NPR1 and myocardial ischemia: Four adenylate cyclase genes (ADCY1, 3, 5, 9) were significantly downregulated under IHD condition, while no significant difference was detected between the groups among mRNAs encoding for guanylate cyclases (GUCYs) and the natriuretic peptide receptors (GUCY2A, GUCY2B, and NPR-3) (Table 3).