Myles W O'Brien1, Beverly D Schwartz2, Jennifer L Petterson2, Derek S Kimmerly2. 1. Autonomic Cardiovascular Control and Exercise Laboratory, Division of Kinesiology, Faculty of Health, School of Health and Human Performance, Dalhousie University, 6230 South Street, Halifax, NS, B3H 4R2, Canada. myles.obrien@dal.ca. 2. Autonomic Cardiovascular Control and Exercise Laboratory, Division of Kinesiology, Faculty of Health, School of Health and Human Performance, Dalhousie University, 6230 South Street, Halifax, NS, B3H 4R2, Canada.
Abstract
PURPOSE: Spontaneous sympathetic transduction reflects the vascular and/or pressor responses to bursts of muscle sympathetic nerve activity (MSNA). Separately, signal-averaging and regression-based approaches have been implemented to quantify resting sympathetic transduction. It is unknown whether the outcomes of these analytical approaches provide (dis)similar information, which is imperative for between-study comparisons and the amalgamation of results for synthesis of multiple studies (i.e., meta-analyses). We explored the diastolic blood pressure (DBP) responses to spontaneous bursts of MSNA between these two methods of analysis. METHODS: Resting beat-by-beat DBP (via finger photoplethysmography) and common peroneal nerve MSNA (via microneurography) were recorded in 52 healthy, normotensive adults (age 38 ± 20 years; 19 females). For the signal-averaged method, transduction was quantified as the mean peak increase in DBP (ΔDBP) during the 12 cardiac cycles following each MSNA burst. In addition, DBP was regressed to a moving two-cardiac-cycle window of normalized relative burst height (mmHg/relative %) to provide the regression-based transduction outcome. RESULTS: The signal-averaged (1.2 ± 0.7 mmHg) and regression-based approaches (0.009 ± 0.016 mmHg/%) were unrelated (ρ = 0.03, p = 0.86). Adding to the discrepancy, only the signal-averaging approach demonstrated a lower transduction in middle-aged-older males versus younger males. CONCLUSIONS: The decision of which method to use when calculating sympathetic transduction influences study outcomes, with the two most common methods of determining transduction being unrelated. There are challenges of making sweeping conclusions across studies if different analysis strategies are implemented. An understanding of when to use each method is needed to adopt a harmonized approach to quantifying sympathetic transduction.
PURPOSE: Spontaneous sympathetic transduction reflects the vascular and/or pressor responses to bursts of muscle sympathetic nerve activity (MSNA). Separately, signal-averaging and regression-based approaches have been implemented to quantify resting sympathetic transduction. It is unknown whether the outcomes of these analytical approaches provide (dis)similar information, which is imperative for between-study comparisons and the amalgamation of results for synthesis of multiple studies (i.e., meta-analyses). We explored the diastolic blood pressure (DBP) responses to spontaneous bursts of MSNA between these two methods of analysis. METHODS: Resting beat-by-beat DBP (via finger photoplethysmography) and common peroneal nerve MSNA (via microneurography) were recorded in 52 healthy, normotensive adults (age 38 ± 20 years; 19 females). For the signal-averaged method, transduction was quantified as the mean peak increase in DBP (ΔDBP) during the 12 cardiac cycles following each MSNA burst. In addition, DBP was regressed to a moving two-cardiac-cycle window of normalized relative burst height (mmHg/relative %) to provide the regression-based transduction outcome. RESULTS: The signal-averaged (1.2 ± 0.7 mmHg) and regression-based approaches (0.009 ± 0.016 mmHg/%) were unrelated (ρ = 0.03, p = 0.86). Adding to the discrepancy, only the signal-averaging approach demonstrated a lower transduction in middle-aged-older males versus younger males. CONCLUSIONS: The decision of which method to use when calculating sympathetic transduction influences study outcomes, with the two most common methods of determining transduction being unrelated. There are challenges of making sweeping conclusions across studies if different analysis strategies are implemented. An understanding of when to use each method is needed to adopt a harmonized approach to quantifying sympathetic transduction.
Authors: Seth T Fairfax; Seth W Holwerda; Daniel P Credeur; Mozow Y Zuidema; John H Medley; Peter C Dyke; D Walter Wray; Michael J Davis; Paul J Fadel Journal: J Physiol Date: 2013-05-07 Impact factor: 5.182
Authors: Massimo Nardone; Anthony V Incognito; André L Teixeira; Joseph A Cacoilo; Lauro C Vianna; Philip J Millar Journal: Appl Physiol Nutr Metab Date: 2021-01-11 Impact factor: 2.665
Authors: Myles W O'Brien; Diane J Ramsay; Carley D O'Neill; Jennifer L Petterson; Shilpa Dogra; Said Mekary; Derek S Kimmerly Journal: Geroscience Date: 2021-05-31 Impact factor: 7.713
Authors: Matthew D Kobetic; Amy E Burchell; Laura E K Ratcliffe; Sandra Neumann; Zoe H Adams; Regina Nolan; Angus K Nightingale; Julian F R Paton; Emma C Hart Journal: J Hum Hypertens Date: 2021-08-27 Impact factor: 3.012
Authors: L J B Briant; A E Burchell; L E K Ratcliffe; N Charkoudian; A K Nightingale; J F R Paton; Michael J Joyner; E C Hart Journal: J Physiol Date: 2016-07-03 Impact factor: 5.182