Author + information
- Received February 7, 1994
- Revision received May 12, 1994
- Accepted May 13, 1994
- Published online October 1, 1994.
- Yoshitaka Hirooka, MD,
- Kensuke Egashira, MD∗,
- Tsutomu Imaizumi, MD, FACC,
- Tatsuya Tagawa, MD,
- Hisashi Kai, MD,
- Masaru Sugimachi, MD and
- Akira Takeshita, MD, FACC
- ↵∗Address for correspondence: Dr. Kensuke Egashira, Research Institute of Angiocardiology and Cardiovascular Clinic, Kyushu University School of Medicine, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812, Japan.
Objectives. The goal of this study was to determine whether the elect of l-arginine on endothelium-dependent vasoditation evoked with acetylcholine differs between the coronary and forearm vasculatures in humans.
Background. Administration of l-arginine, a substrate in the production of endothetium-derived nitric oxide, may stimulate the release of nitric oxide.
Methods. Seven patients with normal coronary angiograms and seven with mild coronary artery disease and hypertension underwent coronary arteriography and an intracoronary Doppler catheter technique, and the diameter of the large epicardial coronary artery and coronary blood flow were measured. Forearm blood flow was measured by use of a strain gauge plethysmograph.
Results. Before l-arginine administration, acetylcholine (1 to 30 μg/min) increased coronary blood flow with modest vasoconstriction of a large coronary artery. Acetylcholine (4 to 24 μg/min) also increased forearm blood flow. The acetylcholine-induced increases in coronary and forearm blood flow were significantly less in patients with coronary artery disease than in control patients. Intracoronary infusion of l-arginine at 50 mg/min did not alter responses of the large coronary artery diameter or coronary blood flow to acetyicholine in either group. In contrast, l-arginine at 10 mg/min significantly (p < 0.01) augmented the forearm blood flow response to acetylcholine (4 to 24 μg/min) to a similar extent in the two groups.
Conclusions. The effect of l-arginine on acetylcholine-induced vasodilation difers between the coronary and forearm vasculatures in humans. It is suggested that impaired acetylcholine-induced coronary and forearm vasodilation in patients with coronary artery disease and hypertension may not be related to a limited availability of l-arginine.
☆ This study was supported by Grants-in-Aid for Scientific Research from the Japanese Ministry of Education, Science and Culture, Tokyo; a Research Development Award from the Naito Memorial Foundation, Tokyo; and a Research Grant from the Japan Heart Foundation, Tokyo, Japan.
- Received February 7, 1994.
- Revision received May 12, 1994.
- Accepted May 13, 1994.