Water permeability through biological membranes by isotopic effects of fluorescence and light scattering

Lawaczeck, Rüdiger

doi:10.1016/s0006-3495(84)84184-3

Cited by 52 publications

(25 citation statements)

References 27 publications

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“…Five raw tracings were averaged, normalized to initial fluorescence, and fitted to a single-exponential curve using Biokine Software (Molecular Kinetics, Pullman, WA). P DW was calculated using the following relation: P DW = 1/[τ ex (S/ V)], where τ ex is the exchange time (1/k), and S/V is the surface area to volume ratio of BBMV (12). In our calculations, the diameter of BBMV was assumed to be 200 nm, as previously measured in our laboratory in neonates and adults (24).…”

Section: P Dw -Measurementsmentioning

confidence: 99%

Glucocorticoids increase osmotic water permeability (P_f) of neonatal rabbit renal brush border membrane vesicles

Mulder¹,

Chakravarty²,

Haddad³

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

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Glucocorticoids increase osmotic water permeability (P f ) of neonatal rabbit renal brush border membrane vesicles. there is an increase in renal brush border membrane vesicle (BBMV) osmotic water permeability and a parallel increase in aquaporin-1 (AQP1) protein abundance. The mechanisms responsible for these changes remain unknown. Because serum glucocorticoid levels rise postnatally and have previously been linked to other maturational changes in renal function, we examined the effects of glucocorticoids on osmotic (P f ) and diffusional (P DW ) water permeability and AQP1 protein abundance of renal BBMV. Neonatal rabbits were treated with dexamethasone (10 μg/100 g) for three days and compared with control neonates and adults. P f and P DW were measured at 20°C with a stopped-flow apparatus using light-scattering and aminonaphthalene trisulfonic acid (ANTS) fluorescence, respectively. P f was significantly higher in BBMV from dexamethasonetreated neonates compared with vehicle-treated neonates, but remained lower than in BBMV from adults (P < 0.05). P DW in dexamethasone and vehicle-treated neonatal BBMV was lower than in adult BBMV. P f /P DW ratio increased from neonate (5.1 ± 0.3) to dexamethasone (7.0 ± 0.1) and adult BBMV (6.3 ± 0.1). AQP1 expression was increased by dexamethasone treatment to adult levels. Membrane fluidity, which is inversely related to generalized polarization (GP) of steadystate laurdan fluorescence, was significantly higher in neonatal BBMV than both dexamethasone and adult BBMV (GP: neonate 0.285 ± 0.002, dexamethasone treatment 0.302 ± 0.006, and adult 0.300 ± 0.005; P < 0.05). These combined results show that dexamethasone-treatment during days 4-7 of life increases BBMV water permeability despite a decrease in membrane fluidity. This occurs by increasing channel-mediated water transport, as reflected in an increase in AQP1 protein abundance and a higher P f /P DW ratio. This mimics the maturational changes and suggests a physiological role for glucocorticoids in maturation of proximal tubule water transport.

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Section: P Dw -Measurementsmentioning

confidence: 99%

Glucocorticoids increase osmotic water permeability (P_f) of neonatal rabbit renal brush border membrane vesicles

Mulder¹,

Chakravarty²,

Haddad³

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

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“…The vesicle dispersions were subjected to the osmotic shock 60 min after their preparation. [24,63] The halftime is defined as the Equation (2). A sample was deemed stable if it remained monodispersed and the average size of the vesicles was constant.…”

Section: Microscopiesmentioning

confidence: 99%

Membrane Properties of Archæal Macrocyclic Diether Phospholipids

Dannenmuller¹,

Akita²,

Eguchi³

et al. 2000

Chem. Eur. J.

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Several biophysical properties of four synthetic archñal phospholipids [one polyprenyl macrocyclic lipid A and three polyprenyl double-chain lipids (B, C, D) bearing zero, one or four double bonds in each chain] were studied using differential scanning calorimetry, electron and optical microscopies, stopped-flow/light scattering and solidstate 2 H-NMR techniques. These phospholipids gave a variety of self-organized structures in water, in particular vesicles and tubules. These assemblies change in response to simple thermal convection. Some specific membrane properties of these archñal phospholipids were observed: They are in a liquidcrystalline state over a wide temperature range; the dynamics of their polyprenyl chains is higher than that of n-acyl chains; the water permeability of the membranes is lower than that of n-acyl phospholipid membranes. It was also found that macrocyclization remarkably improves the barrier properties to water and the membrane stability. This may be related to the adaptation of Methanococcus jannaschii to the extreme conditions of the deep-sea hydrothermal vents.

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“…We estimated granule Pj using the H20/D20 exchange method described by Lawaczeck (1984) in which the intensity of scattered or transmitted light is an instantaneous function of intravesicular H20/D20 composition. Granules (125 k~g/ml) in 75 mOsm D20 buffer were diluted fivefold with isosmotic H20 buffer in the stopped-flow apparatus.…”

Section: Discussionmentioning

confidence: 99%

Very low osmotic water permeability and membrane fluidity in isolated toad bladder granules

Verkman

Masur

1988

J. Membrain Biol.

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Osmotic water permeability of the apical membrane of toad urinary epithelium is increased greatly by vasopressin (VP) and is associated with exocytic addition of granules and aggrephores at the apical surface. To determine the physiological role of granule exocytosis, we measured the osmotic water permeability and membrane fluidity of isolated granules, surface membranes and microsomes prepared from toad bladder in the presence and absence of VP. Pf was measured by stopped-flow light scattering and membrane fluidity was examined by diphenylhexatriene (DPH) fluorescence anisotropy. In response to a 75 mM inward sucrose gradient, granule size decreased with a single exponential time constant of 2.3 +/- 0.1 sec (SEM, seven preparations, 23 degrees C), corresponding to a Pf of 5 x 10(-4) cm/sec; the activation energy (Ea) for Pf was 17.6 +/- 0.8 kcal/mole. Under the same conditions, the volume of surface membrane vesicles decreased biexponentially with time constants of 0.13 and 1.9 sec; the fast component comprised approximately 70% of the signal. Granule, surface membrane and microsome time constants were unaffected by VP. However, in surface membranes, there was a small decrease (6 +/- 2%) in the fraction of surface membranes with fast time constant. DPH anisotropies were 0.253 (granules), 0.224 (surface membranes) and 0.190 (microsomes), and were unaffected by VP. We conclude: (1) granules have among the lowest water permeabilities of biological membranes, (2) granule water permeability is not altered by bladder pretreatment with VP, (3) granule membrane fluidity is remarkably lower than that of surface and microsomal membranes, and (4) rapid water transport occurs in surface membrane vesicles. The unique physical properties of the granule suggests that apical exocytic addition of granule membrane may be responsible for the low water permeability of the unstimulated apical membrane.

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Water permeability through biological membranes by isotopic effects of fluorescence and light scattering

Cited by 52 publications

References 27 publications

Glucocorticoids increase osmotic water permeability (P_f) of neonatal rabbit renal brush border membrane vesicles

Glucocorticoids increase osmotic water permeability (P_f) of neonatal rabbit renal brush border membrane vesicles

Membrane Properties of Archæal Macrocyclic Diether Phospholipids

Very low osmotic water permeability and membrane fluidity in isolated toad bladder granules

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Water permeability through biological membranes by isotopic effects of fluorescence and light scattering

Cited by 52 publications

References 27 publications

Glucocorticoids increase osmotic water permeability (Pf) of neonatal rabbit renal brush border membrane vesicles

Glucocorticoids increase osmotic water permeability (Pf) of neonatal rabbit renal brush border membrane vesicles

Membrane Properties of Archæal Macrocyclic Diether Phospholipids

Very low osmotic water permeability and membrane fluidity in isolated toad bladder granules

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Glucocorticoids increase osmotic water permeability (P_f) of neonatal rabbit renal brush border membrane vesicles

Glucocorticoids increase osmotic water permeability (P_f) of neonatal rabbit renal brush border membrane vesicles