Micropuncture study of renal excretion of water, K, Na, and Cl in Necturus

Bott, P. A.

doi:10.1152/ajplegacy.1962.203.4.662

Cited by 56 publications

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“…The mean proximal TF/P K ratio of 1.8 observed in Necturus is in good agreement with the published data of Oken and Solomon (5) and Khuri and co-workers (9), but distinctly different from that reported by Bott (2). The TF/P K ratios were distinctly higher in Necturus than in rats or dogs, with eight ratios 2.0 or higher.…”

Section: Proximal Transtubular Potential Differences (Et)supporting

confidence: 83%

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Micropuncture Study of Potassium Concentration in Proximal Tubule of Dog, Rat, and Necturus*

Watson¹,

Clapp²,

Berliner³

1964

J. Clin. Invest.

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A number of investigators (1-9) have recently studied the potassium concentration in the proximal tubule of rat and Necturus. Unfortunately, there are significant differences in the results obtained by different observers. The general conclusion, however, that potassium is reabsorbed against an electrochemical gradient in the proximal tubule of the rat seems justified. Furthermore, if one compares the ratio of the concentration of potassium in tubule fluid to that in plasma (TF/P K) to the corresponding ratio for inulin, potassium appears to be extensively reabsorbed from the proximal tubule.The study reported in this paper was undertaken in an attempt to define the mechanism by which potassium is handled in the proximal tubule of the dog nephron. It was made possible by the development of a sensitive ultramicromethod for the determination of potassium in biological fluids and the adaptation of micropuncture techniques to the study of renal function in dog (10). The concentrations of inulin and potassium were determined in the same samples of proximal tubule fluid. In separate sets of experiments, proximal transtubular potential differences were also determined. The concentrations of inulin and potassium in tubule fluid were compared with the respective concentrations in plasma in order to evaluate net potassium reabsorption, and the TF/P K ratio was compared with equilibrium ratios calculated from the transtubular potential by the Nernst equation.The results of this study differ quantitatively, although not qualitatively, from those reported by others using rat and Necturus as experimental * Submitted for publication July 12, 1963; accepted November 26, 1963. Presented in part at the 55th Annual Meeting of the American Society for Clinical Investigation, April 28, 1963. t Special Public Health Fellow. animals. To determine whether this difference was related to species differences or to methodology, a limited number of proximal TF/P K ratios were also determined in rats and Necturus. MethodsStudies were performed on male and female mongrel dogs weighing from 9 to 15 kg. The dogs were anesthetized by rapid injection of 200 mg of sodium pentothal administered intravenously as a 2.5% solution in distilled water; small additional doses were administered from time to time to maintain the desired level of anesthesia. The left kidney was exposed through a flank incision, and indwelling catheters were inserted into the ureter of the experimental kidney, the foreleg vein, and the femoral vein. Methods of exposing and supporting the kidney for micropuncture as well as the techniques of tubule fluid collection and identification have previously been reported (10). The samples of tubule fluid were generally 0.03 to 0.05 IAI in volume and were collected in 5 minutes or less.In all dog experiments, 15-minute urine collection periods for the determination of inulin and potassium clearances were obtained while tubule fluid samples were being collected. After appropriate priming and sustaining infusions of inulin ha...

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Section: Proximal Transtubular Potential Differences (Et)supporting

confidence: 83%

“…A number of investigators (1)(2)(3)(4)(5)(6)(7)(8)(9) have recently studied the potassium concentration in the proximal tubule of rat and Necturus. Unfortunately, there are significant differences in the results obtained by different observers.…”

mentioning

confidence: 99%

Micropuncture Study of Potassium Concentration in Proximal Tubule of Dog, Rat, and Necturus*

Watson¹,

Clapp²,

Berliner³

1964

J. Clin. Invest.

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“…VTE was somewhat lower in vivo, on average -6 mV (Hoshi, Suzuki & Itoi, 1981; Cohen, Giebisch, Hansen, Teuscher & Wiederholt, 1984) to -15 mV (Teulon & Anagnostopoulos, 1982a), though on occasion VTE reached -35 mV in late portions of this segment (Teulon & Anagnostopoulos, 1982a). Initial determinations of intraluminal ion concentrations along the distal tubule of NecturUs in vivo revealed a substantial axial decline of luminal Na' and Cl-concentrations, consistent with the observed net NaCl absorption along this segment (Bott, 1962); subsequent work confirmed the decrease of Na+ concentration (Wiederholt, Sullivan & Giebisch, 1971; Garland, Henderson & Brown, 1975;Persson & Persson, 1983) and of total electrolyte concentration (Hoshi et al 1981) along the amphibian distal tubule. Tubule to plasma K+ concentration ratio showed variability, but it was essentially lower than 1-00 in the second half of the distal tubule of Necturus (Bott, 1962); this ratio was found to decline from -1P50 to 0-80 along the distal tubule of Amphiuma, (Wiederholt et al 1971) or display a large scatter and remain close to 1 00 in the second half of this segment in Necturus (Garland et al 1975).…”

Section: Introductionmentioning

confidence: 68%

“…Cl-has been shown to be absorbed along the entire length of the distal tubule (Bott, 1962). Since the transepithelial electrochemical potential difference for Clfavours paracellular back-diffusion, Cl-absorption must be exclusively transcellular.…”

Section: Chloridementioning

confidence: 99%

“…Since water is absorbed in the amphibian distal tubule (Bott, 1962;Wiederholt et al 1971;Garland et al 1975), the decrease of luminal Na+ and Cl-concentrations longitudinally indicates that they are reabsorbed in this segment, including its late portion. K+ is normally absorbed in the l.d.t., but secretion is also possible under certain conditions (Wiederholt et al 1971).…”

Section: Introductionmentioning

confidence: 99%

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Cell and luminal activities of chloride, potassium, sodium and protons in the late distal tubule of Necturus kidney.

Anagnostopoulos

Planelles

1987

The Journal of Physiology

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SUMMARY1. Double-barrelled (selective vs. conventional) microelectrodes were used to assess the steady-state activities (a) of the ions Cl-, K+, Na+ and H' in peritubular blood capillaries (abld) and in cell (ace11) and lumen (alum) of the late distal tubule2. acl1, acm and abl were 5-5 + 0-3, 11P8 + 1I0 and 70 5 + 0-1 mm, respectively. They were used to compute the chemical potentials for Cl-across the three diffusive barriers of the tissue. Basolateral and apical membrane potentials were -74-3 + 1 1 and -60-1+2-0 mV, respectively (cell negative); the lumen was thus negative with respect to blood, by 13-6 + 1-5 mV. The electrochemical potential difference (e.p.d.) for Cl-of 42 mV across the apical membrane opposes Cl-absorption, implying active apical Cl-uptake, since Cl-is known to be absorbed in the l.d.t. Basolateral Cl-exit is favoured by an e.p.d. of 10 mV.3. aKe1 a Km and abl were 65-8 + 0-8, 2-5 + 0-1 and 2-5 + 0-1 mm, respectively. The electrochemical distribution of K+ indicates that K+ absorption, if present, proceeds against an adverse apical e.p.d. of 18 mV. Basolateral K+ distribution is close to its electrochemical equilibrium, suggesting high K+ permeability at this membrane.4. aea was 9 0 +0-4 mm, abd 71-0+0-3 mm, and a Na was approximated at about 9 mm. Diffusive Na+ entry from lumen to cell is favoured by an e.p.d. close to 65 mV. Basolateral Na+ exit must be active, since it proceeds against an e.p.d. of 130 mV.5. Cell, luminal and blood pH were 7-14 + 0 03, 6-52 + 0-08 and 7-37 + 0 04, respectively. The luminal electrochemical potential of H+ is higher than that of cell (by 91 mV) and blood (by 34 mV) indicating that proton secretion into the lumen must be active.6. The e.p.d. of each ion across the epithelium opposes, by its orientation, the established direction of net transepithelial ion transport, suggesting that the shunt pathway may serve only for back-diffusion.* The authors' names are in alphabetical order.

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Comparative Physiology of the Kidney

Dantzler

1992

Comprehensive Physiology

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The sections in this article are: Morphological Relationships Initial Process in Urine Formation Filtration of Fluid by Glomeruli Regulation of Number of Filtering Nephrons and of SNGFR Secretion of Fluid by Tubules Transport of Inorganic Ions By Tubules Sodium and Chloride Potassium Calcium Phosphate Magnesium and Sulfate Transport of Fluid by Tubules Fluid Absorption Fluid Secretion Transport of Organic Substances by Tubules Glucose Amino Acids Urea Organic Acids and Anions (Other Than Amino Acids, Urate, and Lactate) Urate Lactate Organic Cations Diluting and Concentrating Processes Range of Urine Osmolality Process and Sites of Dilution Regulation of Changes in Urine Osmolality Integrative Summary of Some Renal Functions Fishes Amphibians Reptiles Birds

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Micropuncture study of renal excretion of water, K, Na, and Cl in Necturus

Cited by 56 publications

References 0 publications

Micropuncture Study of Potassium Concentration in Proximal Tubule of Dog, Rat, and Necturus*

Micropuncture Study of Potassium Concentration in Proximal Tubule of Dog, Rat, and Necturus*

Cell and luminal activities of chloride, potassium, sodium and protons in the late distal tubule of Necturus kidney.

Comparative Physiology of the Kidney

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