An alternative method for fast/slow motor unit division, tested in various programs of altered physical activity in the rat, and in the cat muscle

• Autorzy: Haluszka A. , Celichowski J. , Krutki P.
• Języki publikacji: EN

Abstrakty

EN

Plasticity of motor unit (MU) contractile properties observed as a result of various forms of altered physical activity or neurological disorders often leads to difficulties in their division into fast and slow types on a basis of standard physiological criteria (sag disappearance, changes of the contraction time). A method to recognize fast or slow MU types on a basis of a profile of tetanic contraction evoked at 20 Hz frequency has been proposed. We evaluated its efficiency in the male and female rats, after several types of a physical training (locomotor training, whole-body-vibration), and after various spinal cord injuries (transection or hemisection). Analogical method was used to distinguish fast and slow MUs in the cat muscle. Functionally isolated MUs of the medial gastrocnemious muscle were investigated, and the 20 Hz Tetanus Index was calculated for each MU as a ratio of the peak force in a response to the last stimulus within the unfused 20 Hz tetanus to the peak force following the first stimulus. For fast MUs values of this index were lower than 2.0, and for slow MUs higher than 2.0 in either group investigated. However in the cat muscle, composed of MUs with considerably longer twitch-time characteristics, the stimulation frequency, which enabled us to receive comparable results was lower (15 Hz) and border value of the index amounted to 5.0.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2013
• Tom: 73
• Numer: Suppl.1
• Opis fizyczny: p.32

Twórcy

autor

Haluszka A.

• Department of Neurobiology, University School of Physical Education, Poznan, Poland

autor

Celichowski J.

• Department of Neurobiology, University School of Physical Education, Poznan, Poland

autor

Krutki P.

• Department of Neurobiology, University School of Physical Education, Poznan, Poland