Fig. 9.

MAO-A and OCT3 coordinate cardiac fight-or-flight response. M-mode echocardiography was recorded for 2 min at baselines and for 8 min after drug administration. The maximal cardiac response was reported. A Representative echocardiography images of MAO-A-CKO mouse heart before and after EPI stimulation (100 µg/kg, i.p.) with and without CORTI pretreatment (200 µg/kg, i.p., 5 min). B The schematic depicts that inhibiting OCT3 by CORTI suppresses the SR-localized β₁ARs activation in MAO-A-CKO hearts. C The EF and HR of MAOA-A-FF and CKO mice before and after treated with EPI and CORTI described in A. n = 8 mice in each condition. D Representative echocardiography images of OCT3-KO mouse heart before and after EPI stimulation (100 µg/kg, i.p.) with and without MAOi (0.4 mg/kg, i.p.). E The schematic depicts that deletion of OCT3 prevents the effects of MAOi on enhancing the SR-localized β₁AR signaling. F The EF and HR in WT and OCT3-KO mice before and after EPI and MAOi treatment described in D. n = 8 KO mice. Data were shown as mean ± SD. p values were obtained by one-way ANOVA followed by Tukey’s test