| Autor: |
Herrera, Francisco C., Rodriguez, Arlec, López, Ildemaro, Weitzmann, Henny, Zanders, I. Perey |
| Zdroj: |
Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology; July 1986, Vol. 156 Issue: 4 p591-597, 7p |
| Abstrakt: |
Maintenance of intracellular ion contents and their relations to transmembrane potential were studied in tentacles ofCondylactis gigantea. Tentacles leached at 2°C in 10 mMK+ and 2 mM K+ artificial seawaters (10K ASW and 2K ASW) with and without 2 MM ouabain, and in 0K ASW, lost cell K+ and gained Na+. Rewarming to 25°C in 10K ASW resulted in a marked accumulation of K+ and extrusion of Na+ in tentacles leached in 10K ASW and in 0K ASW. Initial rate of Na+ extrusion was twice the initial rate of K+ accumulation, suggesting a pump coupling ratio of 2. In tentacles leached and rewarmed in 2K ASW, no net reaccumulation of K+ and little net extrusion of Na+ was observed; i.e., the pump just kept pace with the leaks. Ouabain inhibited K+ reaccumulation and Na+ extrusion. This effect was less marked in 10K ASW than in 2K ASW confirming, in anemone tentacles, the well documented ouabain-K+ antagonism observed in other systems. In no case did Ki+/K0+ equal Cl0-/Cli-; therefore, the distribution of these ions did not fit a Donnan distribution. Transmembrane potential difference was -22±3 mV in 10K ASW at 25°C. It fitted a modified Nernst equation which includes the pump coupling ratio and a Na+ to K+ permeability ratio of 0.31. |
| Databáze: |
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