Summary
In the present study the tight junctions at the macula densa were compared to those of the adjacent straight and convoluted segments of the distal tubule using freeze fracturing and thin sectioning techniques. Only insignificant differences were found in the number of strands and the apico-basal depth of the tight junctions in the three distal tubular segments of rat, dog and tree shrew. In experiments with horseradish peroxidase on mice and tree shrews, the tracer did not penetrate the apical junctions in any of the distal tubular segments. Our findings do not support the concept of considerably higher permeability of the tight junctions at the macula densa, as previously reported. Gap junctions were never observed in the distal nephron. The present results suggest that the glomerulo-tubular feedback is more likely to be mediated by transcellular resorption of solutes than by passive diffusion through a leaky paracellular shunt pathway.
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Boll, H.-U., Forssmann, W.G., Taugner, R.: Studies on the juxtaglomerular apparatus. IV. Freezefracturing of membrane surfaces. Cell Tissue Res. 161, 459–469 (1975)
Boulpaep, E.L., Seely, J.F.: Electrophysiology of proximal and distal tubules in the autoperfused dog kidney. Am. J. Physiol. 221, 1084–1096 (1971)
Burg, M.B., Green, N.: Function of the thick ascending limb of Henle's loop. Am. J. Physiol. 224, 659–668 (1973)
Forssmann, M.G., Taugner, R.: Studies on the juxtaglomerular apparatus. V. The juxtaglomerular apparatus in Tupaia with special reference to intercellular contacts. Cell Tissue Res. 177, 291–305 (1977)
Giacomelli, F., Wiener, J.: Specialized junctions in the distal convoluted tubule of rat kidney. Anat. Rec. 185, 197–208 (1976)
Graham, R.C., Jr., Karnovsky, M.J.: The early stages of absorption of injected horse-radish peroxidase in the proximal tubules of the mouse kidney: Ultrastructural cytochemistry by a new technique. J. Histochem. Cytochem. 14, 291–302 (1966)
Malnic, G., Giebisch, G.: Some electrical properties of distal tubular epithelium in the rat. Am. J. Physiol. 223, 797–808 (1972)
Roesinger, B., Schiller, A., Taugner, R.: A freeze-fracture study of tight junctions in the pars convoluta and pars recta of the renal proximal tubule. Cell Tissue Res. 186, 121–133 (1978)
Schiller, A., Taugner, R., Roesinger, B.: Vergleichende Morphologie der Zonulae occludentes am Nierentubulus. Verh. Anat. Ges. 72, 229–234 (1978)
Schnermann, J.: The mechanism of the functional coupling between macula densa cells and glomerular arterioles. Proc. Int. Union Physiol. Sciences, XII, 283, No. 354 (1977). XXVIIth Int. Congr. Physiol. Sciences, July 18–23, 1977 (Paris)
Schnermann, J., Wright, F.S., Davis, J.M., Stackelberg, W. v., Grill, G.: Regulation of superficial nephron filtration rate by tubulo-glomerular feedback. Pflügers Arch. 318, 147 (1970)
Taugner, R., Schiller, A., Kaissling, B., Kriz, W.: Gap junction coupling between the JGA and the glomerular tuft. Cell Tissue Res. 186, 279–285 (1978)
Thurau, K., Mason, J.: The intrarenal function of the juxtaglomerular apparatus. In: MTP-Int. Review of Science, Physiology, Series one, Vol. 6 (K. Thurau, ed.), pp. 357–390. London: Butterworths 1974
Thurau, K., Schnermann, J.: Die Natriumkonzentration an den Macula densa Zellen als regulierender Faktor für das Glomerulumfiltrat. Klin. Wochenschr. 43, 410 (1965)
Wright, F.S., Briggs, J.P.: Feedback regulation of glomerular filtration rate. Am. J. Physiol. 233, F1-F7 (1977)
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These studies were supported by the German Research Foundation within the SFB 90 “Cardiovasculäres System”
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Schiller, A., Taugner, R. Are there specialized junctions in the pars maculata of the distal tubule?. Cell Tissue Res. 200, 337–344 (1979). https://doi.org/10.1007/BF00234846
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DOI: https://doi.org/10.1007/BF00234846