Barajas L, Powers K
Department of Pathology, Harbor-UCLA Medical Center, Torrance 90509.
Am J Anat. 1989 Dec;186(4):378-88. doi: 10.1002/aja.1001860407.
Experimental data suggest the proximal tubule as a major site of neurogenic influence on tubular function. The functional and anatomical axial heterogeneity of the proximal tubule prompted this study of the distribution of innervation sites along the early, mid, and late proximal convoluted tubule (PCT) of the rat. Serial section autoradiograms, with tritiated norepinephrine serving as a marker for monoaminergic nerves, were used in this study. Freehand clay models and graphic reconstructions of proximal tubules permitted a rough estimation of the location of the innervation sites along the PCT. In the subcapsular nephrons, the early PCT (first third) was devoid of innervation sites with most of the innervation occurring in the mid (middle third) and in the late (last third) PCT. Innervation sites were found in the early PCT in nephrons located deeper in the cortex. In juxtamedullary nephrons, innervation sites could be observed on the PCT as it left the glomerulus. This gradient of PCT innervation can be explained by the different tubulovascular relationships of nephrons at different levels of the cortex. The absence of innervation sites in the early PCT of subcapsular nephrons suggests that any influence of the renal nerves on the early PCT might be due to an effect of neurotransmitter released from renal nerves reaching the early PCT via the interstitium and/or capillaries.
实验数据表明近端小管是神经源性影响肾小管功能的主要部位。近端小管在功能和解剖学上的轴向异质性促使了本研究对大鼠近端曲管（PCT）早期、中期和晚期神经支配部位分布的探究。本研究采用了以氚标记去甲肾上腺素作为单胺能神经标志物的连续切片放射自显影片。近端小管的徒手黏土模型和图形重建使得对沿PCT神经支配部位的位置进行粗略估计成为可能。在被膜下肾单位中，PCT早期（前三分之一）没有神经支配部位，大部分神经支配发生在PCT中期（中间三分之一）和晚期（后三分之一）。在皮质中位置更深的肾单位的PCT早期发现了神经支配部位。在近髓肾单位中，当PCT离开肾小球时，可观察到神经支配部位。PCT神经支配的这种梯度可以通过皮质不同水平肾单位的不同肾小管-血管关系来解释。被膜下肾单位PCT早期缺乏神经支配部位表明，肾神经对PCT早期的任何影响可能是由于肾神经释放的神经递质通过间质和/或毛细血管到达PCT早期的作用。
