Chronic intermittent nitroglycerin produces a sustained basal hypersensitivity, and evokes acute hyperalgesia. Male C57BL/6J mice were treated every other day for 9 days with nitroglycerin (10 mg/kg, i.p.) or 0.9% saline control. A) Basal mechanical responses, assessed prior to vehicle or nitroglycerin administration, significantly decreased in the nitroglycerin group during the treatment period (n=12/group, 2-way RM ANOVA and Holm-Sidak post-hoc analysis. p<0.001 for drug, time and interaction; ***p<0.001 as compared to vehicle. B) Post-treatment mechanical responses, assessed 2 hours after vehicle or nitroglycerin injection, were significantly decreased in the nitroglycerin group on each test day. 2-way RM ANOVA, p<0.001 for time.