Ultrastructural studies on the secretory process in the epithelioid cells of the juxtaglomerular apparatus

Peter, St.

doi:10.1007/bf00219722

Cited by 29 publications

(13 citation statements)

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“…Renin release has been extensively studied using electron microscopy (17,26,29), radioimmunoassays (2,3,12,22), and patch-clamp techniques (8). Fluorescence imaging with quinacrine was used to identify the renin-containing part of the afferent arteriole (5) and to study the effects of hemorrhage and ischemia on renal renin content (1).…”

mentioning

confidence: 99%

Real-time imaging of renin release in vitro

Peti‐Peterdi

Fintha

Fuson

et al. 2004

American Journal of Physiology-Renal Physiology

106

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lease from juxtaglomerular granular cells is considered the ratelimiting step in activation of the renin-angiotensin system that helps to maintain body salt and water balance. Available assays to measure renin release are complex, indirect, and work with significant internal errors. To directly visualize and study the dynamics of both the release and tissue activity of renin, we isolated and perfused afferent arterioles with attached glomeruli dissected from rabbit kidneys and used multiphoton fluorescence imaging. Acidotropic fluorophores, such as quinacrine and LysoTrackers, clearly and selectively labeled renin granules. Immunohistochemistry of mouse kidney with a specific renin antibody and quinacrine staining colocalized renin granules and quinacrine fluorescence. A low-salt diet for 1 wk caused an approximately fivefold increase in the number of both individual granules and renin-positive granular cells. Time-lapse imaging showed no signs of granule trafficking or any movement, only the dimming and disappearance of fluorescence from individual renin granules within 1 s in response to 100 M isoproterenol. There appeared to be a quantal release of the granular contents; i.e., an all-or-none phenomenon. Using As4.1 cells, a granular cell line, we observed further classic signs of granule exocytosis, the emptying of granule content associated with a flash of quinacrine fluorescence. Using a fluorescence resonance energy transfer-based, 5-(2-aminoethylamino)naphthalene-1-sulfonic acid (EDANS)-conjugated renin substrate in the bath, an increase in EDANS fluorescence (renin activity) was observed around granular cells in response to isoproterenol. Fluorescence microscopy is an excellent tool for the further study of the mechanism, regulation, and dynamics of renin release. multiphoton excitation; fluorescence microscopy; juxtaglomerular apparatus; renin activity; quinacrine THE JUXTAGLOMERULAR APPARATUS (JGA) represents a major structural component of the renin-angiotensin system (RAS) and is one of the most important regulatory sites of renal salt and water conservation and blood pressure maintenance. Release of renin from juxtaglomerular granular cells in the terminal afferent arteriole is considered the rate-limiting step of RAS activation and is precisely controlled by several mechanisms (16,21,24). Reductions in renal perfusion pressure, activation of the sympathetic nervous system, local hormones, and reductions in macula densa salt transport result in increases in circulating and interstitial renin levels that lead to enhanced generation of ANG I with subsequent conversion to ANG II (23,24). ANG II, one of the most potent hypertensive autacoids and the major product of the RAS, exerts its effects on renal vascular and tubular structures, as well as on other organs.

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mentioning

confidence: 99%

Real-time imaging of renin release in vitro

Peti‐Peterdi

Fintha

Fuson

et al. 2004

American Journal of Physiology-Renal Physiology

106

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“…But how is the contact between these two membranes brought about in juxtaglomerular cells? Peter (1976) obtained morphological evidence of deep, channel-like invaginations of the plasma membrane in rat juxtaglomerular granulated cells. He inferred that renin secretion represents an unusual type of exocytosis in which the plasma membrane invaginates towards the granules, thus providing sites for extrusion, instead of the granules moving towards the cell surface prior to release.…”

Section: Mechanisms Of Renin Secretionmentioning

confidence: 92%

Cellular control of renin secretion

Kurtz

Wagner

Reviews of Physiology, Biochemistry and Pharmacology

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“…Although there has been much in vitro evidence that renin is released from JG cells [26,33], no morphological consensus has been reached since there are only a few reports regarding exocytosis or other release mechanisms for renin [70,87,106]. Because of activation of JG cells in experimental hydronephrosis at 1 month after ligation, this is a useful model for investigation of renin release.…”

Section: Experimental Presentation Of Rc Cellsmentioning

confidence: 99%

Comparative Study of Renin-Containing Cells. Histological Approaches.

Kon

1999

The Journal of Veterinary Medical Science

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ABSTRACT. The juxtaglomerular apparatus is known to be the functional unit of renin control. In the present review, the author will describe the comparative characteristics of renin-containing (RC) cells as well as extrarenal distribution, paying special attention to developmental and topographical approaches. The characteristic locality of RC cells suggests that the secretion of renin is performed at a site beside the adventitia or via the glomerular capillaries. Ontogenetical and phylogenetical investigations of RC cells have provided interesting findings on their morphogenesis. Analysis of the endocrine kidney after unilateral obstruction of the ureter provides some findings about the origin of RC cells and the processing of renin granules. Observation of developing adrenal renin suggests that there is important involvement of angiotensin II produced by renin synthesis in the morphogenesis of the adrenal gland in the fetal stage. Coagulating gland (CG) renin is characterized by testosterone-regulated and exocrine mechanisms. Recently, all or some of the components of the renin-angiotensin system (RAS) have been reported to be synthesized and secreted outside of classical organs or tissues. In the future, the real function of local RAS will be clarified by using gene targeting in mice.-KEY WORDS: coagulating gland, development, immunohistochemistry, kidney, renin-angiotensin system.

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Ultrastructural studies on the secretory process in the epithelioid cells of the juxtaglomerular apparatus

Cited by 29 publications

References 13 publications

Real-time imaging of renin release in vitro

Real-time imaging of renin release in vitro

Cellular control of renin secretion

Comparative Study of Renin-Containing Cells. Histological Approaches.

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