Sympathetic Activation Does Not Affect the Cardiac and Respiratory Contribution to the Relationship between Blood Pressure and Pial Artery Pulsation Oscillations in Healthy Subjects

PLoS One. 2015 Aug 18;10(8):e0135751. doi: 10.1371/journal.pone.0135751. eCollection 2015.


Introduction: Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects.

Methods: The pial artery and subarachnoid width response to handgrip (HGT) and cold test (CT) were studied in 20 healthy subjects. The cc-TQ and sas-TQ were measured using NIR-T/BSS; cerebral blood flow velocity (CBFV) was measured using Doppler ultrasound of the left internal carotid artery; heart rate (HR) and beat-to-beat mean BP were recorded using a continuous finger-pulse photoplethysmography; respiratory rate (RR), minute ventilation (MV), end-tidal CO2 (EtCO2) and end-tidal O2 (EtO2) were measured using a metabolic and spirometry module of the medical monitoring system. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations.

Results: HGT evoked an increase in BP (+15.9%; P<0.001), HR (14.7; P<0.001), SaO2 (+0.5; P<0.001) EtO2 (+2.1; P<0.05) RR (+9.2%; P = 0.05) and MV (+15.5%; P<0.001), while sas-TQ was diminished (-8.12%; P<0.001), and a clear trend toward cc-TQ decline was observed (-11.0%; NS). CBFV (+2.9%; NS) and EtCO2 (-0.7; NS) did not change during HGT. CT evoked an increase in BP (+7.4%; P<0.001), sas-TQ (+3.5%; P<0.05) and SaO2(+0.3%; P<0.05). HR (+2.3%; NS), CBFV (+2.0%; NS), EtO2 (-0.7%; NS) and EtCO2 (+0.9%; NS) remained unchanged. A trend toward decreased cc-TQ was observed (-5.1%; NS). The sas-TQ response was biphasic with elevation during the first 40 seconds (+8.8% vs. baseline; P<0.001) and subsequent decline (+4.1% vs. baseline; P<0.05). No change with respect to wavelet coherence and wavelet phase coherence was found between the BP and cc-TQ oscillations.

Conclusions: Short sympathetic activation does not affect the cardiac and respiratory contribution to the relationship between BP-cc-TQ oscillations. HGT and CT display divergent effects on the width of the subarachnoid space, an indirect marker of changes in intracranial pressure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arteries / physiology*
  • Blood Pressure / physiology*
  • Carbon Dioxide / metabolism
  • Female
  • Healthy Volunteers*
  • Heart / physiology*
  • Heart Rate / physiology
  • Humans
  • Male
  • Oxygen / metabolism
  • Pulmonary Ventilation / physiology
  • Pulsatile Flow / physiology*
  • Respiration*
  • Sympathetic Nervous System / physiology*


  • Carbon Dioxide
  • Oxygen

Grant support

The study was conducted as a part of the PHYPODE Marie Curie Initial Training Networks (FP7-PEOPLE-2010-ITN) and received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FRP/2007-2013/ under the Research Executive Agency grant agreement [grant number 264816]. Funding came also from the Medical University of Gdansk and NIRT sp. z o. o., Wierzbice, Poland. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.