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Potentiation of regulatory volume decrease by a p2-like receptor and arachidonic acid in american alligator
Chloe Wormser1, Shruti A Pore, Alina B Elperin
1Department of Biology, Lake Forest College, IL 60045, USA.
The Journal of Membrane Biology
|July 6, 2011
Summary
American alligator red blood cells use P2 receptors and arachidonic acid (AA) for regulatory volume decrease (RVD). These mechanisms are crucial for cell volume recovery after hypotonic stress, involving calcium signaling.
Area of Science:
- Cellular Physiology
- Membrane Transport
- Biochemistry
Background:
- Red blood cells (RBCs) must maintain cell volume homeostasis.
- Regulatory Volume Decrease (RVD) is a critical cellular response to osmotic stress.
- The specific mechanisms of RVD in non-mammalian vertebrates like alligators are not fully understood.
Purpose of the Study:
- To investigate the role of P2 receptors and arachidonic acid (AA) in the RVD of American alligator RBCs.
- To elucidate the signaling pathways involved in volume regulation in alligator erythrocytes.
- To determine the contribution of calcium (Ca2+) to the RVD process.
Main Methods:
- Osmotic fragility was assessed using optical methods.
- Mean cell volume was measured via electronic sizing.
- Intracellular Ca2+ concentration changes were monitored using fluorescence microscopy.
- Pharmacological agents targeting P2 receptors and phospholipase A2 (PLA2) were employed.
Main Results:
- Inhibitors of P2 receptors (e.g., suramin, PPADS) and PLA2 (e.g., ONO-RS-082) blocked RVD and Ca2+ influx.
- Arachidonic acid (AA) and its analog ETYA promoted volume recovery and counteracted inhibitory effects.
- Specific P2 receptor agonists (ATPγS, α,β-methylene-ATP, Bz-ATP) stimulated RVD, while others (2-methylthio-ATP, UTP) had no effect.
Conclusions:
- A P2-like receptor system is present and activated in American alligator RBCs, stimulating RVD.
- Arachidonic acid (AA) plays a significant role in facilitating volume recovery during RVD.
- Calcium signaling is integral to the P2 receptor-mediated RVD process in these cells.
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