NOdonatorer

NO-donators, or NOdonatorer, are chemical compounds designed to release nitric oxide (NO) under physiological conditions. NO is a small signaling molecule that modulates vascular tone, neurotransmission, and immune responses. NO-donators are used both as research tools to study NO signaling and as therapeutic agents to induce vasodilation in certain medical conditions.

NO-donators can be broadly categorized by their NO-release mechanisms. Organic nitrates such as nitroglycerin and isosorbide dinitrate release NO after metabolic activation and are used clinically to treat angina and heart failure. Sodium nitroprusside releases NO directly but also yields cyanide as a byproduct, and is employed in hypertensive emergencies and during some surgical procedures. S-nitrosothiols (RSNOs) liberate NO through transnitrosation or reductive pathways, and are studied as endogenous and exogenous NO carriers. NONOates (diazeniumdiolates) generate NO spontaneously in aqueous solutions and serve as versatile research NO donors with controllable release. Other donors include metal-nitrosyl complexes and photo-triggered donors, which release NO upon light exposure.

Mechanistically, NO activates soluble guanylate cyclase (sGC) in target cells, increasing cyclic GMP (cGMP) levels and causing smooth muscle relaxation. This pathway underpins much of NO-donor pharmacology, particularly in lowering vascular resistance and blood pressure. Clinical use is tempered by tolerance with some nitrates, potential hypotension, headaches, and interactions with other vasodilators or PDE5 inhibitors.

NO-donators remain important both in basic biology and clinical practice, offering insights into NO signaling and providing therapeutic options for cardiovascular conditions, while ongoing research seeks improved donors with targeted delivery and reduced side effects.