Characterization of human urinary bladder K_ATP channels containing SUR2B splice variants expressed in L-cells

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• 作者：Scott ; Victoria E. ; Davis-Taber ; Rachel A. ; Silvia ; Christopher ; Hoogenboom ; Lisa ; Choi ; Won ; et. al.
• 关键词：K_ATP channel ; SUR2B ; Cell line ; stable ; Urinary bladder ; [¹²⁵I]-A-312110 ; K⁺ channel opener
• 刊名：European Journal of Pharmacology
• 出版年：2004
• 期刊代码：24_00142999
• 类别：neu
• 出版时间：January 12, 2004
• 卷：483
• 期：2-3
• 页码：195-205
• 文件大小：496 K

摘要

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 (DiBAC₄(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.