Introduction and objectives: Ischemia and ischemia/reperfusion can dephosphorylate and redistribute Connexin 43 (Cx43). But it is unknown whether no-reflow phenomenon has an effect on the expression and distribution of Cx43 after acute infarction and reperfusion. Methods: 21 open-chest pigs were divided into three groups. Left anterior descending artery (LAD) occlusion for 90. min before 180. min of reperfusion was made in ischemia/reperfusion group. The pigs in ischemia groups were either subjected to LAD ligation for 90. min or for 270. min. No-reflow and risk regions were determined pathologically by dye staining. Cx43 expression was measured by western blotting and quantitative RT-PCR analysis. Cx43 spatial distribution was shown by immunofluorescence examination. Results: The content of phosphorylated and mRNA of Cx43 were higher in reflow region than in the no-reflow or sustained ischemic region. The distribution of Cx43 was also altered in no-reflow region. Conclusions: There are some differences in synthesis, expression and distribution of myocardial Cx43 at microvascular level after ischemia/reperfusion. Cx43 is partially rephosphorylated with reperfusion only in the reflow myocardium. © 2011 Elsevier Inc.