EVIDENCE OF AN ADENOSINE‐DEPENDENT MECHANISM IN THE HYPOTENSIVE EFFECT OF l‐ARGININE IN MAN

Abstract

1. The hypothesis that endogenous adenosine could play a role in the haemodynamic response to L-arginine is investigated. 2. The study has been divided into two parts. The first part was a single blind, randomized, placebo-controlled study in which L-arginine i.v. infusion (0.07 mmol/kg per min) in five healthy volunteers caused a significant fall in systolic (-14.2%, from 129.0 +/- 8.2 to 110.6 +/- 8.5 mmHg; F = 62.89, P < 0.01), diastolic (-16%, from 80.0 +/- 7.9 to 67.2 +/- 7.0 mmHg; F = 18.97, P < 0.01) and mean (-15.5%, from 96.4 +/- 6.7 to 81.4 +/- 6.5 mmHg; F = 28.78, P < 0.01) arterial blood pressure, with a concomitant increase of plasma adenosine concentration (from 244.0 +/- 32.2 to 637.0 +/- 43.4 nmol/L; F = 79.3 P < 0.01). Maximal effects were obtained at the end of L-arginine infusion: haemodynamic parameters returned to basal values in about 30 min while adenosine concentrations normalized in about 15 min. Saline infusion had no effect on these parameters. 3. In the second study the effect of L-arginine i.v. infusion on arterial blood pressure, lower limb blood flow and plasma adenosine, before and after theophylline treatment (1000 mg/day for 3 days, p.o.) was examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of oral L-arginine supplementation on vasodilation and O2max in male soccer players

“…Many authors suggested that supplementation of arginine improved endothelial function in experimental animals and in humans. Intravenous administration of L-arginine improved vasodilation, blood pressure, blood flow and exercise capacity of healthy subjects [5,6,9,10,12,13,16,18,21]. Short-term oral administration of L-arginine also improved endothelium-dependent vasodilation of the brachial artery in a study of healthy elderly individuals [4].…”

“…In single-blinded, randomised and placebo-controlled studies on healthy volunteers , L-arginine infusion brought about a significant fall in systolic, diastolic and mean arterial pressures [16,18]. Moreover, Siani et al [28] showed that the intake of an L-arginine-enriched diet induced a reduction in arterial blood pressure in healthy volunteers.…”