Differential expression of T- and L-type voltage-dependent calcium channels in renal resistance vessels
Differential expression of T- and L-type voltage-dependent calcium channels in renal resistance vessels
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DOI：
10.1161/hh1901.097126
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发表时间：
2001-09-28
影响因子：
20.1
通讯作者：
Skott, O
中科院分区：
文献类型：
--
作者：
Hansen, PB;Jensen, BL;Skott, O
在分子水平和功能水平上测定了电压依赖性钙通道在肾小球前和肾小球后阻力血管中的分布。逆转录-聚合酶链反应分析的显微切割大鼠肾小球前血管和培养的平滑肌细胞显示共同表达的mRNA的T型亚基（Ca（v）3.1，Ca（v）3.2）和L型亚基（Ca（v）1.2）。在延髓输出小动脉和外髓直血管中也观察到相同的表达模式。皮质传出小动脉未检测到钙通道信息。Ca（v）1.2蛋白在大鼠肾小球前血管、延髓输出小动脉和直小血管的免疫组化染色中可见。皮质传出小动脉免疫阳性。用数字荧光成像显微镜记录的细胞内钙浓度显示，在分离的传入小动脉（140 +/- 25%）和延髓传出小动脉（118 +/- 21%）中，响应于K+（100 mmol/L）的钙显著增加。这些钙反应减弱的L-型拮抗剂calciseptine和T-型拮抗剂米贝拉地尔。在皮质传出小动脉中，细胞内钙对K+的反应增加（21 +/- 9%）。米贝拉地尔和镍浓度依赖性地阻断K+引起的兔传入小动脉收缩。Calciseptine阻断K+介导的收缩（EC_（50））为8 × 10 ~（-14））。S-（-）-Bay K 8644对传入小动脉的血管直径没有影响。我们的结论是，电压依赖性L-和T-型钙通道的表达和功能的重要性，在肾皮质肾小球前血管，在aptamedullary传出小动脉，并在外髓直血管，但不是在皮质传出小动脉。
The distribution of voltage-dependent calcium channels in kidney pre- and postglomerular resistance vessels was determined at the molecular and functional levels. Reverse transcription-polymerase chain reaction analysis of microdissected rat preglomerular vessels and cultured smooth muscle cells showed coexpression of mRNAs for T-type subunits (Ca(v)3.1, Ca(v)3.2) and for an L-type subunit (Ca(v)1.2). The same expression pattern was observed in juxtamedullary efferent arterioles and outer medullary vasa recta. No calcium channel messages were detected in cortical efferent arterioles. Ca(v)1.2 protein was demonstrated by immunochemical labeling or rat preglomerular vasculature and juxtamedullary efferent arterioles and vasa recta. Cortical efferent arterioles were not immunopositive. Recordings of intracellular calcium concentration with digital fluorescence imaging microscopy showed a significant increase of calcium in response to K+ (100 mmol/L) in isolated afferent arterioles (140 +/- 25%) and in juxtamedullary efferent arterioles (118 +/- 21%). These calcium responses were attenuated by the L-type antagonist calciseptine and by the T-type antagonist mibefradil. Intracellular calcium increased in response to K+ in cortical efferent arterioles (21 +/- 9%). Mibefradil and nickel concentration dependently blocked K+-induced contraction of perfused rabbit afferent arterioles. Calciseptine blocked the contraction mediated by K+ (EC50 8 X 10(-14)). S-(-)-Bay K 8644 had no effect on vascular diameter in the afferent arteriole. We conclude that voltage-dependent L- and T-type calcium channels are expressed and of functional significance in renal cortical preglomerular vessels, in juxtamedullary efferent arterioles, and in outer medullary vasa recta, but not in cortical efferent arterioles.