title: Comparison of 133Xe clearance and laser Doppler flowmetry in assessment of blood flow changes in human masseter muscle induced by isometric contraction.
abstract: Changes induced by 30 s of isometric contraction at 10% and 50% of the maximum voluntary contraction were assessed in 10 healthy subjects; there was a median increase of 1.8 and 0.3 times in 133Xe clearance and 5.3 and 2.7 times in laser Doppler flowmetry. In the first minute after 10% maximum voluntary contraction, 133Xe clearance increased 12.1 times in relation to the initial resting level, and flowmetry values decreased to become 3.5 times higher than the basal flow; corresponding values after 50% maximum voluntary contraction were 24.3 times and 3.7 times. From the second minute after contraction, there was a rapid decrease in 133Xe clearance and a slow decrease in flowmetry values. Five minutes after biting at 10% maximum voluntary contraction, both methods showed a total net increase of about 15 times; after biting at 50% maximum voluntary contraction the corresponding values were 38 and 23 times. Thus laser Doppler flowmetry can be used to assess changes in blood flow in the masseter; it registers a greater increase in flow during isometric contraction than does 133Xe clearance. The significant difference between methods immediately after either chosen level of contraction disappears when the total net post-contraction hyperaemia is assessed over a period of 2 and 5 min, respectively.
authors.affiliation: Department of Clinical Oral Physiology, School of Dentistry, Karolinska Institutet, Huddinge, Sweden.
authors.forename: A A
authors.initials: AA
authors.lastname: Monteiro
authors.forename: H
authors.initials: H
authors.lastname: Svensson
authors.forename: S
authors.initials: S
authors.lastname: Bornmyr
authors.forename: M
authors.initials: M
authors.lastname: Arborelius
authors.forename: S
authors.initials: S
authors.lastname: Kopp
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D007834:Lasers; D008297:Male; D008406:Masseter Muscle / Q000098:blood supply*; D008410:Masticatory Muscles / Q000098:blood supply*; D009119:Muscle Contraction / Q000502:physiology*; D012039:Regional Blood Flow; D014980:Xenon Radioisotopes
chemical_list: D014980:Xenon Radioisotopes