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Trichloroethylene interactions with muscle cells
1Central Institute of Occupational Medicine, Dept. of Work Physiology, Berlin, Germany.
Abstract:
The toxic effect of trichlorethylene (TCE) was investigated on isolated muscles prepared from frog and rats. Twitch and tetanic contractions as well as caffeine-induced contractures, were recorded. Trichloroethylene at a concentration of 0.25-4.0 mM depressed the force development of both twitch and tetanic tension in a dose-dependent manner. This effect was not influenced by the type of muscle. As TCE shortened the time to peak of twitch contractions, it may alter the Ca2+ binding kinetics. Subthreshold caffeine concentrations applied after pre-exposure to TCE (1 or 2mM) induced contractures. The same TCE exposure enhanced regular caffeine contractures through increasing the speed of tension development and the absolute force. Exposure to 5 or 10 mM TCE did not affect the first caffeine-induced contracture but enhanced the potency of the second caffeine dose given 15 min after the first. The results suggest that the interaction of TCE with membrane sites is responsible for Ca2+ release for contractile processes.
Insights
Trichloroethylene (TCE) exposure impairs muscle contraction force in a dose-dependent way. However, TCE enhances caffeine-induced muscle contractions, suggesting complex interactions with calcium release mechanisms.
Area of Science:
- Muscle physiology
- Toxicology
- Pharmacology
Background:
- Trichloroethylene (TCE) is an industrial solvent with known toxic effects.
- Its specific impact on muscle contractility and calcium handling remains incompletely understood.
Purpose of the Study:
- To investigate the toxic effects of trichloroethylene on isolated muscle contractility.
- To elucidate the mechanisms underlying TCE's influence on calcium-mediated muscle responses.
Main Methods:
- Isolated frog and rat muscles were used to record twitch, tetanic, and caffeine-induced contractions.
- Muscles were exposed to varying concentrations of TCE (0.25-10 mM).
Main Results:
- TCE depressed twitch and tetanic tension in a dose-dependent manner, independent of muscle type.
- TCE altered calcium binding kinetics, shortening the time to peak contraction.
- TCE exposure enhanced caffeine-induced contractures, increasing tension development speed and force.
Conclusions:
- Trichloroethylene exerts dose-dependent toxic effects on muscle force generation.
- TCE appears to interact with membrane sites, influencing calcium release critical for muscle contraction.