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Vasomodulation of skeletal muscle BOLD signal
Author(s) -
Bulte Daniel P.,
Alfonsi Jeff,
Bells Sonya,
Noseworthy Michael D.
Publication year - 2006
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20690
Subject(s) - caffeine , soleus muscle , electrical impedance myography , skeletal muscle , sarcopenia , medicine , endocrinology , chemistry , contractility , gastrocnemius muscle , anatomy , vasodilation
Purpose To evaluate whether the BOLD signal from skeletal muscle can be modulated by exercise and ingestion of vasoactive substances. Materials and Methods The right calf muscles of healthy adult volunteers were imaged using a GE 1.5‐Tesla scanner and a gradient‐echo sequence with spiral readout. Time‐varying changes in the BOLD signal were induced through cyclic phases of normoxia (90 seconds of 20.8% O 2 ) and hyperoxia (45 seconds of 100% O 2 at 22 L/minute). Superimposed on this paradigm were pre‐ and post‐exercise regimes, with and without ingestion of caffeine (100 mg) or antihistamine (4 mg chlorpheniramine). The numbers of voxels within slow‐twitch (soleus) and fast‐twitch (gastrocnemius) muscles that significantly responded to the paradigms were scored and compared using the AFNI software (NIMH). Results Cycling‐inspired O 2 produced a corresponding BOLD modulation that increased in magnitude with exercise. Chlorpheniramine significantly ( P < 0.01) prevented the overall increase in exercise‐induced soleus muscle BOLD signal, while caffeine accentuated the increase ( P < 0.05) in the gastrocnemius relative to control (no vasomodulator) conditions. Conclusion BOLD signal changes with exercise can be modulated by standard doses of chlorpheniramine (antihis‐tamine) and caffeine. We suggest that chlorpheniramine may act detrimentally on slow‐twitch muscle contractility, while caffeine appears to improve fast‐twitch muscle function. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.