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Nonselective beta‐blockade enhances pressor responsiveness to epinephrine, norepinephrine, and angiotensin II in normal man
Author(s) -
Reeves Richard A,
Boer Walther H,
DeLeve Laurie,
Leenen Frans H H
Publication year - 1984
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1984.60
Subject(s) - propranolol , epinephrine , norepinephrine , angiotensin ii , blockade , medicine , blood pressure , endocrinology , placebo , heart rate , dopamine , receptor , alternative medicine , pathology
Nonselective β‐blockers increase peripheral vascular resistance and, sometimes, blood pressure (BP); increased responsiveness to circulating pressor agents could be one of the underlying mechanisms. Heart rate (HR) and BP responses to graded intravenous infusions of epinephrine, norepinephrine, and angiotensin II were recorded after placebo and then after 4 wk of β‐blocker treatment (nadolol or propranolol, 240 mg/day) in 10 healthy young men. Adequacy of β‐blockade was demonstrated by a mean 31% decrease in HR response to bicycle exercise, with no differences between the two β‐blockers. Under placebo conditions epinephrine lowered diastolic BP and raised HR; these effects were reversed during treatment with β‐blockers. β‐Blockade potentiated BP responses to norepinephrine and angiotensin II: Thirty‐five percent less norepinephrine and 52% less angiotensin II were required to increase mean BP by 15 mm Hg. A final study 2 wk after β‐blocker cessation revealed the absence of lasting effect. These results confirm the concept of unopposed α‐constriction for epinephrine and also demonstrate increased BP responses to norepinephrine and angiotensin II during chronic β‐blockade. Clinical Pharmacology and Therapeutics (1984) 35, 461–466; doi: 10.1038/clpt.1984.60