Vascular pharmacology
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Vascular pharmacology · Dec 2005
Nitroglycerin-patch induced tolerance is associated with reduced ability of nitroglycerin to increase exhaled nitric oxide.
Nitroglycerin (GTN), used in the treatment of ischemic heart disease, acts through the liberation of nitric oxide (NO). However, its clinical use is limited due to tolerance development. Expired NO was used as an indicator of GTN-bioactivation and was measured together with plasma nitrite and mean arterial pressure (MAP) during GTN indicator infusions. ⋯ This indicates that expired NO could serve as an indicator of NO generation from GTN in the vascular system. We conclude that GTN tolerance is associated with reduced capacity to generate NO from GTN. Care should be taken in using MAP-reduction to evaluate tolerance since high indicator doses could liberate sufficient amounts of NO to elicit maximal MAP decrease even in tolerant animals.