Tubuloglomerular feedback dependence of autoregulation in rat juxtamedullary afferent arterioles.
Tubuloglomerular feedback dependence of autoregulation in rat juxtamedullary afferent arterioles.
复制标题
大鼠近髓传入小动脉自动调节的肾小球反馈依赖性。
DOI：
10.1038/ki.1990.129
复制
发表时间：
1990
影响因子：
19.6
通讯作者：
Casellas,D
中科院分区：
文献类型：
--
作者：
Moore,LC;Casellas,D
大鼠近髓传入小动脉自动调节的肾小球反馈依赖性。在体外血液灌注的近髓肾单位中进行实验，以评估中晚期（mAA）和近肾小球（jAA）传入小动脉的自动调节血管收缩的肾小球反馈（TGF）依赖性。通过将 0.1 mM 呋塞米溶液直接微量输注到致密斑 (MD) 段，对 TGF 机制进行急性抑制之前和之后，对浅表血管管腔直径的灌注压 (PP) 依赖性变化进行视频测量。当七个容器中的 PP 从 60 升至 123 ± 7 mm Hg 时，jAA 直径减小了 29 ± 3%（SEM，N = 7）。在速尿输注过程中，PP 发生相同的变化，jAA 直径仅下降 7 ± 2%。用 1 微摩尔尼莫地平阻断钙通道后，jAA 管腔直径增加 21 ± 7%。在 8 个 jAA 中观察到类似的反应模式，其中 TGF 在 MD 处被油块抑制。 mAA 的自动调节反应也因 TGF 抑制而减弱。将 PP 从 60 毫米汞柱提高到 120 毫米汞柱会导致 TGF 抑制前后 mAA 管腔直径分别减少 15 ± 2% 和 7 ± 2%。这些结果表明，肾小球中部和肾小球旁传入小动脉段的自动调节反应是由 TGF 和不依赖 TGF 的生肌机制介导的。
Tubuloglomerular feedback dependence of autoregulation in rat juxta-medullary afferent arterioles. Experiments were performed in blood-perfused juxtamedullary nephrons in vitro to evaluate the tubuloglomerular feedback (TGF) dependence of autoregulatory vasoconstriction in mid-to-late (mAA) and juxtaglomerular (jAA) afferent arterioles. Video-metric measurements were made of perfusion pressure (PP) dependent changes in lumen diameter of superficial vessels before and after acute inhibition of the TGF mechanism by direct microinfusion of 0.1 mM furosemide solution into the macula densa (MD) segment. When PP was raised from 60 to 123 ± 7 mm Hg in seven vessels, jAA diameter decreased by 29 ± 3% (SEM, N = 7). During furosemide infusion with the same change in PP, jAA diameter decreased only 7 ± 2%. After calcium channel blockade with 1 micromolar nimodipine, jAA lumen diameter increased by 21 ± 7%. A similar pattern of responses was observed in eight jAA where TGF was inhibited with an oil block at the MD. mAA autoregulatory responses were also blunted by TGF inhibition. Raising PP from 60 to 120 mm Hg resulted in 15 ± 2% and 7 ± 2% decreases in mAA luminal diameter before and after TGF inhibition. These results demonstrate that the autoregulatory responses in mid- and juxtaglomerular afferent arteriolar segments are mediated by both TGF and a TGF-independent myogenic mechanism.