Braam B, Turkstra E, Koomans H A
Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands.
Acta Physiol Scand. 2000 Jan;168(1):125-32. doi: 10.1046/j.1365-201x.2000.00659.x.
It is now clear that nitric oxide (NO) exerts a substantial influence on renal function and that the kidney has a high capacity to produce NO. However, there are at least two different NO systems in the kidney. The interplay between NO generated by the endothelium and by the macula densa is considered in this review. It seems that endothelial NO increases in response to an increase in perfusion pressure and an increase in distal delivery, whereas macula densa NO decreases upon a sustained increase in distal delivery. Furthermore, evidence is accumulating that macula densa NO may well mediate renin release. Though seemingly in contrast, both the response of the endothelial NO and of the macula densa NO system seem appropriate to restore a perturbation of fluid balance. The function of the tubuloglomerular feedback (TGF) mechanism is likely to be influenced by both sources of NO, because of the close proximity of these NO producing cells to the vascular smooth muscle cells of the afferent arteriole. The endothelial NO system seems to be responsible for short-term, dampening actions to increased afferent arteriolar tone elicited by activation of the TGF system. The macula densa NO system, on the other hand, is probably adapting TGF responses to sustained increases in distal delivery. The analysis presented in this paper is an attempt to integrate the function of the two NO systems into physiological regulation. The exact role of the medullary NOS enzymes remains to be further elucidated.
现在已经清楚，一氧化氮（NO）对肾功能有重大影响，而且肾脏产生NO的能力很强。然而，肾脏中至少存在两种不同的NO系统。本文综述了内皮细胞产生的NO与致密斑产生的NO之间的相互作用。似乎内皮型NO会随着灌注压力的增加和远端输送量的增加而增加，而致密斑NO会在远端输送量持续增加时减少。此外，越来越多的证据表明，致密斑NO很可能介导肾素释放。虽然看似相反，但内皮型NO和致密斑NO系统的反应似乎都有助于恢复体液平衡的紊乱。由于这些产生NO的细胞与入球小动脉的血管平滑肌细胞距离很近，肾小管-肾小球反馈（TGF）机制的功能可能会受到这两种NO来源的影响。内皮型NO系统似乎负责对TGF系统激活引起的入球小动脉张力增加进行短期的抑制作用。另一方面，致密斑NO系统可能使TGF反应适应远端输送量的持续增加。本文的分析试图将这两种NO系统的功能整合到生理调节中。髓质NOS酶的确切作用仍有待进一步阐明。
