title: Interaction between muscle metaboreflex and mechanoreflex modulation of arterial baroreflex sensitivity in exercise.
abstract: The effect of external calf compression on baroreflex sensitivity (BRS) during electrically evoked plantar flexion and postexercise circulatory occlusion (PECO) was studied. Subjects took part in two experimental trials: control and compression. In both trials, electrically evoked isometric plantarflexion (Stim) was performed at 30% maximum voluntary contraction force for 2 min. During compression, a cuff (inflated to 250 mmHg) was applied to the active calf during exercise and PECO. Sequence analysis carried out on the systolic blood pressure responses, and R-wave-R-wave intervals revealed a rightward shift of the regression line along the pressure axis during Stim in both trials. In the control experiment, BRS was significantly (P < 0.01) increased from 10.37 +/- 1.87 ms/mmHg during Stim to 12.79 +/- 1.62 ms/mmHg during PECO. With external compression, BRS was unaltered between Stim (10.84 +/- 1.86 ms/mmHg) and PECO (11.40 +/- 1.54 ms/mmHg). Because the metabolic conditions were the same in both experiments, the results may best be explained by reactivation of muscle mechanoreceptor activity by external compression during PECO.
authors.affiliation: School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. C.A.Carrington@bham.ac.uk
authors.forename: C A
authors.initials: CA
authors.lastname: Carrington
authors.forename: C
authors.initials: C
authors.lastname: Ubolsakka
authors.forename: M J
authors.initials: MJ
authors.lastname: White
mesh_terms: D000328:Adult; D001158:Arteries / Q000502:physiology*; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D004558:Electric Stimulation; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism* / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology