An oscillating intratubular pressure response to alterations in Henle loop flow in the rat kidney

Leyssac, P. P.; Baumbach, L

doi:10.1111/j.1748-1716.1983.tb00015.x

Cited by 93 publications

(65 citation statements)

References 13 publications

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“…5 In these studies, we found that activation of the calcium-sensing receptor produced increases in Ca Interestingly, the frequency of oscillations in perimacular cTAL cell [Ca 2ϩ ] i is remarkably close to that of TGF-dependent oscillations in tubular fluid flow and renal blood flow in anesthetized animals. [12][13][14][15][16][17] We do not have evidence that the increases in DT [Ca 2ϩ ] i contributed to or were associated with the activation of afferent arteriole smooth muscle cell [Ca 2ϩ ] I ; however, these new findings are at least suggestive and should stimulate future research efforts in understanding communication processes between tubule and glomerular structures.…”

Section: Discussionmentioning

confidence: 95%

Oscillating Cortical Thick Ascending Limb Cells at the Juxtaglomerular Apparatus

Komlósi

Banizs

Fintha

et al. 2008

Journal of the American Society of Nephrology

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While studying the intracellular calcium dynamics in cells of the macula densa, the observation was made that tubular epithelial cells located near the macula densa and associated with the renal arterioles exhibit spontaneous Ca 2ϩ oscillations. In this study, the cortical thick ascending limb-distal tubule, with attached glomerulus, was isolated and perfused. At a low luminal sodium chloride concentration, Ca 2ϩ oscillations at a frequency of 63 mHz were observed in tubular cells that were within 100 m of the macula densa plaque using four-dimensional multiphoton microscopy and wide-field fluorescence microscopy with fura-2. The Ca 2ϩ oscillations were absent in the macula densa cells. Spontaneous oscillations in basolateral membrane potential suggested that Ca 2ϩ oscillations occurred, at least in part, through depolarization-induced increases in Ca 2ϩ entry. The amplitude of these Ca 2ϩ oscillations was significantly enhanced by the activation of the Ca 2ϩ -sensing receptor. Increasing the luminal sodium chloride concentration or luminal flow resulted in a significant increase in both the amplitude of Ca 2ϩ oscillations and the intracellular Ca 2ϩ concentration in perimacular cortical thick ascending limb cells. In addition, luminal furosemide attenuated the [NaCl] L -dependent changes in intracellular Ca 2ϩ concentration, but hydrochlorothiazide had no effect. These findings demonstrate that tubular epithelial cells at the perimeter of the macula densa exhibit spontaneous oscillations in intracellular Ca 2ϩ concentration, enhanced by tubular flow and luminal sodium chloride. These oscillatory patterns may play a role in juxtaglomerular signaling.

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Section: Discussionmentioning

confidence: 95%

Oscillating Cortical Thick Ascending Limb Cells at the Juxtaglomerular Apparatus

Komlósi

Banizs

Fintha

et al. 2008

Journal of the American Society of Nephrology

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“…However, in the mid-1980s, experiments by Leyssac and Baumbach 11 and by Holstein-Rathlou and Leyssac 12 demonstrated that the TGF regulation in rat nephrons tends to be unstable and to generate self-sustained oscillations in the tubular pressures and flows with a typical period of 30-40 s. While for normal rats the oscillations had the appearance of a regular self-sustained oscillation with a sharply peaked power spectrum, highly irregular oscillations, displaying a broadband spectral distribution with strong subharmonic components, were observed for spontaneously hypertensive rats. It has subsequently been found that irregular oscillations can be elicited for rats with normal blood pressure, provided that the arterial blood pressure is increased by reducing the blood flow to the other kidney ͑two-kidney, one-clip Goldblatt hypertensive rats͒.…”

Section: Pressure and Flow Control In The Kidneymentioning

confidence: 99%

Synchronization phenomena in nephron–nephron interaction

Holstein‐Rathlou

Yip

Sosnovtseva

et al. 2001

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Experimental data for tubular pressure oscillations in rat kidneys are analyzed in order to examine the different types of synchronization that can arise between neighboring functional units. For rats with normal blood pressure, the individual unit ͑the nephron͒ typically exhibits regular oscillations in its tubular pressure and flow variations. For such rats, both in-phase and antiphase synchronization can be demonstrated in the experimental data. For spontaneously hypertensive rats, where the pressure variations in the individual nephrons are highly irregular, signs of chaotic phase and frequency synchronization can be observed. Accounting for a hemodynamic as well as for a vascular coupling between nephrons that share a common interlobular artery, we develop a mathematical model of the pressure and flow regulation in a pair of adjacent nephrons. We show that this model, for appropriate values of the parameters, can reproduce the different types of experimentally observed synchronization. © 2001 American Institute of Physics. ͓DOI: 10.1063/1.1376398͔The kidneys play an essential role in regulating the blood pressure and maintaining a proper environment for the cells of the body. This control depends to a large extent on mechanisms associated with the individual functional unit, the nephron. However, a variety of cooperative phenomena that arise from interactions among the nephrons may also be important. In-phase synchronization, for instance, where the nephrons simultaneously perform the same regulatory adjustments of the incoming blood flow is likely to produce fast and strong effects in the overall response to changes in the external conditions. Out-ofphase synchronization, on the other hand, will lead to a slower and less pronounced response of the system in the aggregate. The purpose of the present paper is to demonstrate how different forms of synchronization can be observed in the pressure and flow variations for neighboring nephrons. Particularly interesting is the observation of chaotic phase synchronization in rats with high blood pressure. Based on a description of the physiological mechanisms involved in the various regulations, we develop a mathematical model that can account for the experimentally observed synchronization phenomena.

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“…Early experiments by Leyssac and Baumbach 8 and by Leyssac and Holstein-Rathlou 9,10 demonstrated that the feedback regulation could become unstable and generate selfsustained oscillations in the proximal intratubular pressure with characteristic periods of 30-40 s. While for normal rats the oscillations had the typical appearance of a limit cycle, highly irregular oscillations were found for spontaneously hypertensive rats ͑SHR͒. Oscillations were observed for 50%-80% of the investigated nephrons.…”

Section: Introductionmentioning

confidence: 99%

Bifurcation analysis of nephron pressure and flow regulation

Barfred

Mosekilde

Holstein‐Rathlou

1996

Chaos: An Interdisciplinary Journal of Nonlinear Science

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One-and two-dimensional continuation techniques are applied to study the bifurcation structure of a model of renal flow and pressure control. Integrating the main physiological mechanisms by which the individual nephron regulates the incoming blood flow, the model describes the interaction between the tubuloglomerular feedback and the response of the afferent arteriole. It is shown how a Hopf bifurcation leads the system to perform self-sustained oscillations if the feedback gain becomes sufficiently strong, and how a further increase of this parameter produces a folded structure of overlapping period-doubling cascades. Similar phenomena arise in response to increasing blood pressure. The numerical analyses are supported by existing experimental results on anesthetized rats. © 1996 American Institute of Physics. ͓S1054-1500͑96͒02503-7͔The function of the kidneys plays an essential role for the regulation of the blood pressure and hence for the development of cardiovascular diseases. At the same time, the kidneys dispose of a variety of mechanisms to protect their own function against variations in the blood pressure. Experiments on rats have shown that these mechanisms can lead to self-sustained oscillations, period doublings and chaos. Based on a detailed physiological knowledge we have developed a model that can reproduce these findings. A two-parameter bifurcation analysis of the model shows a so-called crossroad structure of overlying period-doubling bifurcations previously observed for one-and two-dimensional mappings.

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An oscillating intratubular pressure response to alterations in Henle loop flow in the rat kidney

Cited by 93 publications

References 13 publications

Oscillating Cortical Thick Ascending Limb Cells at the Juxtaglomerular Apparatus

Oscillating Cortical Thick Ascending Limb Cells at the Juxtaglomerular Apparatus

Synchronization phenomena in nephron–nephron interaction

Bifurcation analysis of nephron pressure and flow regulation

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