Fast and slow skeletal muscles: simultaneous in vitro study.
Simultaneous study of the function of fast and slow twitch skeletal muscles in the same in vitro preparation has obvious advantages. Equipment, method and technique are described for study of the soleus (slow) and extensor digitorum longus (fast) muscles from the mouse, and the problems involved in preparing and standardizing these studies are discussed. For nearly maximum function to be obtained from both muscles, careful attention must be given to the stimulus parameters used. Three separate studies were necessary to determine the appropriate stimulus duration, frequency and rest interval between the stimulus trains. The results indicate that for study of tetanic tension and rate of tension development of these muscles from the C57 NAB strain of mice at 20C the most satisfactory stimulus parameters are : duration 2 msec, frequency 100 pulses per second and duration of the stimulus train 700 msec. Rest interval between stimulus trains was two minutes as problems developed with rest intervals less than two minutes or greater than four minutes.
D000818:Animals; D004558:Electric Stimulation; D051379:Mice; D008815:Mice, Inbred Strains; D009119:Muscle Contraction; D009132:Muscles / Q000502:physiology*; D013997:Time Factors