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Titolo:
Fiber type and metabolic dependence of T2 increases in stimulated rat muscles
Autore:
Prior, BM; Ploutz-Snyder, LL; Cooper, TG; Meyer, RA;
Indirizzi:
Michigan State Univ, Dept Physiol, E Lansing, MI 48824 USA Michigan State Univ E Lansing MI USA 48824 ysiol, E Lansing, MI 48824 USA Michigan State Univ, Dept Radiol, E Lansing, MI 48824 USA Michigan State Univ E Lansing MI USA 48824 adiol, E Lansing, MI 48824 USA Syracuse Univ, Dept Exercise Sci, Syracuse, NY 13244 USA Syracuse Univ Syracuse NY USA 13244 Exercise Sci, Syracuse, NY 13244 USA
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 2, volume: 90, anno: 2001,
pagine: 615 - 623
SICI:
8750-7587(200102)90:2<615:FTAMDO>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
MAGNETIC-RESONANCE IMAGES; FAST-TWITCH MUSCLE; SKELETAL-MUSCLE; IN-VIVO; ELECTRICAL-STIMULATION; EXERCISE INTENSITY; IMAGING EVALUATION; T-2 RELAXATION; PH CHANGES; WORK;
Keywords:
magnetic resonance imaging; muscle functional magnetic resonance imaging; muscle recruitment; transverse relaxation time;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Meyer, RA Michigan State Univ, Dept Physiol, Giltner Hall, E Lansing, MI 48824 USA Michigan State Univ Giltner Hall E Lansing MI USA 48824 8824 USA
Citazione:
B.M. Prior et al., "Fiber type and metabolic dependence of T2 increases in stimulated rat muscles", J APP PHYSL, 90(2), 2001, pp. 615-623

Abstract

This study examined the relationships between muscle fiber type, metabolism, and blood flow vs. the increase in skeletal. muscle H-1-NMR transverse relaxation time (T2) after stimulation. Triceps surae muscles of anesthetized rats were stimulated in situ at 1-10 Hz for 6 min, and T2 was calculated from H-1-NMR images acquired at 4.7 T immediately after stimulation. At low-to-intermediate frequencies (1-5 Hz), the stimulation-induced T2 increase was greater in the superficial, fast-twitch white portion of the gastrocnemius muscle compared with the deeper, more aerobic muscles of the triceps surae group. Although whole triceps muscle area changed in parallel with T2 after stimulation when blood flow was intact, clamping of the femoral arteryduring stimulation prevented an increase in muscle area but not an increase in T2. Partial inhibition of lactic acid production with iodoacetate diminished intracellular acidification (measured by P-31-NMR spectroscopy) during brief (1.5 min) stimulation but had no significant effect either on estimated osmolite accumulation or on muscle T2 after stimulation. Depletion of muscle phosphocreatine content by feeding rats beta -guanidinopropionate decreased both estimated osmolite accumulation and T2 after 1.5-min stimulation. The results are consistent with the hypothesis that the T2 increase in stimulated muscle is related to osmotically driven shifts of fluid into an intracellular compartment.

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Documento generato il 06/04/20 alle ore 11:22:15