The effect of salt adaptation on the permeability and cation selectivity of the goldfish intestinal epithelium

Ellory, J. Clive; Nibelle, J.; Smith, Michael W.

doi:10.1113/jphysiol.1973.sp010222

Cited by 21 publications

(4 citation statements)

References 13 publications

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“…The early stage of adaptation, therefore, probably involves a control over the passive entry of salt into, rather than the active extrusion of salt from, the gallbladder epithelium. This is similar to the effect seen previously in the goldfish intestine, where adaptation to salt has been shown by direct measurement of uptake, to decrease the rate at which sodium enters the mucosa (Ellory, Lahlou & Smith, 1972;Ellory, Nibelle & Smith, 1973).…”

Section: Discussionsupporting

confidence: 81%

Temperature-dependent changes in fluid transport across goldfish gallbladder

1973

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Summary. The temperature dependence of fluid transport across in vitro preparations of goldfish gallbladder was measured using a gravimetric technique. Fluid transport showed a direct dependence on incubation temperature when the adaptation temperature was kept constant. For constant incubation temperature, transport fell as the adaptation temperature rose. The width of intercellular channels varied with incubation and adaptation temperature as expected if fluid were to cross the tissue by this route. The structure of the gallbladder was otherwise unaffected by changes of temperature. Intracellular concentrations of Na, K and C1 also depended on the environmental temperature of the fish. The levels of Na and C1 increased and the level of K decreased, at constant incubation temperature, as the adaptation temperature rose from 8 to 30 ~ These changes took two to three weeks to become apparent while fluid transport regulated within 20 hours of raising the environmental temperature. The osmotic permeability of the gallbladder remained independent of both incubation and adaptation temperature.The outcome of adaptation was to maintain constant both the ionic composition of the epithelium and the rate at which it could transport fluid, when these parameters were measured at incubation temperatures equal to the previous environmental temperature of the fish. The significance of these findings is discussed and a mechanism for regulation postulated which involves an initial regulation of salt entry into the rnucosa followed by long term changes in the pumping ability of newly synthesized cells.The mechanism whereby water is removed from bile held within the gallbladder is now understood in some detail, thanks largely to the work of Diamond and his co-workers (see the review of Diamond, 1968). The active extrusion of salt into intercellular channels creates a standing osmotic gradient which then provides the driving force for fluid movement

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Section: Discussionsupporting

confidence: 81%

Temperature-dependent changes in fluid transport across goldfish gallbladder

1973

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“…times lower than K(Britten & Blank, 1968) and K-stimulated phosphatase from beef brain at 1/10 of the K concentrations(Inturrisi, 1969), throughout the concentration range. Similar 'displacements' of Ti from its expected position in the selectivity sequence occur in other systems as with goldfish intestine mucosal permeability, sequence IV(Ellory, Nibelle & Smith, 1973), and K-channel permeability in nerve axon, sequence IV(Hille, 1973), in both of which Ti shows the highest…”

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confidence: 57%

Thallium and the sodium pump in human red cells

Cavieres¹,

Ellory²

1974

The Journal of Physiology

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SUMMARY1. Thallium (Ti) inhibits the ouabain-sensitive K influx in human red cells in high-Na medium. At 1 mm external K concentration [K.], the ouabain-sensitive K influx decreases steadily with increasing Ti concentration, up to 0-9 mm outside; at 0-17 mM-K., however, Ti stimulates the ouabain-sensitive K influx below 0.1 mM-Ti0 and inhibits it at higher concentrations.2. In a K-free medium in which all except 5 mM-Na is replaced by choline, and into which red cells show zero control ouabain-sensitive Na efflux, Ti is able to support ouabain-sensitive Na efflux up to 2-1 m-mole/l. cells. hr following a sigmoid activation curve which is half-maximal between 0 03 and 0.05 mM-TiO and that follows two-site kinetics up to 0 I mM-Tlo. Beyond 0 15 mm-TiO, the Ti-activated ouabainsensitive Na efflux attained is inhibited slightly.3. When the ouabain-sensitive Na efflux is measured at 5 mM-Na0 and 5 mM-K0, increasing concentrations of Ti have little effect on it, 0.9 mM-TiO inhibiting by some 14 %; in similar conditions, the ouabainsensitive K influx is inhibited by about 40 %.4. The dependence of ouabain-sensitive K influx on external K concentration at 5 mm-Nao, which follows a slightly sigmoid curve in the absence of Ti, changes to hyperbolic at 0-06 mM-Tlo at the same time that ouabain-sensitive K influx is inhibited. The fitted Vmax values for ouabainsensitive K influx are the same in the presence and in the absence of 0x06 mM-Tlo.5. In high-Na cells, loaded by nystatin treatment, the ouabainsensitive K influx measured at 0-2 mM-Nao follows a hyperbolic curve between 0-05 and 0 4 mM-K0, and is inhibited by Ti in a strictly competitive fashion.6. The effects of Ti on ouabain-sensitive Na efflux and ouabainsensitive K influx are interpreted in terms of a high-affinity substitution for K at the external K sites of the Na pump and suggest that in human red cells Ti can be actively transported inwards in exchange for internal Na. J. D. CAVIERES AND J. C. ELLORY 7. Thallium can inhibit about 25 % of the ouabain-insensitive Na efflux into 5 mM-Na0 and part of this inhibition occurs with a high TI-affinity; the ouabain-insensitive K influx is inhibited by Ti both in high-Na and in 5 mm-Na medium, but with a different concentration dependence than the ouabain-insensitive Na effilux.

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“…Although the placenta is the site for respiratory gas exchange in utero , FBMs are detectable at 10 weeks gestational age (Boddy and Mantell, 1973 ; LoMauro and Aliverti, 2016 ). Whilst FBMs do not play a role in gas exchange, they do regulate the degree of lung liquid within the developing lungs, which is critical for normal tissue development and maturation, maintenance of intraluminal pressure and lung liquid volume, as well as the priming and entrainment of the respiratory muscles and neural circuitry for effective postnatal breathing (Harding, 1997 ; Baguma-Nibasheka et al, 2012 ; Koos and Rajaee, 2014 ).…”

Section: Fetal Breathing Movementsmentioning

confidence: 99%

The Consequences of Preterm Birth and Chorioamnionitis on Brainstem Respiratory Centers: Implications for Neurochemical Development and Altered Functions by Inflammation and Prostaglandins

Stojanovska

Miller

Hooper

et al. 2018

Front. Cell. Neurosci.

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Preterm birth is a major cause for neonatal morbidity and mortality, and is frequently associated with adverse neurological outcomes. The transition from intrauterine to extrauterine life at birth is particularly challenging for preterm infants. The main physiological driver for extrauterine transition is the establishment of spontaneous breathing. However, preterm infants have difficulty clearing lung liquid, have insufficient surfactant levels, and underdeveloped lungs. Further, preterm infants have an underdeveloped brainstem, resulting in reduced respiratory drive. These factors facilitate the increased requirement for respiratory support. A principal cause of preterm birth is intrauterine infection/inflammation (chorioamnionitis), and infants with chorioamnionitis have an increased risk and severity of neurological damage, but also demonstrate impaired autoresuscitation capacity and prevalent apnoeic episodes. The brainstem contains vital respiratory centers which provide the neural drive for breathing, but the impact of preterm birth and/or chorioamnionitis on this brain region is not well understood. The aim of this review is to provide an overview of the role and function of the brainstem respiratory centers, and to highlight the proposed mechanisms of how preterm birth and chorioamnionitis may affect central respiratory functions.

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The effect of salt adaptation on the permeability and cation selectivity of the goldfish intestinal epithelium

Cited by 21 publications

References 13 publications

Temperature-dependent changes in fluid transport across goldfish gallbladder

Temperature-dependent changes in fluid transport across goldfish gallbladder

Thallium and the sodium pump in human red cells

The Consequences of Preterm Birth and Chorioamnionitis on Brainstem Respiratory Centers: Implications for Neurochemical Development and Altered Functions by Inflammation and Prostaglandins

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