الفهرس | Only 14 pages are availabe for public view |
Abstract This work is an attempt to clarify the effect of different does of caffeine on the frog s heart contractions as well as its effect on the sodium , potassium and calcium contents in both the ventricular muscle and the whole frog s heart. The results : 1-The enhanced release of calcium from intracellular stores . 2-the inhibitory action of caffeine on phosphodiestrase activity which destroys cyclic AMP thereby , leading to a rapid elevation of cyclic AMP which increases contractile force. 3-Increasing the sensitivity of the contractile protein to calcium |