Related Experiment Video
Updated: Aug 11, 2026
13:47
TIRFM and pH-sensitive GFP-probes to Evaluate Neurotransmitter Vesicle Dynamics in SH-SY5Y Neuroblastoma Cells: Cell Imaging and Data Analysis
Published on: January 29, 2015
Regulatory volume decrease and intracellular Ca2+ in murine neuroblastoma cells studied with fluorescent probes
J Altamirano1, M S Brodwick, F J Alvarez-Leefmans
1Departamento de Neurobiología, Instituto Mexicano de Psiquiatría, México 14370, D.F. México.
The Journal of General Physiology
|August 5, 1998
Summary
Calcium ions (Ca2+) do not appear essential for triggering regulatory volume decrease (RVD) in neural cells, even though RVD is often accompanied by a transient Ca2+ increase. This finding challenges the established role of Ca2+ in cell volume regulation.
Area of Science:
- Cell Biology
- Physiology
- Biochemistry
Background:
- Regulatory Volume Decrease (RVD) is a critical cellular process for maintaining homeostasis in response to osmotic stress.
- The role of intracellular calcium (Ca2+) as a second messenger in mediating RVD has been previously suggested but not definitively proven.
- Neural cell lines offer a model system to investigate complex cellular signaling pathways.
Purpose of the Study:
- To investigate the necessity of Ca2+ in triggering and regulating RVD in murine neural cell lines.
- To simultaneously measure intracellular Ca2+ levels and cell volume changes during RVD.
- To elucidate the precise role of Ca2+ in the inactivation of RVD.
Main Methods:
- Utilized novel microspectrofluorimetric techniques for simultaneous single-cell measurement of intracellular Ca2+ ([Ca2+]i) and cell volume.
- Employed fura-2 for ratiometric [Ca2+]i measurement and calcein as an independent volume probe.
- Applied hyposmotic challenges and Ca2+ chelation (EGTA, BAPTA) to assess RVD responses.
Main Results:
- Hyposmotic stress induced RVD, accompanied by a transient increase in [Ca2+]i that preceded RVD.
- [Ca2+]i increase correlated with the degree of hyposmotic challenge and cell swelling.
- Ca2+ chelation attenuated but did not abolish RVD, indicating a Ca2+-independent component.
- Ca2+-independent RVD occurred even with decreased [Ca2+]i, and Ca2+ restoration did not affect RVD rate or extent.
- RVD and [Ca2+]i increases were attenuated upon repeated hyposmotic challenges, irrespective of Ca2+ presence.
Conclusions:
- Simultaneous measurements demonstrate that an increase in intracellular Ca2+ is not essential for initiating RVD or its inactivation in these neuroblastoma cells.
- The observed attenuation of RVD upon Ca2+ chelation may be due to secondary effects or a requirement for optimal, rather than essential, RVD.
- These findings necessitate a re-evaluation of the role of Ca2+ as a primary mediator of RVD in neural cells.
