Abstract
The sea water (SW)-adapted euryhaline Platichthys flesus, and the marine Serranus exchange about 50% of their internal sodium with the external sodium per hour. This rate of exchange decreases with decreasing salinity of the adaptation medium. When the flounder is transferred from SW to FW an instantaneous 90% reduction of the Na and Cl outflux is observed. About 30 min later a second, progressive, reduction occurs. The outflux reductions appear to result from two types of regulatory mechanisms reducing gill permeability and preventing excessive salt loss. The first reduction corresponds to independent "Na- and Cl-free effects" as shown by transfers to artificial media containing either Na or Cl with an impermeant co-ion. The pattern of simultaneous rapid variations of Na influx and outflux for a range of salinity changes in flounder adapted to SW, ½ SW, or ¼ SW has been studied. The data are compatible with the hypothesis of an exchange diffusion mechanism characterized by a coupling of both unidirectional fluxes. The affinity of the exchange diffusion carrier for sodium has been measured (Km ≃ 400 mM). The delayed reduction would result from a progressive diminution of the quantity of carrier available but without modification of its affinity for sodium. When the stenohaline marine perch is transferred from SW to FW, a 40% reduction of the outflux is observed. But it is not the result of an exchange diffusion effect as it is related to the external osmolarity change and not to the NaCl concentration change. Furthermore no delayed reduction is observed after transfer into FW. This transfer is accompanied by a heavy loss of electrolytes resulting in a rapid decline of the plasma electrolyte level and death. A comparative survey of the relative importance of these regulatory mechanisms has been made.
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Selected References
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- ANDERSEN B., USSING H. H. Solvent drag on non-electrolytes during osmotic flow through isolated toad skin and its response to antidiuretic hormone. Acta Physiol Scand. 1957 Jun 8;39(2-3):228–239. doi: 10.1111/j.1748-1716.1957.tb01425.x. [DOI] [PubMed] [Google Scholar]
- ARVY L., FONTAINE M., GABE M. [The hypothalamo-pitultary neurosecretory system of teleosts]. J Physiol (Paris) 1959 Nov-Dec;51:1031–1085. [PubMed] [Google Scholar]
- COOPERSTEIN I. L., HOGBEN C. A. Ionic transfer across the isolated frog large intestine. J Gen Physiol. 1959 Jan 20;42(3):461–473. doi: 10.1085/jgp.42.3.461. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DICK D. A., LEA E. J. NA FLUXES IN SINGLE TOAD OOCYTES WITH SPECIAL REFERENCE TO THE EFFECT OF EXTERNAL AND INTERNAL NA CONCENTRATION ON NA EFFLUX. J Physiol. 1964 Oct;174:55–90. doi: 10.1113/jphysiol.1964.sp007474. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DURBIN R. P., KITAHARA S., STAHLMANN K., HEINZ E. EXCHANGE DIFFUSION OF CHLORIDE IN FROG GASTRIC MUCOSA. Am J Physiol. 1964 Dec;207:1177–1180. doi: 10.1152/ajplegacy.1964.207.6.1177. [DOI] [PubMed] [Google Scholar]
- EDELMAN I. S., YOUNG H. L., HARRIS J. B. Effects of corticosteroids on electrolyte metablism during osmoregulation in teleosts. Am J Physiol. 1960 Oct;199:666–670. doi: 10.1152/ajplegacy.1960.199.4.666. [DOI] [PubMed] [Google Scholar]
- GARCIAROMEU F., MAETZ J. THE MECHANISM OF SODIUM AND CHLORIDE UPTAKE BY THE GILLS OF A FRESH-WATER FISH, CARASSIUS AURATUS. I. EVIDENCE FOR AN INDEPENDENT UPTAKE OF SODIUM AND CHLORIDE IONS. J Gen Physiol. 1964 Jul;47:1195–1207. doi: 10.1085/jgp.47.6.1195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HARRIS E. J. THE DEPENDENCE OF EFFLUX OF SODIUM FROM FROG MUSCLE ON INTERNAL SODIUM AND EXTERNAL POTASSIUM. J Physiol. 1965 Apr;177:355–376. doi: 10.1113/jphysiol.1965.sp007597. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KEYNES R. D. SOME FURTHER OBSERVATIONS ON THE SODIUM EFFLUX IN FROG MUSCLE. J Physiol. 1965 May;178:305–325. doi: 10.1113/jphysiol.1965.sp007629. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KEYNES R. D., SWAN R. C. The effect of external sodium concentration on the sodium fluxes in frog skeletal muscle. J Physiol. 1959 Oct;147:591–625. doi: 10.1113/jphysiol.1959.sp006264. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lange R., Fugelli K. The osmotic adjustment in the euryhaline teleosts, the flounder, Pleuronectes flesus L. and the three-spined stickleback, Gasterosteus aculeatus L. Comp Biochem Physiol. 1965 Jul;15(3):283–292. doi: 10.1016/0010-406x(65)90132-5. [DOI] [PubMed] [Google Scholar]
- MAETZ J., GARCIAROMEU F. THE MECHANISM OF SODIUM AND CHLORIDE UPTAKE BY THE GILLS OF A FRESH-WATER FISH, CARASSIUS AURATUS. II. EVIDENCE FOR NH4 ION/NA ION AND HCO3 ION/C1 ION EXCHANGES. J Gen Physiol. 1964 Jul;47:1209–1227. doi: 10.1085/jgp.47.6.1209. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MAETZ J. Les échanges de sodium chez le poisson Carassius auratus L.; action d'un inhibiteur de l'anhydrase carbonique. J Physiol (Paris) 1956;48(6):1085–1099. [PubMed] [Google Scholar]
- MULLINS L. J., FRUMENTO A. S. The concentration dependence of sodium efflux from muscle. J Gen Physiol. 1963 Mar;46:629–654. doi: 10.1085/jgp.46.4.629. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MULLINS L. J. Osmotic regulation in fish as studied with radioisotopes. Acta Physiol Scand. 1950 Dec;21(4):303–314. doi: 10.1111/j.1748-1716.1950.tb00738.x. [DOI] [PubMed] [Google Scholar]
- TOSTESON D. C., HOFFMAN J. F. Regulation of cell volume by active cation transport in high and low potassium sheep red cells. J Gen Physiol. 1960 Sep;44:169–194. doi: 10.1085/jgp.44.1.169. [DOI] [PMC free article] [PubMed] [Google Scholar]