| Autor: |
Huddart, H., Williams, A. |
| Zdroj: |
Journal of Comparative Physiology; Oct1974, Vol. 94 Issue 4, p331-338, 8p |
| Abstrakt: |
Calcium uptake of sarcoplasmic reticulum (SR) isolated from Carcinus skeletal muscle was examined under control conditions and in the presence of 5 mM quinine and 10 mM caffeine. Quinine was without significant effect on SR intrinsic calcium but caffeine caused a release of about 17% of this calcium compartment. Both alkaloids depressed ATP-promoted calcium binding by the SR, caffeine inducing a greater depression of binding. In addition, both alkaloids were able to release calcium from previously loaded SR. It is concluded that caffeine-induced release of intrinsic calcium may contribute to the rise in myoplasmic calcium associated with caffeine contracture, but caffeine action on SR labile calcium is the major basis for contracture-induction. In the case of quinine, electron microscopic evidence suggests that this drug acts on the mitochondrial calcium compartment of the muscle fibre as well as on the SR. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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