Control mechanisms of amino acid-mediated cell volume regulation in salinity-stressed molluscs

✍ Scribed by Pierce, Sidney K. ;Amende, Lynn M.

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 941 KB
• Volume: 215
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402150304

✦ Synopsis

Abstract

The mechanisms of cell volume regulation in molluscs have been examined in detail in only a few species. While generalizations must be made with some caution until additional species have been tested, the following mechanism has emerged. When stressed with a decreased external salinity the cells of osmoconforming bivalves swell for a period of time and then recover toward the original cell volume. The volume recovery is effected by an efflux of intracellular free amino acids which act as osmotic solute. While the drop in external osmolality initiates the efflux, the duration of the efflux (restoration of normal amino acid permeability) relies on the activity of a Ca^2+^ – Mg^2+^ requiring ATPase. In addition, cell volume regulation and the amino acid efflux are accompanied by an alteration in the number of membrane associated particles per unit of membrane area. While the relationship between the ATPase activity, membrane associated particles and amino acid permeability is not yet clear, there is good evidence that the mechanism of cell volume control resides with the cell membrane in these animals.