Abnormal regional blood flow responses during and after exercise in human sympathetic denervation

Authors

  • Sharmini Puvi-Rajasingham,

    1. Neurovascular Medicine Unit, Department of Neuroendocrinology, Division of Neurosciences and Psychological Medicine, Imperial College School of Medicine at St Mary's Hospital, London and Autonomic Unit, University Department of Clinical Neurology, National Hospital for Neurology and Neurosurgery, Queen Square and Institute of Neurology, University College London, UK
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  • Gareth D. P. Smith,

    1. Neurovascular Medicine Unit, Department of Neuroendocrinology, Division of Neurosciences and Psychological Medicine, Imperial College School of Medicine at St Mary's Hospital, London and Autonomic Unit, University Department of Clinical Neurology, National Hospital for Neurology and Neurosurgery, Queen Square and Institute of Neurology, University College London, UK
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  • Adeola Akinola,

    1. Neurovascular Medicine Unit, Department of Neuroendocrinology, Division of Neurosciences and Psychological Medicine, Imperial College School of Medicine at St Mary's Hospital, London and Autonomic Unit, University Department of Clinical Neurology, National Hospital for Neurology and Neurosurgery, Queen Square and Institute of Neurology, University College London, UK
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  • Christopher J. Mathias

    Corresponding author
    1. Neurovascular Medicine Unit, Department of Neuroendocrinology, Division of Neurosciences and Psychological Medicine, Imperial College School of Medicine at St Mary's Hospital, London and Autonomic Unit, University Department of Clinical Neurology, National Hospital for Neurology and Neurosurgery, Queen Square and Institute of Neurology, University College London, UK
    • To whom correspondence should be addressed at the Neurovascular Medicine Unit, Imperial College School of Medicine, St Mary's Hospital, Praed Street, London W2 1NY, UK.

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Abstract

  • 2Blood pressure, superior mesenteric artery (SMA) and skeletal muscle blood flow, cardiac index (CI) and systemic vascular resistance responses to supine leg exercise were measured in six age-matched normal subjects (controls) and in eleven subjects with sympathetic denervation due to primary autonomic failure (AF).
  • 2During exercise, blood pressure rose in controls but fell markedly in AF. After exercise, blood pressure rapidly returned to baseline in controls but remained low in AF. During exercise, systemic vascular resistance fell in controls and AF but tended to fall further in AF and remained low post exercise. CI increased similarly in controls and AF.
  • 3During exercise, SMA blood flow fell similarly in controls and AF, but the fall initially was slower in AF; recovery was more rapid post exercise in controls. SMA vascular resistance tended to rise less and more slowly in AF and remained elevated post exercise.
  • 4Forearm muscle (FM) blood flow and FM vascular resistance did not change from resting values in controls or AF post exercise. After exercise, leg muscle (LM) blood flow rose and LM vascular resistance fell equally in both groups although LM blood flow remained elevated, 10 min post exercise in AF.
  • 5In sympathetically denervated humans, increased blood flow (due to excessive vasodilatation, lack of sympathetic restraint, or both) in leg muscle during and after exercise in combination with impaired splanchnic vasoconstriction in the early stages of exercise may have contributed to exercise-induced hypotension.

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