title: Plasma norepinephrine, blood pressure and heart rate response to graded change in body position.
abstract: In this study, 44 human subjects underwent either an orthostatic postural change (supine to stand, n = 17) or a graded change in body position (head-up) on a tilt-table (n = 27). No significant changes in systolic blood pressure or mean blood pressure were observed during either maneuver; significant increases, under both conditions, were observed in diastolic blood pressure and heart rate. Plasma norepinephrine concentrations after orthostatic position change increased significantly (supine 181 +/- 14 (S.E.M.) pg X ml-1; stand, 472 +/- 35 pg X ml-1, p less than 0.01). Plasma norepinephrine concentrations during graded postural change increased proportionately with increasing degrees of tilt (r = 0.76, p less than 0.01). A significant correlation between plasma norepinephrine and heart rate was observed during both positional change maneuvers (graded tilt-table, r = 0.80, p less than 0.01; orthostatic, r = 0.50, p less than 0.01). These results suggest that the degree of sympathetic nervous system activity for blood pressure regulation during graded postural change is appropriately reflected by plasma norepinephrine concentrations.
mesh_terms: D000328:Adult; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000097:blood*; D011187:Posture; D013564:Sympathetic Nervous System / Q000502:physiology
chemical_list: D009638:Norepinephrine