Overview
What is it?
Nitric Oxide (NO) is a gas that acts as a signaling molecule in the body . It is naturally produced from the amino acid L-arginine in a variety of tissues, including the cells that line blood vessels, which are known as endothelial cells .
How does it work?
Nitric Oxide primarily works by relaxing blood vessels, a process known as vasodilation . It does this by activating an enzyme called guanylate cyclase, which leads to an increase in a molecule called cyclic guanosine monophosphate (cGMP) . This cGMP then causes the smooth muscles in the blood vessel walls to relax, widening the vessels and increasing blood flow . In skeletal muscle, NO can modulate contractile function through various mechanisms, including post-translational modifications of myofibrillar proteins, affecting excitation-contraction coupling, myofilament function, and neuromuscular transmission .
What are the benefits?
Nitric Oxide has several benefits, particularly related to its role in vasodilation. It can enhance blood flow to muscles, which may improve exercise performance and recovery . In the cardiovascular system, NO helps regulate blood pressure and improves blood flow . In addition to its cardiovascular effects, NO also plays a role in neurotransmission, immune responses, and inflammation . It also has been found to enhance the rate of isometric force development, unloaded shortening velocity, peak power, and optimize muscle activation during fused tetanus .
Effectiveness
What does the research say?
Research suggests that Nitric Oxide signaling, particularly through dietary nitrate supplementation, may enhance muscle contractile properties . This can include increasing submaximal force and peak power, which may have therapeutic and ergogenic implications for aging, disease, and athletic performance . Studies have also shown that Nitric Oxide is involved in myogenesis, the process of muscle formation and repair, especially after muscle injuries .
Side Effects
Oxidative tissue damage
The formation of highly reactive hydroxyl radicals from Nitric Oxide can potentially lead to oxidative damage in tissues .
Impaired energy metabolism
Nitric Oxide might interfere with the body's ability to efficiently produce energy .
Inflammation
NO can potentially promote inflammation in the body .
DNA damage
There is a possibility that Nitric Oxide could cause damage to DNA .
Paradoxical hypoxia
Although rare, a case of paradoxical hypoxia (low oxygen levels) was reported in a newborn infant in clinical studies .
Increased bleeding time
An increase in bleeding time has been observed in adult volunteers in clinical studies, though this is generally not significant in clinical practice .
Evidence
Clinical Studies & Trials
[1] Endothelial dysfunction and vascular disease - a 30th anniversary update.
This review discusses the role of the endothelium in relaxing underlying vascular smooth muscle through the release of vasodilator substances, particularly Nitric Oxide (NO). NO activates soluble guanylyl cyclase in vascular smooth muscle cells, producing cyclic guanosine monophosphate (cGMP) which initiates relaxation.
View study[2] Endothelium-derived hyperpolarizing factor.
This paper discusses endothelium-dependent responses in isolated arteries, focusing on acetylcholine-induced hyperpolarization. It highlights the role of endothelium-derived hyperpolarizing factor (EDHF), distinct from nitric oxide, in this process.
View study[3] Nitric oxide and skeletal muscle contractile function.
This review explores Nitric Oxide's role as a complex modulator of skeletal muscle contractile function. NO can enhance or decrease force and power output, and it modulates muscle function through mechanisms involving post-translational modifications of myofibrillar proteins.
View study[4] The pharmacology of inhaled nitric oxide.
This review discusses the multifaceted biological roles of Nitric Oxide, particularly its vasodilatory effects. It details how NO, synthesized from L-arginine, influences various systems including cardiovascular, neurological, and immunological.
View study[5] Nitric oxide.
This paper reviews Nitric Oxide's diverse biological activities, including its role in smooth muscle relaxation, neurotransmission, and modulation of inflammation. It also discusses ongoing studies on the modulation of NO in various medical conditions.
View study[6] Nitric oxide in myogenesis and therapeutic muscle repair.
This review focuses on the role of Nitric Oxide in skeletal muscle physiology and myogenesis. It discusses NO's functions in muscle repair and its potential therapeutic applications in muscular dystrophy.
View study[7] Nitric oxide and the cardiovascular system: cell activation, vascular reactivity and genetic variant.
This review explores the role of Nitric Oxide in the cardiovascular system, focusing on its function as an endothelium-derived relaxing factor. It discusses the mechanisms of cell activation of NO synthase (NOS) and the role of genetic variants in cardiovascular phenotypes.
View study[8] NO: the primary EDRF.
This paper discusses the discovery and identification of Nitric Oxide as the primary endothelium-derived relaxing factor (EDRF). It highlights NO's central role in regulating vascular tone and homeostasis.
View study