Estimation of blood flow by 133Xe clearance in human masseter muscle during rest, endurance of isometric contraction, and recovery.
Sixty-four measurements of 133Xe clearance from the masseters of 9 individuals, who had no facial or oral pain, were used to evaluate changes in intramuscular blood flow (IMBF) caused by endurance of isometric contraction at approx. 50 per cent of maximum voluntary EMG activity. On average, the IMBF during endurance increased by 4.2 times in 6 individuals and decreased 62 per cent of the rest flow in 3 individuals. Overall, the group average of endurance flow was 2.5 times higher than the initial rest flow. The group average of post-endurance hyperaemia was 27 times higher than the initial rest flow and 11 times higher than the endurance flow. IMBF during the final rest was 1.7 times higher than the initial rest flow. The relative IMBF during endurance was negatively correlated to muscle effort, and the post-endurance flow in relation to the endurance flow presented a compensatory positive correlation to the muscle effort. Although the average IMBF tended to increase during endurance, it was insufficient to meet the demand of the much higher relative increase in muscle activity, as indicated by the pronounced post-endurance hyperaemia, especially after long endurance.
Monteiro
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AA
Department of Stomatognathic Physiology, School of Dentistry, University of Lund, Malmö, Sweden.
Kopp
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D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008406:Masseter Muscle / Q000098:blood supply*; D008410:Masticatory Muscles / Q000098:blood supply*; D008954:Models, Biological; D009119:Muscle Contraction; D012039:Regional Blood Flow; D014980:Xenon Radioisotopes
D014980:Xenon Radioisotopes