Related Experiment Videos
Maitotoxin-induced free Ca changes in single rat hepatocytes
N M Woods1, C J Dixon, T Yasumoto
1Department of Applied Biology, The University of Central Lancashire, Preston, UK. n.m.woods@uclan.ac.uk
Cellular Signalling
|January 5, 2000
Summary
Maitotoxin causes a slow rise in intracellular calcium in rat hepatocytes, dependent on external calcium. This calcium increase is preceded by accelerated calcium entry, differing from other stimuli.
Area of Science:
- Cell Biology
- Toxicology
- Biochemistry
Background:
- Maitotoxin is a potent marine toxin known to affect cellular calcium levels.
- Understanding maitotoxin's mechanism is crucial for cell signaling research.
Purpose of the Study:
- To investigate maitotoxin-induced changes in intracellular free calcium (Ca2+) in rat hepatocytes.
- To elucidate the mechanism of maitotoxin-induced calcium mobilization.
Main Methods:
- Utilized bioluminescent and fluorescent indicators (e.g., Fura-2 dextran) to monitor free Ca2+.
- Performed manganese-induced quench experiments to assess calcium entry rates.
- Conducted imaging experiments and combined stimuli (hormonal + maitotoxin) for comparative analysis.
Main Results:
- Maitotoxin induced a slow, sustained increase in free Ca2+ after a significant lag phase.
- The calcium increase was extracellular calcium-dependent and inhibited by calcium chelation or nickel.
- Accelerated calcium entry was observed during the late lag phase, preceding the Ca2+ rise.
- Maitotoxin-induced calcium mobilization differed from glycogenolytic stimuli.
- Some cells showed Ca2+ oscillations despite a rising intracellular Ca2+ level when exposed to combined stimuli.
Conclusions:
- Maitotoxin triggers a unique pathway for intracellular calcium increase, distinct from typical signaling.
- The findings shed light on the complex mechanisms of maitotoxin's action and calcium transient generation.