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Titolo:
ELECTROGENIC ACTION OF CALCIUM ON CRAYFISH GILL
Autore:
KIRSCHNER LB;
Indirizzi:
WASHINGTON STATE UNIV,DEPT ZOOL PULLMAN WA 99164 AUGUST KROGH INST,COMPARAT PHYSIOL LAB COPENHAGEN DENMARK
Titolo Testata:
Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology
fascicolo: 3, volume: 164, anno: 1994,
pagine: 215 - 221
SICI:
0174-1578(1994)164:3<215:EAOCOC>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
AUSTROPOTAMOBIUS-PALLIPES LEREBOULLET; CONCENTRATION-DEPENDENCE; SALMO-GAIRDNERI; RAINBOW-TROUT; MOULT STAGE; TRANSPORT; SODIUM; FLUXES; POTENTIALS; CHANNELS;
Keywords:
GILL POTENTIAL; TRANSEPITHELIAL POTENTIAL DIFFERENCE; CALCIUM TRANSPORT; CRAYFISH GILL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
25
Recensione:
Indirizzi per estratti:
Citazione:
L.B. Kirschner, "ELECTROGENIC ACTION OF CALCIUM ON CRAYFISH GILL", Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology, 164(3), 1994, pp. 215-221

Abstract

When intact crayfish are in an ion-poor medium (KCl, 0.1 mmol.l(-1) KHCO3, 0.1 mmol.l(-1)) there is a large potential difference (transepithelial potential difference), -20 to -40 mV (hemolymph negative), across the gills. Addition of Ca2+ to the medium is followed by a rapid change in transepithelial potential difference to near 0 mV. The transepithelial potential difference showed a non-linear dependence on [Ca2](out) with a limiting value of +2 to +10 mV at >1 mmol.1(-1). The concentration generating a half-maximum transepithelial potential difference change (15-20 mV) was 0.1 to 0.2 mmol.l(-1). Three other alkalineearth ions were also electrogenic; Ba2+ caused slightly larger transepithelial potential difference changes, Sr2+ and Mg2(+) were a little less effective. It has been suggested that the transepithelial potential difference in ion-poor medium (in fish) is due to the diffusive efflux of NaCl across the gills, with a Cl-/Na+ permeability ratio of <1. Evidence is presented that this might be the case in crayfish. The electrogenic effect of Ca2+ might then be due to its effect on gill permeability to Na+ and Cl- such that the permeability ratio increased andapproached unity as the transepithelial potential difference approached 0. However, this was shown to be unlikely. An alternative explanation for Ca2+ dependence of the transepithelial potential difference is that active inward Ca2+ transport is electrogenic.

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Documento generato il 07/07/20 alle ore 12:09:22