title: Slowing of contractile properties in quail skeletal muscle with aging.
abstract: The effect of aging on muscle contractile function was examined in the anterior latissimus dorsi (ALD) muscle of Japanese quails aged 8 weeks (young adults), 26 weeks, 60 weeks, or 90 weeks (old birds). In vitro contractile measures of the ALD were made at 25 degrees C (stimulus pulse = 0.1 ms). Twitch contraction time in 90-week-old muscles was significantly greater than 8 to 26-week-old muscles (150 +/- 8 ms vs 168 +/- 18 ms). Similarly, one-half relaxation time of the twitch was increased in the ALD from old birds (221 +/- 17 ms) relative to adult birds 8-26 weeks (173 +/- 11). Aging produced a greater fusing of twitches at stimulation frequencies of 5 and 10 Hz, and this resulted in a leftward shift of the force-frequency curve at these frequencies. Shortening velocity measured by the force-velocity method (Vmax) decreased from 2.6 +/- 0.2 muscle length/s (mL/s) to 1.19 +/- 0.02 mL/s in 8 and 90-week-old muscles, respectively. Maximal velocity of unloaded shortening as measured by the slack test decreased from 3.6 +/- 0.7 mL/s to 2.4 mL/s in 8-week-old and 90-week-old muscles, respectively. Maximal tetanic force (60.6 +/- 3.1 mN) and specific force (11.3 +/- 0.3 N/cm2) were similar in young adult and old muscles. These data indicate that aging induces a slowing of both twitch contractile characteristics and shortening velocity in the ALD, without affecting maximal force capabilities.
authors: Department of Exercise Science, Ohio State University.
authors: S E
authors: SE
authors: Alway
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D003370:Coturnix; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*