Table II.

Comparison of muscle contractile properties between mTOR and RAmKO mice

MiceControlmTOR/RAmKO% Control
Soleus muscle
mTOR
    Mass (mg)7.6 ± 0.47.5 ± 0.398.7
    Po (mN)a141.6 ± 33.2104.3 ± 24.0c73.6
    sPo (mN/mm2)a187.9 ± 42.0134.5 ± 37.1c71.6
    Pt (mN)a26.4 ± 3.716.2 ± 4.1d61.4
    TTP (ms)a82.7 ± 11.1171.5 ± 73.8d207.4
    RT50% (ms)a131.7 ± 45.3375.4 ± 228.2c285.0
    F20% (ms)a85.1 ± 14.541.1 ± 18.9d48.3
Raptor
    Mass (mg)7.1 ± 0.96.5 ± 0.990.9
    Po (mN)a155.6 ± 24.6141.7 ± 11.091.0
    sPo (mN/mm2)a211.5 ± 38.7212.4 ± 19.3100.4
TA muscle
mTOR
    Mass (mg)37.5 ± 1.232.7 ± 2.2d87.2
    Po (mN)a536.3 ± 100.7332.0 ± 55.4d61.9
    Po (mN)b567.1 ± 79.1359.7 ± 34.8d63.4
    sPo (mN/mg)b15.1 ± 2.211.0 ± 1.4c73.0
    Pt (mN)b106.4 ± 25.860.5 ± 9.5d56.7
    TTP (ms)b31.5 ± 2.442.4 ± 9.3134.6
    RT50% (ms)b33.2 ± 3.858.0 ± 10.9d174.7
    Deficit (%)b−12.7 ± 5.0−56.0 ± 12.9d−340.9
Raptor
    Mass (mg)41.0 ± 2.436.2 ± 1.7d88.5
    Po (mN)b607.1 ± 35.7497.0 ± 55.2d81.9
    sPo (mN/mg)b14.9 ± 1.413.8 ± 1.892.5
    Deficit (%)b−12.0 ± 3.5−12.2 ± 7.31.5
  • Muscle contractile properties of 9-wk-old mTOR and raptor mice were assessed by recording isometric forces in response to electrical stimulation. The following data were measured: muscle mass, Po, sPo, Pt, TTP, RT50%, time taken for maximal twitch tension to fall by 20% (F20%), and the percentage of force deficit following repetitive eccentric contractions (deficit). The data indicate mean ± SD (n > 4 mice/group).

  • a Muscle electrical stimulation.

  • b Nerve electrical stimulation.

  • c P < 0.05.

  • d P < 0.01.