首页> 外文期刊>American Journal of Physiology >Effects of isoprostane on tubuloglomerular feedback: roles of TP receptors, NOS, and salt intake.
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Effects of isoprostane on tubuloglomerular feedback: roles of TP receptors, NOS, and salt intake.

机译:异前列腺素对肾小球肾小管反馈的影响:TP受体,NOS和盐摄入量的作用。

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摘要

A thromboxane prostanoid receptor (TP-R) agonist U-46,619 enhances tubuloglomerular feedback (TGF). Glomerular expression of TP-R and enhancement of TGF by U-46,619 increase with salt intake. We investigated the hypothesis that 8-isoprostaglandin F(2alpha) (8-Iso) activates TGF via TP-R. The maximal TGF response in rats was assessed from the fall in proximal stop flow pressure (PSF; an index of glomerular capillary pressure) during loop of Henle (LH) microperfusion of artificial tubular fluid (ATF) at 40 nl/min. Microperfusion of 8-Iso (10(-4) M) into the efferent arteriole (EA) enhanced TGF responses by 20 +/- 3% (P < 0.01). TGF response to 8-Iso was independent of dietary salt [DeltaTGF%, low salt (LS): 21 +/- 5%; normal salt (NS): 17 +/- 4%; high salt (HS): 29 +/- 8%, not significant (ns)], unlike the salt-dependent effect of U-46,619 (DeltaTGF%, LS: 41 +/- 5%; NS: 52 +/- 4%; HS: 112 +/- 21%). Ifetroban, the TP-R antagonist, abolished TGF responses to 8-Iso and U-46,619 at all levels of salt intake.During luminal perfusion of N-monomethyl-l-arginine (l-NMA), the effect of 8-Iso on TGF was enhanced in NS and HS but not in LS (LS: 22 +/- 6 vs. LS + l-NMA: 28 +/- 6%, ns; NS: 18 +/- 4 vs. NS + l-NMA: 40 +/- 4, P < 0.01; HS: 27 +/- 3 vs. HS + l-NMA: 65 +/- 6, P < 0.01). However, U-46,619 did not further increase TGF after l-NMA in all salt groups (LS: 43 +/- 7 vs. LS + l-NMA: 51 +/- 6, ns; NS: 52 +/- 7 vs. NS + l-NMA: 48 +/- 8, ns; HS: 114 +/- 21 vs. HS + l-NMA: 74 +/- 22, ns). In conclusion, activation of TP receptors by U-46,619 and 8-Iso-PGF(2alpha) enhances TGF. In addition, the effect of U-46,619 was salt dependent, whereas the effect of 8-Iso-PGF(2alpha) was salt independent. However, stimulation of NO by 8-isoprostanes masks its salt-sensitive effect on TGF.
机译:血栓烷类前列腺素受体(TP-R)激动剂U-46,619可增强肾小管肾小球反馈(TGF)。 TP-R的肾小球表达和U-46,619对TGF的增强随盐摄入的增加而增加。我们调查了8-isoprostaglandin F(2alpha)(8-Iso)通过TP-R激活TGF的假设。大鼠的最大TGF反应是通过以40 nl / min的人造管液(ATF)进行的Henle(LH)微灌流回路中的近端停止血流压力(PSF;肾小球毛细血管压力指数)的下降来评估的。将8-Iso(10(-4)M)微灌注到传出的小动脉(EA)中,可使TGF反应提高20 +/- 3%(P <0.01)。 TGF对8-Iso的反应与饮食盐无关[DeltaTGF%,低盐(LS):21 +/- 5%;普通盐(NS):17 +/- 4%;高盐(HS):29 +/- 8%,不显着(ns)],与U-46,619的盐依赖性效应不同(DeltaTGF%,LS:41 +/- 5%; NS:52 +/- 4 %; HS:112 +/- 21%)。 TP-R拮抗剂Ifetroban取消了在所有盐摄入水平下对8-Iso和U-46,619的TGF反应。在腔内灌注N-单甲基-1-精氨酸(1-NMA)期间,8-Iso对TGF在NS和HS中增强,但在LS中则没有增强(LS:22 +/- 6 vs. LS + 1-NMA:28 +/- 6%,ns; NS:18 +/- 4 vs.NS + 1-NMA :40 +/- 4,P <0.01; HS:27 +/- 3,相对于HS + 1-NMA:65 +/- 6,P <0.01)。但是,U-46,619在所有盐组中的l-NMA后并未进一步提高TGF(LS:43 +/- 7 vs. LS + l-NMA:51 +/- 6 ns; NS:52 +/- 7 vs NS + 1-NMA:48 +/- 8,ns; HS:114 +/- 21对HS + 1-NMA:74 +/- 22,ns)。总之,U-46,619和8-Iso-PGF(2alpha)激活TP受体可增强TGF。此外,U-46,619的作用与盐有关,而8-Iso-PGF(2alpha)的作用与盐无关。然而,通过8-异前列腺素对NO的刺激掩盖了其对TGF的盐敏感性作用。

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