Korean J Intern Med.  2002 Jun;17(2):131-137.

Improvement of Endothelial Function by Amlodipine and Vitamin C in Essential Hypertension

• On YK
• Kim CH
• Sohn DW
• Oh BH
• Lee MM
• Park YB
• Choi YS

Abstract

BACKGROUND: The effects of antihypertensive agents on endothelial function have not been fully evaluated in human hypertension and data on the forearm circulation of humans are controversial. The aim of this study was (1) to evaluate the endothelial function in hypertensive patients (2) to investigate whether vitamin C administration has any benefit on the endothelial function and (3) to determine whether treatment with calcium antagonist improves endothelial dysfunction in hypertensive patients.
METHODS
The endothelial function was estimated using venous occlusion plethysmography (VOP) in 8 hypertensive patients and 8 healthy volunteers. The patients in the hypertension group were treated with amlodipine, then examined again. The change of forearm blood flow (FBF) was measured with acetylcholine infusion through brachial artery and also with intra-arterial vitamin C.
RESULTS
Forearm blood flow response to acetylcholine was significantly enhanced with intra-arterial infusion of vitamin C in hypertensive group before antihypertensive treatment. Co-infusion of L-NMMA, an inhibitor of nitric oxide synthase, blunted forearm blood flow response to acetylcholine. After treatment with amlodipine for 2 months in hypertensive group, endothelium-dependent vasorelaxation to acetylcholine was significantly improved compared to pretreatment, and vitamin C did not affect the improved endothelial function by amlodipine treatment.
CONCLUSION
Vitamin C (acutely) and amlodipine (chronically) improved endothelial function in hypertensive patients. These results suggest that increased oxidative stress, at least in part, may be involved in the decreased endothelial function in hypertension.

Keyword

Plethysmography; Endothelium; Hypertension; Ascorbic acid; Amlodipine

MeSH Terms

Adult
Aged
Amlodipine/*therapeutic use
Antihypertensive Agents/therapeutic use
Ascorbic Acid/*therapeutic use
Calcium Channel Blockers/therapeutic use
Endothelium, Vascular/*drug effects/*physiopathology
Enzyme Inhibitors/pharmacology
Female
Human
Hypertension/*drug therapy/*physiopathology
Male
Middle Age
Nitric-Oxide Synthase/antagonists & inhibitors
Vasodilation/drug effects
omega-N-Methylarginine/pharmacology