Seawater Teleosts: Evidence for a Sodium-Potassium Exchange in the Branchial Sodium-Excreting Pump

Maetz, J.

doi:10.1126/science.166.3905.613

Cited by 92 publications

(36 citation statements)

References 18 publications

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“…No model has been found in the literature which would explain the findings of the studies presented here, although bidirectional fluxes have been documented in the intestine (22)(23)(24), kidney (25)(26)(27)(28)(29), frog skin (30), toad bladder (31), and gill (32). The apparent independence of mucosal to serosal and serosal to mucosal flux demonstrated here and in the studies of Visscher et al (22,23), and the unequal unidirectional osmotically driven fluxes of sucrose through the frog skin (33), and of water through the frog intestine (24), both suggest that different pathways are involved, but offer no insight about whether those pathways are transcellular or intercellular.…”

Section: Discussionmentioning

confidence: 62%

Intestinal transport of water and electrolytes during extracellular volume expansion in dogs

Higgins¹,

Blair²

1971

J. Clin. Invest.

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A B S T R A C T The effects of extracellular fluid volume expansion on intestinal transport of salts and water were studied in dogs by perfusing loops of bowel in vivo. Saline loading caused depression of duodenal and jejunal absorption with net secretion of salt and water into the lumen. Studies of unidirectional transport of 'Na' revealed that the negative net sodium flux was due primarily, and perhaps exclusively, to increased serosal to mucosal transport, for mucosal to serosal sodium transport was not changed during volume expansion. Net transport of water and potassium paralleled net sodium flux. Administration of deoxycorticosterone did not affect the intestinal response to saline loading. Hemodilution, accomplished by equilibrating the dogs' blood with a reservoir of saline, did not affect intestinal absorption, but isotonic, iso-oncotic expansion of the extracellular fluid produced by reinfusing the saline-blood mixture from the reservoir resulted in negative net transport of water, sodium, and potassium by the duodenum. It is suggested that the small bowel is capable of secreting salts and water through intercellular spaces, and that this process is stimulated by extracellular fluid volume expansion.

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Section: Discussionmentioning

confidence: 62%

Intestinal transport of water and electrolytes during extracellular volume expansion in dogs

Higgins¹,

Blair²

1971

J. Clin. Invest.

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“…170) became known 35 years ago, it was proposed that apical Na ϩ -K ϩ -ATPase-mediated Na ϩ extrusion across the branchial epithelium, because, for example, removal of external K ϩ or external application of ouabain inhibited Na ϩ efflux, measured radioisotopically (e.g., Refs. 190,197,424). This proposition of apical Na ϩ -K ϩ -ATPase extruding cellular Na ϩ was rendered untenable when Karnaky demonstrated unequivocally that Na ϩ -K ϩ -ATPase was restricted to the basolateral membrane of the MRC in the branchial epithelium of the killifish (349), and this localization has now been confirmed for a variety of species, including elasmobranchs (e.g., Refs.…”

Section: Nacl Secretion In Marine Teleostsmentioning

confidence: 94%

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

Evans¹,

Piermarini²,

Choe³

2005

Physiological Reviews

2,278

1,788

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The fish gill is a multipurpose organ that, in addition to providing for aquatic gas exchange, plays dominant roles in osmotic and ionic regulation, acid-base regulation, and excretion of nitrogenous wastes. Thus, despite the fact that all fish groups have functional kidneys, the gill epithelium is the site of many processes that are mediated by renal epithelia in terrestrial vertebrates. Indeed, many of the pathways that mediate these processes in mammalian renal epithelial are expressed in the gill, and many of the extrinsic and intrinsic modulators of these processes are also found in fish endocrine tissues and the gill itself. The basic patterns of gill physiology were outlined over a half century ago, but modern immunological and molecular techniques are bringing new insights into this complicated system. Nevertheless, substantial questions about the evolution of these mechanisms and control remain.

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“…Currently, the models for NaCl secretary mechanisms by the teleost gill Cl-cell propose an important role for Na+, K+-activated ATPase, either directly (Maetz, 1969(Maetz, , 1971 or indirectly (Kirschner, 1977;Silva, Solomon, Spokes & Epstein, 1977 (Karnaky et al 1976). Since the gill and opercular epithelium chloride cells are identical in ultrastructure (Karnaky & Kinter, 1977), it is reasonable to assume that this ATPase is located in the tubular membranes of the opercular epithelium chloride cells.…”

Section: Discussionmentioning

confidence: 99%

Active chloride transport in the in vitro opercular skin of a teleost (Fundulus heteroclitus), a gill‐like epithelium rich in chloride cells

Degnan¹,

Karnaky²,

Zadunaisky³

1977

The Journal of Physiology

194

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K. J. DEGNAN AND OTHERS net Cl-blood side to seawater side flux of 162-8 isA/cm2 which was not statistically different (P > 0.70) from the mean short-circuit current of 158-6 + 163 ,uA/cm2 for these flux studies. The mean Na+ blood side to seawater side flux was 32-2 + 3-3 ,uA/cm2 and the mean Na+ seawater side to blood side flux was 34-8 + 4-1 isA/cm2, resulting in no significant (P > 0*20) net flux of this cation. Similar results were obtained with short-circuited epithelia of seawater-adapted fish when bathed on both sides with Ringer and gassed with 95 % 02/5 % CO2.5. Ouabain (105 M), furosemide (10-3 M), thiocyanate (10-2 M), adrenaline (1I0 M), and anoxia (100 % N2) decreased the short-circuit current 92*7, 85-0, 45-3, 62-6, and 83'3 % respectively. Theophylline (104 M) stimulated the short-circuit current 54-9 %. Increasing the HC03-concentration in the bathing solutions had a stimulatory effect on the short-circuit current and the potential difference across epithelia from seawater-adapted fish.6. The opercular epithelia of freshwater-adapted F. heteroclitU8, when bathed on both sides with Ringer, displayed a mean short-circuit current of 94-1 + 10 4 #sA/cm2, a mean transepithelial potential difference of 14-8 + 1*9 mV (blood side positive), and a mean d.c. resistance of 169-0 + 14-0 Q. cm2 (mean + S.E. of mean; n = 20). Isotope flux studies across these short-circuited epithelia revealed a net Cl-blood side to freshwater side flux of 95-2 + 16-1 ,uA/cm2 and no significant net flux of Na+.7. The opercular epithelia of 200 % seawater-adapted F. heteroclitus, when bathed on both sides with Ringer, displayed a mean short-circuit current of 33-5 + 8-5 IzA/cm2, a mean transepithelial potential difference of 10*5 + 2*5 mV (blood side positive), and a mean transepithelial d.c. resistance of 440 7 + 62*6 Q.cm2 (mean + S.E. of mean n = 18). Isotope flux studies across these short-circuited epithelia revealed a net Cl-blood side to seawater side flux of 96-2 + 51*5 ,uA/cm2 and a net Na+ blood side to seawater side flux of 65'3 + 28-6 ,uA/cm2.

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Seawater Teleosts: Evidence for a Sodium-Potassium Exchange in the Branchial Sodium-Excreting Pump

Cited by 92 publications

References 18 publications

Intestinal transport of water and electrolytes during extracellular volume expansion in dogs

Intestinal transport of water and electrolytes during extracellular volume expansion in dogs

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

Active chloride transport in the in vitro opercular skin of a teleost (Fundulus heteroclitus), a gill‐like epithelium rich in chloride cells

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