Mechanical response of lizard skeletal muscles to disuse: II. Effect of short-term denervation

The gastrocnemius muscles of Uromastix hardwickii were used to determine the effects of the absence of neural influence on them. For this purpose, the muscles were denervated for 7 days and were used to record isometric twitch and tetanus. The contraction parameters thus obtained from the denervated muscles were then compared with their own controls. The isometric tensions and time dependent tension parameters were significantly lower in the denervated muscles. The time dependent parameters, peak duration in twitch and duration of active state in twitch were however, found to be unaffected by short-term denervation with the exception of twitch/tetanus half relaxation time ratio, which was significantly higher in the denervated muscles. The denervation effects observed on the mechanical contraction behaviour of the gastrocnemius muscle have been discussed in terms of electrical excitation, excitation-contraction coupling and cross bridge interaction.