Li L, Wu J, Jiang C
Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30302-4010, USA.
J Membr Biol. 2003 Nov 1;196(1):61-9. doi: 10.1007/s00232-003-0625-z.
ATP-sensitive K(+) channels (K(ATP)) couple the intermediary metabolism to cellular excitability and play an important role in the cardio-protective effect of ischemic preconditioning and the activity-dependent autoregulation of cerebral circulation. Although previous studies using PCR and Northern blot suggest that the vascular isoform may consist of Kir6.1 and SUR2B, their expression and precise distribution in various vasculatures remain unknown. To illustrate their vascular expression, we performed this study using in situ hybridization histochemistry. Antisense riboprobes were synthesized by in vitro transcription and labeled with digoxigenin. Distributions of these mRNAs in the various blood vessels were revealed under a bright-field microscope. The expression of Kir6.1 and SUR2B mRNAs was observed in small and intermediate arteries as well as arterioles in several tissues, including basilar, vertebral, mesenteric, coronary and renal arteries. The transcripts were found in arterial smooth muscles. Also, we observed Kir6.1/SUR2B expression in capillary beds. The Kir6.1 and SUR2B expression pattern showed clear overlap, suggesting that they may form heteromeric K(ATP) channels in these tissues. The Kir6.1 and SUR2B stains were detected in aorta and renal tubular cells although their expression level was extremely low. In contrast, the Kir6.1 and SUR2B mRNAs were not seen in vena cava, other small veins, myocardium and skeletal muscles. With their strong expression in small arteries and capillaries, it is very likely that the Kir6.1 and SUR2B form the vascular isoform of K(ATP) channels in these vasculatures.
ATP敏感性钾通道（K(ATP)）将中间代谢与细胞兴奋性联系起来，在缺血预处理的心脏保护作用以及脑循环的活动依赖性自身调节中发挥重要作用。尽管先前使用PCR和Northern印迹的研究表明血管亚型可能由Kir6.1和SUR2B组成，但它们在各种血管中的表达和精确分布仍然未知。为了阐明它们在血管中的表达，我们使用原位杂交组织化学进行了这项研究。反义核糖探针通过体外转录合成并用地高辛标记。在明场显微镜下揭示了这些mRNA在各种血管中的分布。在包括基底动脉、椎动脉、肠系膜动脉、冠状动脉和肾动脉在内的几个组织的小动脉、中等动脉以及小动脉中观察到了Kir6.1和SUR2B mRNA的表达。转录本在动脉平滑肌中被发现。此外，我们在毛细血管床中观察到了Kir6.1/SUR2B的表达。Kir6.1和SUR2B的表达模式显示出明显的重叠，表明它们可能在这些组织中形成异源K(ATP)通道。在主动脉和肾小管细胞中检测到了Kir6.1和SUR2B染色，尽管它们的表达水平极低。相比之下，在腔静脉、其他小静脉、心肌和骨骼肌中未见到Kir6.1和SUR2B mRNA。由于它们在小动脉和毛细血管中强烈表达，Kir6.1和SUR2B很可能在这些血管中形成K(ATP)通道的血管亚型。
