Maximal responses in mean arterial blood pressure (MAP) to acute bolus application of INS45973 (P2Y2/4 agonist) in connexin 37 knockout mice (Cx37−/−, n = 5). In Cx37−/− mice, application of INS45973 induced a dose-dependent, rapid decrease in blood pressure (left side, early phase) which was significantly impaired compared to wild-type (WT) mice. The dose-dependent rise in blood pressure above basal values following the initial decrease in Cx37−/− mice was also significantly impaired compared to WT mice (right side, late phase). The dose-dependent blood pressure decrease in response to acetylcholine was comparable between Cx37−/− and WT mice and not followed by an acute blood pressure increase above basal values. Some error bars are covered. *P < 0.05 vs. WT (two-way anova with repeated measures followed by Dunnett’s test).