comparative study on the contractile behavior of enervated skeletal muscles of rat and uromastix

Studies regarding the effects of disuse on the skeletal muscles of rat and uromastix were made in view of the differences already reported in the contractile characteristics of the normal skeletal muscles of uromastix [Azeem and Shaikh,1987]. The left hemi - dia phragm of white albino rat and the left gastrocnemius muscles of uromastix were chronically denervated for 21 days In rats, the twitch and tetanic tensions of the denervated muscles showed significant decreases. However, other time dependent parameters were found to be increased significantly. In case of uromastix however, the muscles were not found to be affected by chromic denervation. The contractile behaviour of the denervated muscles of these animals are discussed in terms of morphological and mechanical contraction differences

new analysis of isometric tension curves obtained from hypothermic and hypothermic studies on single skeletal muscle: removal of possible fatigue effect

A new analytical method has been designed for isometric tension curves obtained from hypothermic and hyperthermic studies on single skeletal muscles for the removal of possible fatigue effect. For this purpose, rat diaphragm strips were subjected to hypothermia and the results were compared with a previous study [Shaikh et al., 1979a] to determine whether the previously observed decrease in tetanic tension was temperature dependent or that it was due to fatigue. The results showed that under hypothermic conditions, the twitch and tetanic activity was optimal at 18°C and 30°C respectively with the twitch/tetanus ratios being lower at higher temperatures and vice versa. The new method of analysis designed for the present and the previous isometric tension curves, obtained from muscles subjected to hypothermia and hyperthermia, has demonstrated the actual effect of temperature while excluding the possible fatigue effect