ATP stimulation of volume regulation in cultured human astrocytoma cells

Abstract

<p>Introduction: Understanding cell volume control of brain cells will lead to better treatments for patients suffering from brain edema following trauma and other conditions. We examined the role P2Y receptors play in cell volume regulation using cultured 1321Nl human astrocytoma cells. Methods: Cells were removed from the growth surface and suspended in isoosmotic phosphate buffered saline (Iso-PBS) containing (in mM): NaCI (147), KH2P04 (0.5), Na2HP04 (3.2), CaCI2 (1), MgCI2 (0.5), dextrose (5), and KCI (2.7) (pH=7.3, osmolality=290 mOsm) at 37°C for 30 min. Then, cell volumes were determined using the Coulter method at various times after cells were resuspended in Iso-PBS or similar solutions with osmolalities altered by changing the concentration of NaCi. Results: We observed a linear relationship of initial volume versus (osm)-l for cells in osmolalities ranging from 150 mOsm to 600 mOsm with an intercept at 45.3±1.3% of the volume measured in Iso-PBS. Maximal cell swelling in 150 mOsm PBS occurred 3-5 min after suspension. After 10 min and 30 min in this hypoosmotic condition, cell volume had recovered by 18.3±5.1% and 48.4±2.2%, respectively. When 100 11M ATP was added to the 150 mOsm PBS solution, the rate of volume recovery was significantly faster. Conclusion: 132Nl cells demonstrate regulatory volume decrease in hypoosmotic conditions which may be stimulated by purinergic receptors.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 8, 2011</p>