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Cell swelling increases intracellular free [Ca] in cultured toad bladder cells
S M Wong1, M C DeBell, H S Chase
1Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York 10032.
The American Journal of Physiology
|February 11, 1990
Summary
Cell swelling in toad bladder cells significantly increases intracellular calcium concentration ([Ca]i). This rise is due to enhanced calcium entry across the cell membrane, possibly via calcium channels.
Area of Science:
- Cell biology
- Physiology
- Membrane transport
Background:
- Intracellular free calcium concentration ([Ca]i) is crucial for cellular functions.
- Cell swelling can alter cellular homeostasis and signaling pathways.
- Toad bladder cells (TB-M) provide a model for studying epithelial cell responses.
Purpose of the Study:
- To investigate the effect of cell swelling on [Ca]i in cultured toad bladder cells.
- To elucidate the mechanisms underlying the changes in [Ca]i during cell swelling.
Main Methods:
- Cultured toad bladder cells (TB-M) grown as polarized monolayers.
- Measurement of [Ca]i using fura-2 and fluorescence microscopy.
- Manipulation of serosal bathing medium osmolality and ion concentrations.
Main Results:
- A 15% reduction in osmolality caused a rapid increase in [Ca]i from 97 ± 9 nM to 354 ± 88 nM within 10 seconds.
- The swelling-induced [Ca]i increase was independent of extracellular sodium concentration.
- The increase in [Ca]i was abolished by reducing extracellular calcium or adding lanthanum, and partially inhibited by calcium channel blockers (nitrendipine, verapamil).
Conclusions:
- Cell swelling in toad bladder cells leads to a significant increase in intracellular calcium.
- This calcium increase is mediated by enhanced calcium entry across the basolateral membrane.
- The findings suggest the involvement of calcium channels in the swelling-induced calcium influx.