| Autor: |
Costa, Charles J., Pierce, Sidney K. |
| Zdroj: |
Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology; June 1983, Vol. 151 Issue: 2 p133-144, 12p |
| Abstrakt: |
Glycera dibranchiata red coelomocytes regulate cell volume during hypoosmotic stress by reducing the intracellular concentration of certain osmotically active solutes, principally free amino acids (FAA) and K+. The volume regulatory mechanisms found in other species, especially the bivalve molluscs, are sensitive to changes in external divalent cation concentrations and the depletion of intracellular ATP. TheGlycera coelomocyte volume regulatory mechanism also requires divalent cations, but the requirement is not specific; either Ca2+ or Mg2+ will suffice. Deletion of both Ca2+ and Mg2+ from the external medium caused leakage of both FAA and K+ from the coelomocytes. The presence of the cellular ATP synthesis inhibitor DNP potentiated the volume regulatory response. The enhanced volume regulation was caused by a potentiated decrease of intracellular K+ content while the salinity induced FAA efflux was unaffected. Incubation of the coelomocytes with ouabain did not affect volume regulation, indicating that control of intracellular K+ during hypoosmotic stress does not depend on the Na+-K+-ATPase. Thus, the volume regulatory mechanisms in theGlycera coelomocytes utilize two types of solute, FAA and K+, and separate permeability mechanisms that interact to control the solute contents during hypoosmotic stress. |
| Databáze: |
Supplemental Index |
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