N.O study

[The_KM]

Interesting study I stumbled upon.

No effect of short-term arginine supplementation on nitric oxide production, metabolism and performance in intermittent exercise in athletes.

Liu TH, Wu CL, Chiang CW, Lo YW, Tseng HF, Chang CK.

Department of Physical Education, Taiwan Sport University, 404 Taichung, Taiwan.

Arginine supplementation has been shown to alleviate endothelial dysfunction and improve exercise performance through increasing nitric oxide production in patients with cardiopulmonary diseases. In addition, arginine supplementation could decrease accumulations of lactate and ammonia, metabolites involved in development of muscular fatigue. The aim of this study was to investigate the effect of short-term arginine supplementation on performance in intermittent anaerobic exercise and the underlying mechanism in well-trained male athletes. Ten elite male college judo athletes participated with a randomized crossover, placebo-controlled design. The subjects consumed 6 g/day arginine (ARG trial) or placebo (CON trial) for 3 days then performed an intermittent anaerobic exercise test on a cycle ergometer. Blood samples were collected before supplementation, before and during exercise and 0, 3, 6, 10, 30 and 60 min after exercise. ARG trial had significantly higher arginine concentrations than CON trial at the same time point before, during and after exercise. In both trials, nitrate and nitrite concentration was significantly higher during and 6 min after exercise comparing to the basal concentration. The increase in nitrate and nitrite concentration during exercise in both trials was parallel to the increase in plasma citrulline concentrations. There was no significant difference between the 2 trials in plasma nitrate and nitrite, lactate and ammonia concentrations and peak and average power in the exercise. The results of this study suggested that short-term arginine supplementation had no effect on nitric oxide production, lactate and ammonia metabolism and performance in intermittent anaerobic exercise in well-trained male athletes.

Not sure this has any significance, but just thought it'd spark discussion. Thoughts anyone? It's funny because, NO is usually one of the first supplements advised of cycling and receptor tolerance.

Kev

 

[Bhana]

Well the study was only 3 days long lol, you think effects could be psychological?

 

[Adam23]

^^^i agree with you, 3 days is not long enough. i think a 4 to 6 weeks study would be better.

 

[cuts]

^^^i agree with you, 3 days is not long enough. i think a 4 to 6 weeks study would be better.

x3

 

[tim290280]

I've read similar studies but can't remember how long they were run for. I was under the impression that NO supplements weren't worth it.

But I agree that 3 days is a short observation period, most creatine trials are several weeks. But you do see physiological responses in the blood within a few hours with creatine, so why aren't you in NO supplements?

 

[The_KM]

Agree'd, it's short, yet still odd.

If arginine levels are high in the blood (endothelium), it should still cause a reaction with eNOS and synthesize nitric oxide. Not sure why any time period would effect this, except a lengthy time period where receptors are more tolerant causing the arginine uptake to be higher.

Muscle performance, etc. I can see. But nitric oxide production makes everything fishy. Either there was a wrong doing in the procedure or, it's just that, arginine does very little.

Anyone got any other studies?

 

[tim290280]

^^Yep; this review of it.

Acta Physiologica Scandinavica
Volume 162 Issue 3, Pages 401 - 409

Role of nitric oxide in skeletal muscle: synthesis, distribution and functional importance
M. B. REID

Over the last two decades, nitric oxide (NO) has been established as a novel mediator of biological processes, ranging from vascular control to long-term memory, from tissue inflammation to penile erection. This paper reviews recent research which shows that NO and its derivatives also are synthesized within skeletal muscle and that NO derivatives influence various aspects of muscle function. Individual muscle fibres express one or both of the constitutive NO synthase (NOS) isoforms. Type I (neuronal) NOS is localized to the sarcolemma of fast fibres; type III (endothelial) NOS is associated with mitochondria. Isolated skeletal muscle produces NO at low rates under resting conditions and at higher rates during repetitive contraction. NO appears to mediate cell–cell interactions in muscle, including vasodilation and inhibition of leucocyte adhesion. NO also acts directly on muscle fibres to alter cell function. Muscle metabolism appears to be NO-sensitive at several sites, including glucose uptake, glycolysis, mitochondrial oxygen consumption and creatine kinase activity. NO also modulates muscle contraction, inhibiting force output by altering excitation–contraction coupling. The mechanisms of NO action are likely to include direct effects on redox-sensitive regulatory proteins, interaction with endogenous reactive oxygen species, and activation of second messengers such as cyclic guanosine monophosphate (cGMP). In conclusion, research published over the past few years makes it clear that skeletal muscle produces NO and that endogenous NO modulates muscle function. Much remains to be learned, however, about the physiological importance of NO actions and about their underlying mechanisms.

So not an endorsement of supplementation by any means, but I can't read the whole thing due to the access to the article.

This one isn't exactly telling us anything about muscle, but clearly arginine does something in the long term

Circulation. 1998;97:2123-2128.)

Long-term L-Arginine Supplementation Improves Small-Vessel Coronary Endothelial Function in Humans
Amir Lerman, MD; John C. Burnett, Jr, MD; Stuart T. Higano, MD; Linda J. McKinley, RN; ; David R. Holmes, Jr, MD

Background—Coronary endothelial dysfunction is characterized by an imbalance between endothelium-derived vasodilating and vasoconstricting factors and coronary vasoconstriction in response to the endothelium-dependent vasodilator acetylcholine. Thus, the present double-blind, randomized study was designed to test the hypothesis that long-term, 6-month supplementation of L-arginine, the precursor of the endothelium-derived vasodilator NO, reverses coronary endothelial dysfunction to acetylcholine in humans with nonobstructive coronary artery disease.

Methods and Results—Twenty-six patients without significant coronary artery disease on coronary angiography and intravascular ultrasound were blindly randomized to either oral L-arginine or placebo, 3 g TID. Endothelium-dependent coronary blood flow reserve to acetylcholine (10-6 to 10-4 mol/L) was assessed at baseline and after 6 months of therapy. There was no difference between the two study groups in clinical characteristics or in the coronary blood flow in the response to acetylcholine at baseline. After 6 months, the coronary blood flow in response to acetylcholine in the subjects who were taking L-arginine increased compared with the placebo group (149±20% versus 6±9%, P<0.05). This was associated with a decrease in plasma endothelin concentrations and an improvement in patients' symptoms scores in the L-arginine treatment group compared with the placebo group.

Conclusions—Long-term oral L-arginine supplementation for 6 months in humans improves coronary small-vessel endothelial function in association with a significant improvement in symptoms and a decrease in plasma endothelin concentrations. This study proposes a role for L-arginine as a therapeutic option for patients with coronary endothelial dysfunction and nonobstructive coronary artery disease.

More support for its vasodilation effects when used with old people, but at least shows that supplementation does something:

Correction of endothelial dysfunction in chronic heart failure: additional effects of exercise training and oral L-arginine supplementation .
Journal of the American College of Cardiology , Volume 35 , Issue 3 , Pages 706 - 713
R . Hambrecht
OBJECTIVES

The aim of this study was to analyze whether L-arginine (L-arg.) has comparable or additive effects to physical exercise regarding endothelium-dependent vasodilation in patients with chronic heart failure (CHF).

BACKGROUND

Endothelial dysfunction in patients with CHF can be corrected by both dietary supplementation with L-arg. and regular physical exercise.

METHODS

Forty patients with severe CHF (left ventricular ejection fraction 19 ± 9%) were randomized to an L-arg. group (8 g/day), a training group (T) with daily handgrip training, L-arg. and T (L-arg. + T) or an inactive control group (C). The mean internal radial artery diameter was determined at the beginning and after four weeks in response to brachial arterial administration of acetylcholine (ACh) (7.5, 15, 30 μg/min) and nitroglycerin (0.2 mg/min) with a transcutaneous high-resolution 10 MHz A-mode echo tracking system coupled with a Doppler device. The power of the study to detect clinically significant differences in endothelium-dependent vasodilation was 96.6%.

RESULTS

At the beginning, the mean endothelium-dependent vasodilation in response to ACh, 30 μg/min was 2.54 ± 0.09% (p = NS between groups). After four weeks, internal radial artery diameter increased by 8.8 ± 0.9% after ACh 30 μg/min in L-arg. (p < 0.001 vs. C), by 8.6 ± 0.9% in T (p < 0.001 vs. C) and by 12.0 ± 0.3% in L-arg. + T (p < 0.005 vs. C, L-arg. and T). Endothelium-independent vasodilation as assessed by infusion of nitroglycerin was similar in all groups at the beginning and at the end of the study.

CONCLUSIONS

Dietary supplementation of L-arg. as well as regular physical exercise improved agonist-mediated, endothelium-dependent vasodilation to a similar extent. Both interventions together seem to produce additive effects with respect to endothelium-dependent vasodilation.

And the good old mice study that kicked it all off;

Effects of dietary arginine supplementation on protein turnover and tissue protein synthesis in scald-burn rats .
Nutrition , Volume 15 , Issue 7 - 8 , Pages 563 - 569
X . Cui

We assessed the effects of dietary arginine supplementation on protein turnover and organ protein synthesis in burned rats. Male Wistar rats weighing about 200 g underwent catheter jejunostomy and received scald burns covering 30% of the whole-body surface area. Animals were divided into a control group (n = 9) and an arginine group (n = 9) and continuously received total enteral nutrition for 7 d (250 kcal · kg−1 · d−1, 1.72 gN · kg−1 · d−1). Changes in body weight, plasma total protein, plasma albumin, urinary excretion of polyamines, nitrogen balance, whole-body protein kinetics, and tissue protein synthesis rates were determined. Whole-body protein kinetics and tissue fractional protein synthetic rates (Ks, percent/d) were estimated using a 24-h constant enteral infusion of 15N glycine on the last day. The changes in body weight were not different between the control and arginine groups. The urinary excretion of polyamines was higher in the arginine group than in the control group (P < 0.01). Burned rats enterally fed arginine-supplemented diet yielded significantly greater cumulative and daily nitrogen balance on days 3 and 5 than those fed a control diet (cumulative, P < 0.05; day 3, P < 0.01; day 5, P < 0.01). Whole-body protein turnover rate was significantly elevated in the arginine group as compared to that in the control group (P < 0.05). The Ks of rectus abdominis muscles were significantly increased in the arginine group in comparison to the control group (P < 0.01). We have shown that dietary arginine supplementation improved protein anabolism and attenuated muscle protein catabolism after thermal injury.

 

[Adam23]

^^^great info !!! thanks tim

 

[The_KM]

Solid studies, Timbo. Repped when able to.

Those reasons exactly, is why is I was interested in a nitric oxide product, I'd refrain from formulas and stick to arginine. Caffeine is just gravy.

 

[Braaq]

Surprising is more like it, I would have to say that my supplementation with NO products proves otherwise. So does several readings I have done on the subject and what I have learned in physio classes. This is just one study, lets see if we can find others. I will when I am not studying for a midterm. But good post, I am again surprised at that finding.