RESUMO
Gastrocnemius muscles of Uromastix were used to observe the effects of short term (7 days) immobilization in flexed position. Results demonstrated significantly (P < 0.01) lesser magnitude as well as rate of rise in isometric twitch and tetanic tensions with insignificantly different twitch/tetanus ratio in the immobilized muscles. Both the twitch and tetanus also demonstrated significantly (P<0.01) higher twitch half relaxation and twitch/tetanus half relaxation time ratio. While, immobilized muscles showed insignificantly higher twitch contraction, tetanus half relaxation and duration of active state as well as peak twitch duration, than control ones. These changes in the mechanical contraction parameters were not found to be associated with changes in weight, resting, stretched and shortened length of the immobilized muscles. A comparison of present results with previous work performed on skeletal muscles of Uromastix at longer period (20 days) of immobilization has suggested that Uromastix muscles are no prone to a significant immobilization atrophy. However, decreased mechanical response after immobilization irrespective of the period of immobilization in Uromastix muscles is probably due to a depletion in various substrates involved in muscle mechanics.
