Abnormal norepinephrine clearance and adrenergic receptor sensitivity in idiopathic orthostatic intolerance

Giris Jacob, John R. Shannon, Fernando Costa, Raffaello Furlan, Italo Biaggioni, Rogelio Mosqueda-Garcia, Rose Marie Robertson, David Robertson

Research output: Contribution to journalArticle

Abstract

Background-Chronic orthostatic intolerance (OI) is characterized by symptoms of inadequate cerebral perfusion with standing, in the absence of significant orthostatic hypotension. A heart rate increase of ≥30 bpm is typical. Possible underlying pathophysiologies include hypovolemia, partial dysautonomia, or a primary hyperadrenergic state. We tested the hypothesis that patients with OI have functional abnormalities in autonomic neurons regulating cardiovascular responses. Methods and Results-Thirteen patients with chronic OI and 10 control subjects underwent a battery of autonomic tests. Systemic norepinephrine (NE) kinetics were determined with the patients supine and standing before and after tyramine administration. In addition, baroreflex sensitivity, hemodynamic responses to bolus injections of adrenergic agonists, and intrinsic heart rate were determined. Resting supine NE spillover and clearance were similar in both groups. With standing, patients had a greater decrease in NE clearance than control subjects (55±5% versus 30±7%, P

Original languageEnglish
Pages (from-to)1706-1712
Number of pages7
JournalCirculation
Volume99
Issue number13
Publication statusPublished - Apr 6 1999

    Fingerprint

Keywords

  • Nervous system, autonomic
  • Norepinephrine
  • Receptors, adrenergic, alpha
  • Receptors, adrenergic, beta

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Jacob, G., Shannon, J. R., Costa, F., Furlan, R., Biaggioni, I., Mosqueda-Garcia, R., Robertson, R. M., & Robertson, D. (1999). Abnormal norepinephrine clearance and adrenergic receptor sensitivity in idiopathic orthostatic intolerance. Circulation, 99(13), 1706-1712.