OBJECTIVE Nitrate tolerance is likely attributable to an increased production of reactive oxygen species (ROS) leading to an inhibition of the mitochondrial aldehyde dehydrogenase (ALDH-2), representing the nitroglycerin (GTN) and pentaerythrityl tetranitrate (PETN) bioactivating enzyme, and to impaired nitric oxide bioactivity and signaling. We tested whether differences in their capacity to i...

Long-term use of most organic nitrates is limited by development of tolerance, induction of oxidative stress and endothelial dysfunction. In this issue of the BJP, Schuhmacher et al. characterized a novel class of organic nitrates with amino moieties (aminoalkyl nitrates). Aminoethyl nitrate was identified as a novel organic mononitrate with high potency but devoid of induction of mitochondrial...

Organic nitrates represent a class of drugs which are clinically used for treatment of ischemic symptoms of angina as well as for congestive heart failure based on the idea to overcome the impaired NO bioavailability by "NO" replacement therapy. The present paper is focused on parallels between diabetes mellitus and nitrate tolerance, and aims to discuss the mechanisms underlying nitrate resist...

Anti-ischemic therapy with organic nitrates is complicated by tolerance. Induction of tolerance is incompletely understood and likely multifactorial. Recently, increased production of reactive oxygen species (ROS) has been investigated, but it has not been clear if this is a direct consequence of the organic nitrate on the vessel or an in vivo adaptation to the drugs. To examine the possibility...

BACKGROUND Organic nitrates such as nitroglycerin and isosorbide dinitrate are useful in the treatment of congestive heart failure (CHF), but tolerance develops rapidly during continuous administration. Because combination therapy of nitrate and hydralazine has been shown to provide both short- and long-term benefit but nitrate alone produces hemodynamic tolerance, we questioned whether hydrala...

BACKGROUND The basis for progressive attenuation of the effects of organic nitrates during long-term therapy (nitrate tolerance) remains controversial; proposed mechanisms include impaired nitrate bioconversion resulting in decreased release of nitric oxide (NO) from nitrates and/or increased NO clearance through a reaction with incrementally generated superoxide (O(2)(-)). METHODS AND RESULT...

Nitroglycerin (GTN) and other organic nitrates are important drugs commonly used in cardiovascular medicine, and, more recently, in obstetrics as tocolytic agents.1 The development of tolerance, ie, the reduction in effect or the requirement for higher doses that appears after continuous use,2 is a major factor limiting the efficacy of these drugs. Despite their clinical importance in the thera...

Statins have been reported to show preventive effect on nitrate tolerance in normal rats, but there are no reports on their effect in diabetic animals. In this study, diabetes was induced in male wistar rats by a single intraperitoneal injection of streptozotocin (45 mg/kg). Five groups of diabetic and five groups of normal rats were treated; groups 1 (of normal and diabetic rats) received ator...

The first part of this review provided a synopsis of the recent literature about superoxide anion (·O2 ) production, endothelial dysfunction, and the neurohormonal activation that follow long-term administration of organic nitrates. In this issue of Circulation, we will try to integrate these observations with other separate, and, to a certain extent, antagonistic hypotheses that have been prop...

Clinical studies have suggested that long-term nitrate treatment does not improve and may even worsen cardiovascular mortality, and the possible role of nitrate tolerance has been suspected. Nitrate tolerance has been recently shown to increase vascular superoxide and peroxynitrite production leading to vascular dysfunction. Nevertheless, nitrates exert direct cardiac effects independent from t...