Agein affect the rate of force development of motor units in rat fast muscle

• Autorzy: Kaczmarek D. , Lochynski D. , Celichowski J. , Krutki P.
• Języki publikacji: EN

Abstrakty

EN

The rate of force development (RFD) of skeletal muscle decreases with ageing. The purpose of this study was to determine whether this phenomenon may be connected with the age-related changes in motor unit (MU) properties. One group of young (5–10 months old, n=9) and two groups of old (24–25 months old, n=6 and 28–30 months old, n=8) male Wistar rats were studied. Contractile activity of isolated MUs in the rat medial gastrocnemius muscle was evoked by electrical stimulation of ventral root fi laments. MUs were classifi ed into fast fatigable (FF), fast resistant (FR), and slow (S) according to susceptibility to fatigue and twitch contraction time. The RFD, force and force-time integral (FTI) of twitch, contraction following doublet pulse stimulation and maximal tetanus were measured and compared. Absolute and relative RFD of studied MUs evidently increased with ageing. We observed gradual augmentation of absolute force and FTI of evoked doublet contractions during ageing in S MUs while in FF units this increase was transient (only for 24–25 months old animals). However, the relative values of force and FTI after doublet stimulus were lower in S and FR MUs and unchanged in FF units in old animals as compared to the young. The increase in MU RFD is opposite to decrease in muscle RFD with ageing. The decline of the muscle performance capabilities can not be attributed to deterioration of mechanical parameters of survived MUs but rather is due to overall loss and change in proportion of MUs.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2009
• Tom: 69
• Numer: 3
• Opis fizyczny: p.328

Twórcy

autor

Kaczmarek D.

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

autor

Lochynski D.

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

autor

Celichowski J.

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

autor

Krutki P.

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