Activation of H(+)-K(+)-ATPase by CO(2) requires a basolateral Ba(2+)-sensitive pathway during K restriction.
Activation of H(+)-K(+)-ATPase by CO(2) requires a basolateral Ba(2+)-sensitive pathway during K restriction.
复制标题
CO(2) 激活 H( )-K( )-ATP 酶在 K 限制期间需要基底外侧 Ba(2 ) 敏感途径。
DOI：
10.1152/ajprenal.2000.279.1.f153
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Wingo,CS
中科院分区：
文献类型：
--
作者：
Zhou,X;Lynch,IJ;Xia,SL;Wingo,CS
本文研究了CO_2对钾限制动物肾皮质集合管（CCD）H ~+-K ~+-ATP酶的激活作用。将微灌注CCD暴露于10%CO2使净总CO2通量（JtCO 2）从4.9 ± 2.1增加到14.7 ± 4 pmol · mm-1· min-1（P< 0.05），并且这种作用被腔内应用H+-K+-ATP酶抑制剂Sch-28080阻断。在K通道阻断剂Luminal Ba存在下，暴露于CO2仍能使JtCO 2从6.0 ± 1.0增加到16.8 ± 2.8pmol· mm-1· min-1（P< 0.01），但在肾小管周围应用Ba可抑制这种刺激作用。CO2使K示踪标记物86 Rb流出量从93.1 ± 23.8nm/s增加到249 ± 60.2nm/s（P< 0.05）。这些结果表明：1）CO2暴露后H ~+-K ~+-ATP酶介导的酸化作用增强依赖于基底外侧Ba敏感性机制，这与正常钾饮食家兔的反应不同，在正常钾饮食家兔中，CO2暴露后H ~+-K ~+-ATP酶的激活依赖于顶端Ba敏感性途径;（2）K/Rb的吸收通过H ~+-K ~+-ATP酶途径，并通过基底外侧Ba敏感性通路。总之，这些数据是一致的假设之间的合作H+-K+-ATP酶介导的酸化和K退出途径的CCD调节K稳态。
We studied the activation of H+-K+-ATPase by CO2in the renal cortical collecting duct (CCD) of K-restricted animals. Exposure of microperfused CCD to 10% CO2increased net total CO2flux (Jt CO2) from 4.9 ± 2.1 to 14.7 ± 4 pmol · mm−1· min−1(P< 0.05), and this effect was blocked by luminal application of the H+-K+-ATPase inhibitor Sch-28080. In the presence of luminal Ba, a K channel blocker, exposure to CO2still stimulatedJt CO2from 6.0 ± 1.0 to 16.8 ± 2.8 pmol · mm−1· min−1(P< 0.01), but peritubular application of Ba inhibited the stimulation. CO2substantially increased86Rb efflux (a K tracer marker) from 93.1 ± 23.8 to 249 ± 60.2 nm/s (P< 0.05). These observations suggest that during K restriction1) the enhanced H+-K+-ATPase-mediated acidification after exposure to CO2is dependent on a basolateral Ba-sensitive mechanism, which is different from the response of rabbits fed a normal-K diet, where activation of the H+-K+-ATPase by exposure to CO2is dependent on an apical Ba-sensitive pathway; and2) K/Rb absorption via the apical H+-K+-ATPase exits through a basolateral Ba-sensitive pathway. Together, these data are consistent with the hypothesis of cooperation between H+-K+-ATPase-mediated acidification and K exit pathways in the CCD that regulate K homeostasis.