Calcium Clearance Measurement

2020 ◽  
Author(s):  
Keyword(s):  
Calcium Clearance

Renal tubular reabsorption of trace alkaline earths compared with calcium

1965 ◽  
Vol 208 (6) ◽  
pp. 1165-1170 ◽  
Author(s):  
W. Joseph Rahill ◽  
Mackenzie Walser
Keyword(s):  
Protein Binding ◽  
Transport Mechanism ◽  
Tubular Reabsorption ◽  
Constant Infusion ◽  
Constant Power ◽  
Calcium Clearance ◽  
Renal Tubular Reabsorption ◽  
Order Of Magnitude ◽  
Alkaline Earths ◽  
Renal Tubular

Simultaneous clearances of inulin, calcium, and either Be7, Ba140, or Ra226, given by constant infusion, were measured in salt-depleted dogs or dogs undergoing mild saline, mannitol, or sulfate diuresis. Urine-to-plasma ratios of all three cations less than 0.5 were noted, suggesting that all can be actively reabsorbed. Clearances of barium and radium were correlated with calcium clearance, but the clearance of beryllium was unpredictable. Protein binding of beryllium was shown to be of the same order of magnitude as other alkaline earths when errors due to adsorption of Be7 onto containers were minimized. Protein binding of barium averaged 54%. The excreted-to-filtered ratio for barium was a constant power (.54) of the ratio for calcium. The data do not exclude the possibility that these cations are reabsorbed by a common transport mechanism with calcium.

The Effect of Vitamin D on Renal Calcium Clearance

1976 ◽  
pp. 383-388 ◽  
Author(s):  
Felix Bronner ◽  
Ellis E. Golub ◽  
Jan A. Fischer
Keyword(s):  
Vitamin D ◽  
Calcium Clearance

scholarly journals LKB1 Regulates Mitochondria-Dependent Presynaptic Calcium Clearance and Neurotransmitter Release Properties at Excitatory Synapses along Cortical Axons

PLoS Biology ◽  
2016 ◽  
Vol 14 (7) ◽  
pp. e1002516 ◽  
Author(s):  
Seok-Kyu Kwon ◽  
Richard Sando ◽  
Tommy L. Lewis ◽  
Yusuke Hirabayashi ◽  
Anton Maximov ◽  
...  
Keyword(s):  
Neurotransmitter Release ◽  
Excitatory Synapses ◽  
Calcium Clearance ◽  
Presynaptic Calcium

Coupling of Calcium Homeostasis to Axonal Sodium in Axons of Mouse Optic Nerve

2002 ◽  
Vol 88 (2) ◽  
pp. 802-816 ◽  
Author(s):  
Yakov Verbny ◽  
Chuan-Li Zhang ◽  
Shing Yan Chiu
Keyword(s):  
Optic Nerve ◽  
Calcium Homeostasis ◽  
Action Potentials ◽  
Calcium Influx ◽  
Repetitive Nerve Stimulation ◽  
Strongly Coupled ◽  
Sodium Load ◽  
Calcium Clearance ◽  
Calcium Dyes ◽  
Ionophore Monensin

Axonal populations in neonatal and mature optic nerves were selectively stained with calcium dyes for analysis of calcium homeostasis and its possible coupling to axonal Na. Repetitive nerve stimulation causes a rise in axonal [Ca2+]i the posttetanus recovery of which is impeded by increasing the number of action potentials in the tetanus. This effect is augmented in 4-aminopyridine (4-AP; 1 mM), which dramatically increases the calcium and presumably sodium load during the tetanus. Increasing axonal [Na]i with the Na-ionophore monensin (4–50 μM) and ouabain (30 μM) retards posttetanus calcium decline, suggesting that efficient calcium clearance depends on a low level of axonal [Na]i. Posttetanus calcium clearance is not affected by K-mediated depolarization. To further examine coupling between axonal [Na]i and [Ca2+]i, the resting axonal [Ca2+]i was monitored as axonal [Na+]i was elevated with ouabain, veratridine, and monensin. In all cases, elevation of axonal [Na+]i evokes a calcium influx into axons. This influx is unrelated to activation of calcium channels but is consistent with calcium influx via reversal of the Na/Ca exchanger expected as a consequence of axonal [Na+]i elevation. In conclusion, this study demonstrates that calcium homeostasis in the axons of the optic nerve is strongly coupled to axonal [Na+]i in a manner consistent with the Na/Ca exchanger playing a major role in extruding calcium following nerve activity.

Gestational changes in Ca2+ transport across rat placenta and mRNA for calbindin9K and Ca(2+)-ATPase

1992 ◽  
Vol 263 (4) ◽  
pp. R930-R935 ◽  
Author(s):  
J. D. Glazier ◽  
D. E. Atkinson ◽  
K. L. Thornburg ◽  
P. T. Sharpe ◽  
D. Edwards ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Calcium Transport ◽  
Hybridization Analysis ◽  
Northern Hybridization ◽  
Gestational Period ◽  
Beta Actin ◽  
Mrna Ratio ◽  
Calcium Clearance ◽  
Actin Mrna ◽  
Rate Limiting

The unidirectional maternofetal clearance (Kmf) of 45Ca was measured across the rat placenta over the last one-third of gestation. Kmf for 45Ca normalized to its diffusion coefficient in water (Kmf/Dw) increased 72-fold between days 15 and 22 of gestation from 3.5 +/- 0.3 to 253.1 +/- 22.0 cm/g placenta, respectively. At 15 and 18 days of gestation, Kmf/Dw for 45Ca was similar to Kmf/Dw for the paracellular marker [14C]mannitol, but at 21 and 22 days of gestation, Kmf/Dw for 45Ca was significantly higher than Kmf/Dw for [14C]mannitol, indicating that an additional route of transfer, other than diffusion, becomes available to calcium during this period. Northern hybridization analysis demonstrated that rat placental calbindin9K-to-beta-actin mRNA ratio increased 135-fold between 15 and 22 days of gestation and was temporally associated with the gestational increase in Kmf/Dw for 45Ca. In contrast, rat placental Ca(2+)-ATPase-to-beta-actin mRNA ratio increased only two- to threefold over the same gestational period and did not mirror the gestational changes in calcium clearance. These trends suggest that the expression of placental calbindin9K, but not Ca(2+)-ATPase, may be rate limiting to placental calcium transport in the rat.

scholarly journals Remodeling of calcium handling in skeletal muscle through PGC-1α: impact on force, fatigability, and fiber type

2012 ◽  
Vol 302 (1) ◽  
pp. C88-C99 ◽  
Author(s):  
Serge Summermatter ◽  
Raphael Thurnheer ◽  
Gesa Santos ◽  
Barbara Mosca ◽  
Oliver Baum ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Calcium Release ◽  
Ex Vivo ◽  
Fiber Type ◽  
Force Production ◽  
Calcium Handling ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Calcium Clearance

Regular endurance exercise remodels skeletal muscle, largely through the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). PGC-1α promotes fiber type switching and resistance to fatigue. Intracellular calcium levels might play a role in both adaptive phenomena, yet a role for PGC-1α in the adaptation of calcium handling in skeletal muscle remains unknown. Using mice with transgenic overexpression of PGC-1α, we now investigated the effect of PGC-1α on calcium handling in skeletal muscle. We demonstrate that PGC-1α induces a quantitative reduction in calcium release from the sarcoplasmic reticulum by diminishing the expression of calcium-releasing molecules. Concomitantly, maximal muscle force is reduced in vivo and ex vivo. In addition, PGC-1α overexpression delays calcium clearance from the myoplasm by interfering with multiple mechanisms involved in calcium removal, leading to higher myoplasmic calcium levels following contraction. During prolonged muscle activity, the delayed calcium clearance might facilitate force production in mice overexpressing PGC-1α. Our results reveal a novel role of PGC-1α in altering the contractile properties of skeletal muscle by modulating calcium handling. Importantly, our findings indicate PGC-1α to be both down- as well as upstream of calcium signaling in this tissue. Overall, our findings suggest that in the adaptation to chronic exercise, PGC-1α reduces maximal force, increases resistance to fatigue, and drives fiber type switching partly through remodeling of calcium transients, in addition to promoting slow-type myofibrillar protein expression and adequate energy supply.

scholarly journals The Novel PMCA2 Pump MutationTommyImpairs Cytosolic Calcium Clearance in Hair Cells and Links to Deafness in Mice

2010 ◽  
Vol 285 (48) ◽  
pp. 37693-37703 ◽  
Author(s):  
Mario Bortolozzi ◽  
Marisa Brini ◽  
Nick Parkinson ◽  
Giulia Crispino ◽  
Pietro Scimemi ◽  
...  
Keyword(s):  
Hair Cells ◽  
Cytosolic Calcium ◽  
The Novel ◽  
Calcium Clearance
Sign in / Sign up

Export Citation Format

Share Document