P-210: Beta-blockade with nebivolol enhances the acetylcholine-induced vasodilation in the cutaneaous vascular bed of normotensive volunteers

Abstract

This study was undertaken to assess whether the beta1-adrenoceptor blocker nebivolol(N) increases the vasodilatory response to acetylcholine(Ach) when administered orally to healthy subjects. To this end 12 volunteers were randomly allocated to a 8-day treatment with nebivolol (n), 5 mg once a day, and atenolol(A),50 mg once a day, according to a cross-over design, with a 1 week wash-out period between the two treatment phases. The forearm skin blood flow(SBF) response to Ach applied by iontophoresis was determined using a laser-Doppler scanner imaging system before(T0) and 3 hours(T3) after N or A dosing, both on the first (Day 1) and the last day (Day 8) of treatment. The following Table shows the responses of SBF (perfusion units) (means±SD; *p<0.05 versus T0):

	Day 1		Day 8
	T0	T3	T0	T3
Nebivolol	98±93	441±109*	393±110	426±105*
Atenolol	396±97	410±99	380±109	394±98

Iontophoresis of 0.09% NaCl had no effect on SBF. These data indicate that nebivolol (administered at a dose commonly used in clinical practice), but not atenolol, enhances in humans the vasorelaxant activity of Ach in the skin vascular bed, which is compatible with a facilitation by this beta-blocker of the endothelium-dependent vasodilation.

Beta-adrenoceptor blockade, Endothelial function, Skin microcirculation

© American Journal of Hypertension, Ltd. 2001