The Ultrastructure of the Renal Medulla and the Interstitial Cells

Bohman, Sven‐Olof

doi:10.1007/978-1-4684-8115-0_2

Cited by 31 publications

(36 citation statements)

References 57 publications

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“…Using confocal fluorescence microscopy and the pH-sensitive fluorescence marker 2'7'-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) to visualize RMICs in the intact non-fixed rat papilla, we have recently confirmed this ladder-like arrangement of RMICs between the loops of Henle and vasa recta (111 reticulum, free ribosomes, polysomes, and lysosomes, as well as numerous homogeneous osmiophilic lipid droplets (Fig. 2), which are readily stained with Oil red 0 (16, 110,112). For this reason they are often referred to as lipid-laden interstitial cells (6,7,110,112).…”

Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 54%

“…Moreover, a novel Ang IV receptor binding site, AT4, has recently been described in basolateral and brush border membranes of rabbit proximal tubules and human collecting duct cells (108,109), but the role of this novel Ang receptor binding site in the kidney is currently not understood. (110), or macrophages (6, 7), are distributed throughout the cortex and medulla. Type III interstitial cells, the pericytes, represent a transitional cell type of interstitial fibroblasts and vascular smooth muscle cells and also occur in the medulla, where these cells are embedded in the basal membranes associated with the descending vasa recta (6, 7, 110).…”

Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 99%

“…2). These cells have extensive cellular contacts, via their prominent cytoplasmic processes, with the basal membranes of the loop of Henle and vasa recta in vivo (110). Because of these unique structural relationships with renal tubules and medullary blood vessels, they have been described as appearing like "the rungs of a ladder" (Fig.…”

Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 99%

“…2), which are readily stained with Oil red 0 (16, 110,112). For this reason they are often referred to as lipid-laden interstitial cells (6,7,110,112). The number of lipid droplets in RMICs varies considerably from the inner stripe of the outer medulla to the papilla, where the most abundant lipid droplets are observed (5, 6, 110).…”

Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 99%

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Localization and Functional Properties of Angiotensin II AT1 Receptors in the Kidney. Focus on Renomedullary Interstitial Cells.

et al. 1997

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The renal medulla plays an important role in maintaining body fluid and electrolyte balance and longterm blood pressure homeostasis through its unique structural and functional properties. Among several humoral, paracrine factors or autocoids, angiotensin II (Ang II) has been implicated in the regulation of renal medullary function, including the medullarylpapillary microcirculation, urine concentration, and blood pressure, but the mechanisms by which Ang II exerts influences in the renal medulla are largely unknown. The purpose of this review is to summarize the cellular localization, regulation, and functional properties of Ang II AT1 receptors in the kidney, with special emphasis on type I renomedullary interstitial cells (RMICs) in the renal medulla and cultured RMICs. High densities of AT1 receptors have been localized in type I RMICs in the inner stripe of the outer medulla by high resolution light and electron microscopic autoradiography following in vitro or in vivo labelling, or in cultured RMICs. Furthermore, reverse transcription polymerase chain reaction and Southern blot analysis now confirm that AT1 receptors in cultured RMICs are exclusively of the AT1A subtype. In cultured RMICs, Ang II markedly increases intracellular inositol 1,4,5-triphosphate (IP3) concentration, and stimulates cell proliferation and extracellular matrix synthesis, and these cellular responses are exclusively mediated by AT1 receptors. Considering the co-occurrence of high levels of renin, renin substrate angiotensinogen, and Ang II in the interstitial fluid compartment, and AT1 receptors in type I RMICs of the renal medulla, the AT1 receptor-bearing RMICs may be more responsive to the locally formed interstitial Ang II than to the circulating peptide. Since RMICs also contain the receptors for other vasoactive peptides, such as endothelin (ETA and ETB), natriuretic peptides (NPRA and NPRB), and bradykinin (B2), and synthesize prostaglandins and medullipins, they may serve as an important site for functional interactions between Ang II and other vasoactive peptides in modulating renal medullary function. More studies using different experimental approaches are therefore required to explore and elucidate the functional role of renal interstitial Ang II and AT1 receptors in RMICs in the physiological control of renal medullary function and in the pathophysiology of hypertension and progressive renal diseases. (Hypertens Res 1997; 20: 233-250)

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Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 54%

Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 99%

Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 99%

Section: Ang II Receptor Subtypes In Renal Vasculaturementioning

confidence: 99%

See 2 more Smart Citations

Localization and Functional Properties of Angiotensin II AT1 Receptors in the Kidney. Focus on Renomedullary Interstitial Cells.

et al. 1997

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“…Interstitium of the kidney is about 5-20% of cortex (39). This part is composed of extracellular matrix and interstitial cells, but cannot be seen in light microscopy (40). This part is increased in medulla and reaches 10-40% of medulla (41).…”

Section: Other Parts Of Kidney Tissuementioning

confidence: 99%