Effect of beta-adrenergic stimulation on pulse wave velocity in black and white subjects.
BACKGROUND
Reduced beta-adrenergic sensitivity has been reported in black subjects. We hypothesized that beta-adrenergic stimulation by isoproterenol would affect pulse wave velocity (PWV), a marker of arterial stiffness, differently in black and white subjects.


METHODS
Healthy normotensive black subjects (n = 21) matched for age, gender, height and body mass index with healthy normotensive white subjects (n = 20), participated in a randomized, double-blind, placebo-controlled cross-over study. The PWV was determined using an automated device at baseline and after 30 min of an equal volume infusion of isoproterenol (8 mug/kg per min) or placebo (dextrose 5%), separated by a washout period of 25 min.


RESULTS
At baseline, heart rate (HR), systolic and diastolic blood pressure (SBP, DBP) and PWV were comparable in black and in white subjects. Placebo had no significant effect on haemodynamic variables. Isoproterenol increased HR, SBP and pulse pressure and decreased DBP with a comparable magnitude in both groups. Compared with placebo, isoproterenol decreased carotid-femoral PWV in white (from 5.9 +/- 1.2 to 5.7 +/- 1.1 m/s, means +/- SD, P = 0.05), but not in black subjects (from 6.2 +/- 1.3 to 6.6 +/- 1.7 m/s, P = 0.1). The difference in response between black and white subjects was significant (P = 0.04). Isoproterenol decreased carotid-radial PWV only significantly in white subjects.


CONCLUSIONS
These results are compatible with the hypothesis of an altered beta-adrenergic sensitivity, which is expressed by a blunted effect of isoproterenol on arterial stiffness in black subjects.
Lemogoum
Daniel
D
Hypertension Clinic, Department of Cardiology, Erasme University Hospital, Brussels, Belgium.
Van Bortel
Luc
L
Van den Abeele
Wouter
W
Ciarka
Agneska
A
Degaute
Jean-Paul
JP
van de Borne
Philippe
P
Leeman
Marc
M
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000328:Adult; D044383:Black People; D001783:Blood Flow Velocity / Q000187:drug effects*; D002339:Carotid Arteries / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005263:Femoral Artery / Q000187:drug effects; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D011674:Pulse; D015203:Reproducibility of Results; D044465:White People
D000318:Adrenergic beta-Agonists; D007545:Isoproterenol