Type I cAMP-dependent protein kinase (PKA) regulatory α-subunit (RIα) expression is reduced upon global ex vivo cardiac ischemia-reperfusion (I/R) injury. A: immunoblot analysis of tissue homogenate from adult mouse hearts exposed to ex vivo global I/R injury. Control perfusion heart samples were compared with hearts treated with 25 min ischemia followed by 30 min of reperfusion injury. Opa1, optic atrophy protein 1; COXIV, cytochrome-c oxidase. Corresponding scatter plots show protein expression quantification for RIα (B; P = 0.0039), catalytic subunit of PKA (PKAc) (C; P = 0.0487), RIIα (D; P = 0.5978), and A-kinase anchoring protein 1 (AKAP1) (E; P = 0.0297). Data are presented as means ± SD; n = 4 biological replicates. *P < 0.05; **P < 0.01; n.s., not significant.