| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Departments of 1 Physiology and 3 Radiology, Michigan State University, East Lansing, Michigan 48824; and 2 Department of Exercise Science, Syracuse University, Syracuse, New York 13244
This study examined the relationships between muscle
fiber type, metabolism, and blood flow vs. the increase in skeletal muscle 1H-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
1H-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 artery during 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 31P-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 
-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.
magnetic resonance imaging; muscle functional magnetic resonance imaging; muscle recruitment; transverse relaxation time
This article has been cited by other articles:
|
|
 |
|
  T. Marqueste, B. Giannesini, Y. L. Fur, P. J. Cozzone, and D. Bendahan Comparative MRI analysis of T2 changes associated with single and repeated bouts of downhill running leading to eccentric-induced muscle damage J Appl Physiol, July 1, 2008; 105(1): 299 - 307. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. L Segal Use of Imaging to Assess Normal and Adaptive Muscle Function Physical Therapy, June 1, 2007; 87(6): 704 - 718. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Kinugasa, Y. Kawakami, and T. Fukunaga Muscle activation and its distribution within human triceps surae muscles J Appl Physiol, September 1, 2005; 99(3): 1149 - 1156. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. M. Damon and J. C. Gore Physiological basis of muscle functional MRI: predictions using a computer model J Appl Physiol, January 1, 2005; 98(1): 264 - 273. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Duteil, C. Bourrilhon, J. S. Raynaud, C. Wary, R. S. Richardson, A. Leroy-Willig, J. C. Jouanin, C. Y. Guezennec, and P. G. Carlier Metabolic and vascular support for the role of myoglobin in humans: a multiparametric NMR study Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2004; 287(6): R1441 - R1449. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. M. Damon, D. M. Wigmore, Z. Ding, J. C. Gore, and J. A. Kent-Braun Cluster analysis of muscle functional MRI data J Appl Physiol, September 1, 2003; 95(3): 1287 - 1296. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Akima, J. M. Foley, B. M. Prior, G. A. Dudley, and R. A. Meyer Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans J Appl Physiol, February 1, 2002; 92(2): 679 - 684. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
