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Relation between isometric force and stimulus rate in cat's hindlimb motor units of different twitch contraction time

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Summary

The relation between isometric force and rate (or pulse interval) of repetitive stimulation was studied for 77 motor units from m. peroneus longus of the cat. The units were activated by constant-frequency bursts of 1 s, and the stimulus interval needed for producing half the maximum tension was strongly correlated to twitch contraction time (twitch CT, non-potentiated values 13–42 ms). This remained true for comparisons within groups of fast and slow units respectively (fast/slow classification according to criteria of Burke et al. 1973). A mean contractile force of half maximum amplitude (0.5 Po) was produced by repetitive stimuli with a pulse interval of about 1.5 CT in fast and 2 CT in slow units. Among both kinds of unit, however, these stimulus rates corresponded to pulse intervals of about 1.4 times the half-relaxation time of the twitch. At half-maximum force, the rise of tension per Hz rise of stimulus frequency was about 2.5% Po for fast and 5.8% Po for slow units. Fast-twitch fatigue-sensitive (FF) and twitch fatigue-resistant (FR) units showed similar tension-frequency relations. Comparisons to results from m. gastrocnemius medialis showed that, for corresponding types of fast units (FF units), the twitch CT tended to be about 25% longer for gastrocnemius than for peroneus. The stimulus rate needed for a half-maximum contraction was, however, not lower for FF units from gastrocnemius than for those from the peroneus muscle.

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References

  • Baldissera F, Campadelli P (1977) How motoneurones control development of muscle tension. Nature 268: 146–147

    Google Scholar 

  • Buller AJ, Lewis DM, Ridge RMAP (1965) Some electrical characteristics of fast and slow twitch skeletal muscle fibres in the cat. J Physiol (Lond) 180: 29–30P

    Google Scholar 

  • Burke RE, Levine DN, Tsairis P, Zajac FE (1973) Physiological types and histochemical profiles in motor units of the cat gastrocnemius. J Physiol (Lond) 234: 723–748

    Google Scholar 

  • Burke RE, Rudomin P, Zajac FE (1976) The effect of activation history on tension production by individual muscle units. Brain Res 109: 515–529

    Google Scholar 

  • Burke RE, Tsairis P (1974) The correlation of physiological properties with histochemical characteristics in single muscle units. Ann NY Acad Sci 228: 145–159

    Google Scholar 

  • Close RI (1972) Dynamic properties of mammalian skeletal muscles. Physiol Rev 52: 129–197

    Google Scholar 

  • Cooper S, Eccles JC (1930) The isometric responses of mammalian muscles. J Physiol (Lond) 69: 377–385

    Google Scholar 

  • Hoffer JA, O'Donovan MJ, Pratt CA, Loeb GE (1981) Discharge patterns of hindlimb motoneurons during normal cat locomotion. Science 213: 466–468

    Google Scholar 

  • Kernell D (1965a) High-frequency repetitive firing of cat lumbosacral motoneurones stimulated by long-lasting injected currents. Acta Physiol Scand 65: 74–86

    Google Scholar 

  • Kernell D (1965b) The limits of firing frequency in cat lumbosacral motoneurones possessing different time course of afterhyper-polarization. Acta Physiol Scand 65: 87–100

    Google Scholar 

  • Kernell D (1966) The repetitive discharge of motoneurones. In: Granit R (ed) Muscular afferents and motor control. Nobel Symposium I. Almqvist & Wiksell, Stockholm, pp 351–362

    Google Scholar 

  • Kernell D (1979) Rhythmic properties of motoneurones innervating muscle fibres of different speed in m.gastrocnemius medialis of the cat. Brain Res 160: 159–162

    Google Scholar 

  • Kernell D, Ducati A, Sjöholm H (1975) Properties of motor units in the first deep lumbrical muscle of the cat's foot. Brain Res 98: 37–55

    Google Scholar 

  • Kernell D, Eerbeek O, Verhey BA (1983) Motor unit categorization on basis of contractile properties: an experimental analysis of the composition of the cat's m. peroneus longus. Exp Brain Res 50: 211–219

    Google Scholar 

  • McDonagh JC, Binder MD, Ranking RM, Stuart DG (1980) A commentary on muscle unit properties in cat hindlimb muscles. J Morphol 166: 217–230

    Google Scholar 

  • Rack PMH, Westbury DR (1969) The effects of length and stimulus rate on tension in the isometric cat soleus muscle. J Physiol (Lond) 204: 443–460

    Google Scholar 

  • Spector SA, Gardiner PF, Zernicke RF, Roy RR, Edgerton VR (1980) Muscle architecture and force-velocity characteristics of cat soleus and medial gastrocnemius: implications for motor control. J Neurophysiol 44: 951–960

    Google Scholar 

  • Wuerker RB, McPhedran AM, Henneman E (1965) Properties of motor units in a heterogenous pale muscle (m. gastrocnemius) of the cat. J Neurophysiol 28: 85–99

    Google Scholar 

  • Zajac FE, Young JL (1980a) Properties of stimulus trains producing maximum tension-time area per pulse from single motor units in medial gastrocnemius muscle of the cat. J Neurophysiol 43: 1206–1220

    Google Scholar 

  • Zajac FE, Young JL (1980b) Discharge properties of hindlimb motoneurons in decerebrate cats during locomotion induced by mesencephalic stimulation. J Neurophysiol 43: 1221–1235

    Google Scholar 

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Kernell, D., Eerbeek, O. & Verhey, B.A. Relation between isometric force and stimulus rate in cat's hindlimb motor units of different twitch contraction time. Exp Brain Res 50, 220–227 (1983). https://doi.org/10.1007/BF00239186

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