This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Stein, C. M. Articles by Wood, A. J. J. Search for Related Content PubMed PubMed Citation Articles by Stein, C. M. Articles by Wood, A. J. J.

(Hypertension. 1998;32:1016-1021.)
© 1998 American Heart Association, Inc.

Scientific Contributions

Basal and Stimulated Sympathetic Responses After Epinephrine

No Evidence of Augmented Responses

C. Michael Stein; Huai B. He; Alastair J. J. Wood

From the Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, Tenn.

Correspondence to Dr C. Michael Stein, Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Medical Research Building 1, Room 560, Nashville, TN 37232-6602. E-mail michael.stein{at}mcmail.vanderbilt.edu

Abstract—Delayed facilitation of norepinephrine release through the action of epinephrine (NE) at presynaptic ß-adrenoceptors has been postulated to account for the delayed hemodynamic effects of epinephrine and to be a mechanism causally related to the development of hypertension. To determine whether a short-term increase in epinephrine concentrations resulted in subsequent facilitation of sympathetic responses, 9 healthy subjects (age, 21±0.9 years) were studied at rest and during physiological stress on 2 occasions when they received an infusion of either saline or epinephrine (20 ng/kg per minute) in random order. Heart rate, blood pressure, forearm blood flow, epinephrine concentrations, and NE spillover were measured at rest, during mental stress (Stroop test), and during a cold pressor test. Measurements were performed before, during the 1-hour infusion of epinephrine or placebo, and 1 hour after the infusion. A radioisotope dilution method was used to measure NE spillover. Hemodynamic measurements and NE spillover were increased during the infusion of epinephrine, but 1 hour after discontinuation of epinephrine there was no significant augmentation of hemodynamic or sympathetic responses. NE spillover 1 hour after saline or epinephrine infusion was similar (0.85±0.2 versus 0.87±0.2 µg/min; P=0.92). In addition, there was no delayed facilitation of stress-induced hemodynamic or NE responses after epinephrine. These findings do not support the hypothesis that epinephrine results in delayed facilitation of NE release.

Key Words: epinephrine • norepinephrine • sympathetic nervous system • stress