B von zur Můhlen1, J Millgård, L Lind. 1. Department of Internal Medicine, University Hospital of Uppsala, Sweden. bengt.muhlen@medsci.uu.se
Abstract
OBJECTIVE: The aim of this study was to evaluate the direct effect of three principally different beta-receptor blocking agents on endothelium-dependent vasodilatation (EDV) in the human forearm. METHODS: In 27 young normotensive subjects forearm blood flow (FBF) was measured with venous occlusion plethysmography during local intra-arterial infusions of methacholine (MCh), evaluating EDV, and sodium nitroprusside (SNP), evaluating endothelium-independent vasodilatation (EIDV). The measurements of EDV and EIDV were undertaken at baseline conditions and repeated after 1 h of concomitant intra-arterial infusion of atenolol (n = 8, 1.2 mg/h), propranolol (n = 7, 1.2 mg/h), labetalol (n = 7, 16 mg/h) or saline (n = 5). RESULTS: The selective beta-blocker atenolol showed a tendency to improve the FBF response to MCh (from 28.8 +/- 9.2 to 32.6 +/- 8.7 ml/min/ml tissue, p < 0.05). The nonselective beta-blocker propranolol attenuated the FBF response to MCh significantly (from 30.5 +/- 6.7 to 22.8 +/- 4.5 ml/min/ml tissue, p < 0.01). In these groups baseline FBF and EIDV were unchanged. Labetalol, a combined non-selective beta-blocker and selective alpha-1-blocker, increased baseline FBF and increased the response to both MCh and SNP in parallel (p < 0.05 for MCh and p = 0.07 for SNP). Saline did not change baseline FBF, EDV or EIDV. CONCLUSIONS: This study showed that local infusion of different beta-blocking agents in normotensive subjects affects endothelial vasodilatory function differently. This technique could be used to evaluate the direct effect of vasoactive drugs on EDV.
OBJECTIVE: The aim of this study was to evaluate the direct effect of three principally different beta-receptor blocking agents on endothelium-dependent vasodilatation (EDV) in the human forearm. METHODS: In 27 young normotensive subjects forearm blood flow (FBF) was measured with venous occlusion plethysmography during local intra-arterial infusions of methacholine (MCh), evaluating EDV, and sodium nitroprusside (SNP), evaluating endothelium-independent vasodilatation (EIDV). The measurements of EDV and EIDV were undertaken at baseline conditions and repeated after 1 h of concomitant intra-arterial infusion of atenolol (n = 8, 1.2 mg/h), propranolol (n = 7, 1.2 mg/h), labetalol (n = 7, 16 mg/h) or saline (n = 5). RESULTS: The selective beta-blocker atenolol showed a tendency to improve the FBF response to MCh (from 28.8 +/- 9.2 to 32.6 +/- 8.7 ml/min/ml tissue, p < 0.05). The nonselective beta-blocker propranolol attenuated the FBF response to MCh significantly (from 30.5 +/- 6.7 to 22.8 +/- 4.5 ml/min/ml tissue, p < 0.01). In these groups baseline FBF and EIDV were unchanged. Labetalol, a combined non-selective beta-blocker and selective alpha-1-blocker, increased baseline FBF and increased the response to both MCh and SNP in parallel (p < 0.05 for MCh and p = 0.07 for SNP). Saline did not change baseline FBF, EDV or EIDV. CONCLUSIONS: This study showed that local infusion of different beta-blocking agents in normotensive subjects affects endothelial vasodilatory function differently. This technique could be used to evaluate the direct effect of vasoactive drugs on EDV.
Authors: Britt Kveiborg; Thomas S Hermann; Atheline Major-Pedersen; Buris Christiansen; Christian Rask-Madsen; Jakob Raunsø; Lars Køber; Christian Torp-Pedersen; Helena Dominguez Journal: Cardiovasc Diabetol Date: 2010-05-25 Impact factor: 9.951
Authors: J Richard Jennings; Matthew F Muldoon; Julie Price; Israel C Christie; Carolyn C Meltzer Journal: Hypertension Date: 2008-06-02 Impact factor: 10.190