Effect of stretch combined with electrical stimulation on the type of sarcomeres produced at the ends of muscle fibers.
Stretching a muscle results in a rapid addition of sarcomeres at the ends of the muscle fibers. The effect of a pattern of electrical stimulation resembling that of a slow motoneuron on the newly formed muscle tissue in a stretched, fast-contracting muscle was investigated. We found that after a period as short as 4 days, the type of sarcomeres which were added on to the ends of the existing myofibrils differed from those in the middle regions of the experimental muscles: there was a much higher proportion of type I and type IIA sarcomeres in the stretch-stimulated ends. This study showed that reprogramming of the synthesis of fiber type-specific contractile proteins can be achieved and detected within a very short time by using electrical stimulation combined with stretch.
D000818:Animals; D004558:Electric Stimulation; D008297:Male; D009119:Muscle Contraction; D009210:Myofibrils / Q000502:physiology*; D011817:Rabbits; D012518:Sarcomeres / Q000502:physiology*