Kurbağa izole iskelet kaslarında izometrik sarsı karakterlerinin karşılaştırılması ve kalsiyum iyonunun etkisi

Abstract

X 7. SUMMARY The comparison of the isometric properties of isolated frog skeletal muscles and the effect of Ca2+ ions on these properties. Although it has been known that the role of extracellular Ca2+ on the contraction of the skeleton muscle is negligible, recent investigations found out contrary data. Owing to these current facts, the goal of this study is to search for the impact of the extracellular calcium ions on the periodical twithc parameters of the isolated frog muscles. In our researc we used isolated skeletal muscle preparats provided from both sexes of Rana Ridibunda frogs of 60=70 gr. weight. The isometric muscle twitchs, produced by elektrical stimulus models are recorded in polygraphic system. Then we reckoned the periodical twithc parameters (CT, RT, 1/2 RT, TT) out of recorded ones. We did not determined of differences in twitch properties before fatigue between Gastrrecnemius and extensor digitorum longus muscles. It was found out that in bothXI muscle groups the twitch period in the medium containing calcium was longer than that without calcium. While Gastrecnemius muscle might be fatigue by stimuli between 1-5 Hz. under both media with ör without calcium, extensor digitoram longus muscle was not fatigue under the medium with calcium. Particularly the relaxation parameters of the Gastocnemius muscle whether under the medium containing calcium ör not between 1-5 Hz was longer than those of other muscles. it was also discovered that the isometric twich properties of teh extensor digitorum and gastrecnemius muscles towards 1-5 Hz electrical stimuli models do not vary according to media with/without calcium. in our study the difFerence of twitch parameters between two muscle groups depended upon their trofic position as well as fibre proportion. Lastly we concluded that extracelular calcium ions played an important role in the regulation of calcium release from sarcoplasmic reticulum. Further study is needed in order to understand the real mechanism of this occurrence.