Mechanism of active chloride secretion by shark rectal gland: role of Na-K-ATPase in chloride transport

Silva, P.; Stoff, Jeffrey S.; Field, Michael; Fine, Leon G.; Forrest, Jeffrey Yi‐Lin; Epstein, Franklin H.

doi:10.1152/ajprenal.1977.233.4.f298

Cited by 196 publications

(147 citation statements)

References 41 publications

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“…The only effect is to prolong the response. These results are similar to those found in the shark rectal gland (Silva et al 1977), and perhaps depend on an interaction with the cyclic AMP system. Theophylline's complex interaction with alkaline phosphatase is another possibility (McComb et al 1979).…”

Section: Schmidt-nielsen and F/inge (1958) First Suggested That An Orsupporting

confidence: 89%

“…This is not true in the sea turtle which also has a lachrymal salt gland, but these animals are difficult to obtain at a size useful in the laboratory. The lachrymal gland of Malaclemys is too small to use for perfusion as has been done with the rectal gland of elasmobranch (Silva et al 1977), and attempts at isolating lachrymal gland tubules for in vitro perfusion have only been partially successful. Thus a potentially good study system has not as yet been too useful, to the point that Peaker and Linzell (1975) conclude in their review on salt glands that next to nothing is known about the physiology of salt secretion in reptilian salt gland systems.…”

Section: Discussionmentioning

confidence: 99%

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Effects of salt loading on salt gland function in the euryhaline turtle,Malaclemys terrapin

Cowan

1981

J Comp Physiol B

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Summary. The estuarine turtle, Malaclemys terrapinis able to ionregulate when acclimated to fresh water, 55% sea water or 100% (full strength) sea water, but when in 100% sea water it does not volume regulate successfully. Orbital gland secretions collected by a new eye cup method are very low in animals from all three salinities without salt load. After salt loading the animals from all three groups produce an orbital gland secretion with a sodium concentration greater than sea water. The concentration of ions and kinetics of the response are similar in all three groups. Orbital gland secretion returns to control preload levels well before the injected load is excreted. There is no correlation between the plasma sodium concentration and any of the parameters of the orbital gland response. There is also no correlation between the concentration of sodium in the tear fluid or the rate of sodium excretion and the level of K+-stimulated p-nitrophenylphosphatase activity in the gland. Some of these unexpected results may relate to the estuarine habitat occupied by Malaclemys. there is more knowledge about osmoregulation (see Discussion). One pertinent fact is that Malaclernys progressively lose weight when in sea water for short term (Bentley et al. 1967) or for long terms (Cowan 1970). This might indicate that the animal is not osmoregulating perfectly, and that salt gland secretions are not hypertonic to sea water.To study the function of the salt gland and its role in osmoregulation, an eyecup method was devised which avoids some of the problems of the earlier methods (see Discussion) and which allows measurement of ion concentrations in the secretions.

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Section: Schmidt-nielsen and F/inge (1958) First Suggested That An Orsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Effects of salt loading on salt gland function in the euryhaline turtle,Malaclemys terrapin

Cowan

1981

J Comp Physiol B

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“…The pioneering work of Lundberg in 1957 (20) described a Cl − -dependent saliva secretion process in which transcellular Cl − transport is coupled to fluid secretion (25). This pump-leak fluid secretion model predicts that Cl − influx occurs through a basolateral "pump" and Cl − ions are extruded via an apical "leak" (26).…”

Section: Discussionmentioning

confidence: 99%

A fluid secretion pathway unmasked by acinar-specific Tmem16A gene ablation in the adult mouse salivary gland

Catalán

Kondo

Peña-Münzenmayer

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Activation of an apical Ca 2+ -activated Cl − channel (CaCC) triggers the secretion of saliva. It was previously demonstrated that CaCCmediated Cl − current and Cl − efflux are absent in the acinar cells of systemic Tmem16A (Tmem16A Cl − channel) null mice, but salivation was not assessed in fully developed glands because Tmem16A null mice die within a few days after birth. To test the role of Tmem16A in adult salivary glands, we generated conditional knockout mice lacking Tmem16A in acinar cells (Tmem16A −/− ). Ca 2+ -dependent salivation was abolished in Tmem16A −/− mice, demonstrating that Tmem16A is obligatory for Ca 2+ -mediated fluid secretion. However, the amount of saliva secreted by Tmem16A −/− mice in response to the β-adrenergic receptor agonist isoproterenol (IPR) was comparable to that seen in controls, indicating that Tmem16A does not significantly contribute to cAMP-induced secretion. Furthermore, IPR-stimulated secretion was unaffected in mice lacking Cftr (Cftr ΔF508/ΔF508 ) or ClC-2 (Clcn2 −/− ) Cl − channels. The time course for activation of IPR-stimulated fluid secretion closely correlated with that of the IPR-induced cell volume increase, suggesting that acinar swelling may activate a volume-sensitive Cl − channel. Indeed, Cl − channel blockers abolished fluid secretion, indicating that Cl − channel activity is critical for IPR-stimulated secretion. These data suggest that β-adrenergic-induced, cAMP-dependent fluid secretion involves a volume-regulated anion channel. In summary, our results using acinar-specific Tmem16A −/− mice identify Tmem16A as the Cl − channel essential for muscarinic, Ca 2+ -dependent fluid secretion in adult mouse salivary glands.acinar cell | secretion | Cl − channel | Tmem16A/Ano1 | Cftr channel

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“…They took the standard model of electrolyte secretion developed by Silva et al (45), and showed that secretion rates would be optimal if 11-25% of the total cellular K ϩ conductance was placed in the apical membrane. In their models, when peak secretion rates were attained with optimal proportions of apical K ϩ channels, the predicted values of luminal K ϩ were 16 -28 mM.…”

Section: Functional Significancementioning

confidence: 99%

An Inwardly Rectifying Potassium Channel in Apical Membrane of Calu-3 Cells

Krouse

Joo

et al. 2004

Journal of Biological Chemistry

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Patch clamp methods and reverse transcription-polymerase chain reaction (RT-PCR) were used to characterize an apical K ؉ channel in Calu-3 cells, a widely used model of human airway gland serous cells. In cell-attached and excised apical membrane patches, we found an inwardly rectifying K ؉ channel (Kir). The permeability ratio was P Na /P K ‫؍‬ 0.058. In 30 patches with both cystic fibrosis transmembrane conductance regulator and Kir present, we observed 79 cystic fibrosis transmembrane conductance regulator and 58 Kir channels. The average chord conductance was 24.4 ؎ 0.5 pS (n ‫؍‬ 11), between 0 and ؊200 mV, and was 9.6 ؎ 0.7 pS (n ‫؍‬ 8), between 0 and 50 mV; these magnitudes and their ratio of ϳ2.5 are most similar to values for rectifying K ؉ channels of the Kir4.x subfamilies. We attempted to amplify transcripts for Kir4.1, Kir4.2, and Kir5.1; of these only Kir4.2 was present in Calu-3 lysates. The channel was only weakly activated by ATP and was relatively insensitive to internal pH. External Cs ؉ and Ba 2؉ blocked the channel with K d values in the millimolar range. Quantitative modeling of Cl ؊ secreting epithelia suggests that secretion rates will be highest and luminal K ؉ will rise to 16 -28 mM if 11-25% of the total cellular K ؉ conductance is placed in the apical membrane (Cook, D. I., and Young, J. A. (1989) J. Membr. Biol. 110, 139 -146). Thus, we hypothesize that the K ؉ channel described here optimizes the rate of secretion and is involved in K ؉ recycling for the recently proposed apical H ؉ -K ؉ -ATPase in Calu-3 cells.

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Mechanism of active chloride secretion by shark rectal gland: role of Na-K-ATPase in chloride transport

Cited by 196 publications

References 41 publications

Effects of salt loading on salt gland function in the euryhaline turtle,Malaclemys terrapin

Effects of salt loading on salt gland function in the euryhaline turtle,Malaclemys terrapin

A fluid secretion pathway unmasked by acinar-specific Tmem16A gene ablation in the adult mouse salivary gland

An Inwardly Rectifying Potassium Channel in Apical Membrane of Calu-3 Cells

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