Renal blood vascular system in the elasmobranch, Raja erinacea mitchill, in relation to kidney zones

Abstract

The arrangement and structure of renal blood vessels were studied in a marine skate with injection of silicone rubber and methacrylate resin after intravenous administration of epinephrine and perfusion fixation. The methacrylate casts were investigated with the scanning electron microscope. Histology was performed by light and transmission electron microscopy of serial sections. The course of the blood vessels is described in relation to the renal zones of lateral bundles and mesial tissue. Each nephron performs two loops in the lateral bundles and two coilings in the mesial tissue before it joins the collecting duct system. The lateral bundles contain an elaborate countercurrent arrangement of neck segment, proximal tubule segment PIa, early distal tubule segment, and collecting tubule. Within the bundles, the nephron portions are associated with a blind-ended central vessel, which is connected with the venous sinuses of the mesial tissue. The microcirculatory bed around the bundles is supplied with arterial blood via small bundle arteries that originate from the intrarenal arteries in parallel to the afferent arterioles of the glomeruli. The efferent arterioles of the glomeruli convey their blood to the peritubular sinuses of the mesial tissue, which is largely irrigated with venous blood of the renal portal system. The mesial tissue, containing the proximal tubule segments PIb and PII, intermediate segment, and late distal tubule segment LDTb, receives venous blood from the caudal vein and the lateral musculature via afferent renal and intrarenal veins and from the efferent arterioles of the glomeruli and venules of the microcirculation of the bundles. The sinuses are drained by efferent renal veins via efferent intrarenal veins. By comparing the renal structures of the skate with those of dogfish, a unique type of circulation--as related to nephron segments, renal zones, and fine structure of the wall of the vessels--is revealed in marine elasmobranchs of different evolutionary levels.

Renal tubule of dogfish, Scyliorhinus caniculus: A comprehensive study of structure with emphasis on intramembrane particles and immunoreactivity for H+‐K+‐adenosine triphosphatase

“…The electron microscopic examination of histological sections and freeze-fracture replicae revealed profound morphological differences between cells of two major portions of the proximal tubule, the proximal tubule segment PI and the proximal tubule segment PII. This confirms our previous studies Hentschel, 1982, 1983;Elger, 1982, 1987b;Hentschel, 1987Hentschel, , 1988Hentschel, , 1991.…”

“…Light and electron microscopic examination of tissue sections and vascular casts in conjunction with comparative zoological studies gave evidence for conspicuous differences between two major portions of the distal nephron in marine elasmobranchs Hentschel, 1982, 1983;Elger, 1982, 1987a;Hentschel, 1987Hentschel, , 1988Hentschel, , 1991. The present results from electron microscopy of thin sections and freeze-fracture replicaes corroborate and extend these previous observations.…”

“…The morphology of the elasmobranch kidney has been rather well documented by the examination of two representative species from different systematic groups, the Selachii (Scyliorhinus cuniculus) and the Batoidea (Ruju erinuceu), by light and electron microscopic study of histological sections and vascular casts Hentschel, 1982, 1983;Hentschel, 1987Hentschel, , 1988Hentschel, , 1991Elger, 1982, 1987a). In the present study the complicated system of loops and coilings of the nephron was visualized with computeraided 3D reconstruction.…”

Using zebrafish to study podocyte genesis during kidney development and regeneration

“…Further, zebrafish undergo nephron epithelial regeneration and de novo nephron formation, termed neonephrogenesis, after experiencing kidney damage Zhou et al, 2010). Numerous fish species, including goldfish, dogfish, skate, and medaka, likewise can regenerate damaged nephrons and undergo neonephrogenesis (Augusto et al, 1996;Elger et al, 2003;Hentschel, 1988;Reimschuessel, 2001;Reimschuessel and Williams, 1995;Reimschuessel et al, 1990;Salice et al, 2001;Watanabe et al, 2009). These capabilities are not present in higher vertebrates, whose response to acute kidney damage is limited to tubule epithelial regeneration, and upon chronic damage undergo scar formation that can lead to advancing nephron loss and ESRD (Li and Wingert, 2013).…”

Heterogenous distribution of glycoconjugates in the kidney of dogfish Scyliorhinus caniculus (l.) with reference to changes in the glycosylation pattern during ontogenetic development of the nephron

“…Originating from rather large renal corpuscles, the tubules take a regular course through the mesial tissue zone and elaborate countercurrent system in the renal zone of lateral bundles, alternating two times between the zones. The last mesial convolution of tubules, the late distal tubule, merges with the collecting tubule, and this tubular portion thereafter runs in close association with the two hairpin loops through the lateral bundles Hentschel, 1987Hentschel, , 1988Hentschel, , 1991Hentschel and Elger, 1982. These specializations in architecture and the development of specific renal structures, such as a central vessel, which accompanies the loops of the single nephron in the separating bundle sheath, are considered as morphological correlates to the peculiar renal function in these marine fish (for review of literature, see, e.g., Hentschel and Elger, 1987;Dantzler, 1988;Henderson et al, 1989).…”