Click on image to view larger version.

Figure 2 Effect of oral treatment with isosorbide mononitrate (ISMN) on vasorelaxation induced by ISMN in aortic rings. Induction of in vivo nitrate tolerance in the ISMN-200 group is indicated by the rightward shift of the concentration response curve of ISMN (*p < 0.0001 by analysis of variance [ANOVA]). In contrast, there was no development of tolerance in ISMN-2 (p > 0.05 by ANOVA).