The effect of age on in vitro motility speed of slow myosin extracted from single rat soleus fibres.
The effect of age on the motor protein myosin was examined in a novel in vitro motility assay. Myosin was extracted from soleus fibres of young (3-6 month) and old (20-24 month) rats. All fibres expressed the type I myosin heavy chain (MyHC) and the slow isoforms of the myosin light chains (MyLCs). In vitro motility speed was significantly (P < 0.001) faster in the young adult (1.43 +/- 0.23 microm s-1) than in the aged group (1.27 +/- 0.23 microm s-1). The result indicates that the age-related decrease in contractile speed observed in slow fibres may be the effect of a change in the properties of myosin with age.
Höök
P
P
Noll Physiological Research Center, the Pennsylvania State University, PA 16802, USA.
Li
X
X
Sleep
J
J
Hughes
S
S
Larsson
L
L
D000375:Aging / Q000502:physiology*; D000818:Animals; D066298:In Vitro Techniques; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000502:physiology*; D018994:Myosin Light Chains / Q000502:physiology*; D051381:Rats
D018994:Myosin Light Chains; D018995:Myosin Heavy Chains