Briggs J P, Schnermann J
Annu Rev Physiol. 1987;49:251-73. doi: 10.1146/annurev.ph.49.030187.001343.
Tubuloglomerular feedback is an intrarenal control mechanism designed to regulate the amount of salt entering the distal nephron. Its regulatory efficiency depends upon the magnitude of the vascular response to changes in the luminal signal (the feedback relationship) and on the adjustments in proximal absorption, which determine the macula densa signal (the feedforward relationship). Studies of the feedback relationship have established that the vascular response is related to macula densa solute concentration in a sigmoidal fashion, with the normal operating point located somewhere in the steep portion of the curve. Thus, tubuloglomerular feedback tonically suppresses glomerular filtration rate, an effect that may be even more pronounced in juxtamedullary nephrons. An alteration in the feedforward function and thus in the macula densa signal is likely to participate in the vascular resistance changes initiated by changes in arterial pressure, elevated protein intake, or ADH administration. Our understanding of the intra- and intercellular mechanisms underlying information transfer across the JGA is currently incomplete, but there is some information about the biochemical characteristics of the cellular components. The enzymatic and surface properties establish the distinct nature of the macula densa cells and indicate a distinct function.
球管反馈是一种肾内控制机制，旨在调节进入远端肾单位的盐量。其调节效率取决于血管对管腔信号变化的反应强度（反馈关系）以及近端重吸收的调节，近端重吸收决定了致密斑信号（前馈关系）。对反馈关系的研究表明，血管反应与致密斑溶质浓度呈S形相关，正常工作点位于曲线的陡峭部分。因此，球管反馈持续抑制肾小球滤过率，这种作用在近髓肾单位可能更为明显。前馈功能的改变以及致密斑信号的改变可能参与了由动脉压变化、蛋白质摄入量增加或给予抗利尿激素引起的血管阻力变化。我们目前对跨球旁器信息传递的细胞内和细胞间机制的理解尚不完整，但已有一些关于细胞成分生化特性的信息。酶学和表面特性确定了致密斑细胞的独特性质，并表明其具有独特功能。
