Sex differences in motor unit contractile properties of the rat soleus muscle

• Autorzy: Drzymala-Celichowska H. , Krutki P. , Celichowski J.
• Języki publikacji: EN

Abstrakty

EN

The soleus muscle has unique physiological characteristics, as a typical slow-twitch muscle, composed predominantly of slow motor units (MUs). In this study we examined electrophysiologically functionally isolated MUs of male and female adult Wistar rats. It was revealed that the mean mass of the soleus muscle in males was approximately by 80% bigger than in females, however, a relation of the muscle-to-body mass was higher for females. No differences were observed with respect to the MU twitch forces, but the maximum tetanus forces were substantially lower for female rats, what significantly influenced higher twitch-to tetanus ratios in females. The contraction and the half-relaxation times were significantly longer in female MUs, what might be due to differences in muscle architecture. The force-frequency curve of slow MUs in males was shifted rightwards with respect to females, indicating that the same relative level of a tetanic force could be achieved at a considerably higher stimulation frequency in males. The maximum force-time area per pulse was significantly higher for males, and the analysis of MU action potentials revealed about four times higher amplitudes in male rats. In conclusion, numerous sex differences in MUs of the rat soleus muscle are not directly influenced by differences in body and muscle size.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2013
• Tom: 73
• Numer: Suppl.1
• Opis fizyczny: p.31

Twórcy

autor

Drzymala-Celichowska H.

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

autor

Krutki P.

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

autor

Celichowski J.

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