(3)) fluorescence. The rank order potency of a variety of structurally distinct K(+) channel openers was found to be the same in both stable cell lines and compared well with guinea pig bladder cells. The potency of these compounds in the SUR2B exon 17- cells more closely resembled the potency measured in guinea pig bladder unlike the cell line containing the SUR2B exon 17+ subtype. Analysis of the displacement of [125I]A-312110 binding with the same K(+) channel openers to the SUR2B exon 17- cells showed excellent correlation to those measured in guinea pig bladder. This study supports the notion that K(ATP) channels containing SUR2B exon 17- represent a major splice variant expressed in urinary bladder smooth muscle.
authors.affiliation: Neuroscience Disease Research AP9A, Rm. 218, Abbott Laboratories, 100 Abbott Park Rd.,Abbott Park, IL 60064-6125, USA. victoria.e.scott@abbott.com
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Scott
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Davis-Taber
authors.forename: Christopher
authors.initials: C
authors.lastname: Silvia
authors.forename: Lisa
authors.initials: L
authors.lastname: Hoogenboom
authors.forename: Won
authors.initials: W
authors.lastname: Choi
authors.forename: Paul
authors.initials: P
authors.lastname: Kroeger
authors.forename: Kristi L
authors.initials: KL
authors.lastname: Whiteaker
authors.forename: Murali
authors.initials: M
authors.lastname: Gopalakrishnan
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000255:Adenosine Triphosphate / Q000235:genetics / Q000502:physiology; D000577:Amides / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001577:Benzophenones / Q000378:metabolism / Q000494:pharmacology; D004274:DNA, Recombinant / Q000096:biosynthesis / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005091:Exons / Q000187:drug effects / Q000502:physiology; D006168:Guinea Pigs; D006801:Humans; D007739:L Cells; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics; D051379:Mice; D015221:Potassium Channels / Q000235:genetics*; D024661:Potassium Channels, Inwardly Rectifying / Q000737:chemistry* / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D011955:Receptors, Drug / Q000235:genetics*; D064233:Sulfonylurea Receptors; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism*
chemical_list: C577510:ABCC9 protein, human; D018528:ATP-Binding Cassette Transporters; C577511:Abcc9 protein, mouse; D000577:Amides; D001577:Benzophenones; D004274:DNA, Recombinant; D008565:Membrane Proteins; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors; C095007:Zeneca ZD 6169; C117780:mitochondrial K(ATP) channel; D000255:Adenosine Triphosphate