Regulatory volume decrease in alveolar macrophages: Cation loss is not correlated with changes in membrane recycling
✍ Scribed by Jeanne M. Novak; Peter M. Cala; Diane McVey Ward; Saundra S. Buys; Jerry Kaplan
- Publisher
- John Wiley and Sons
- Year
- 1988
- Tongue
- English
- Weight
- 817 KB
- Volume
- 137
- Category
- Article
- ISSN
- 0021-9541
No coin nor oath required. For personal study only.
✦ Synopsis
Alveolar macrophages regain their normal volume after swelling in hypo-osmotic solutions. This process, termed regulatory volume decrease (RVD), is initiated 3-5 minutes after exposure of cells to hypo-osmotic solutions, and by 30 min, near-normal volumes are attained. Volume decrease does not occur at 0°C or in solutions in which Na+ has been replaced by K f , or CIby the impermeant anion gluconate. These results, as well as direct measurement of intracellular cations, indicate that decreases in cell volume result primarily from the loss of K+ and CIand are similar to RVD in lymphocytes. Kinetic analysis of cation loss, both by directly measuring changes in intracellular cation content and by assaying rubidium efflux, showed that cation loss occurred immediately upon media dilution. The rate of cation loss fit first-order kinetics and preceded both the initiation of volume decrease and the maximum increase in surface receptor number. These results suggest that the cation transporters responsible for RVD are located at the cell surface and that regulation of activity is not dependent on
Osmotic changes
alterations in membrane movement.