Objective    To investigate the role and possible mechanism of Cx40/43 regulating the endothelium-dependent vasorelaxation reactivity following hemorrhagic shock in rats.     Methods    Superior mesenteric arteries (SMAs) was taken out from SD rats

and cut into 2-3 mm segments. Cx40/43 antisense oligodeoxyribonucleotide (Cx40/43 AODN) was transfected into the segments respectively

and then the transfected and non-transfected segments were cultured in a hypoxia culture tank. The changes of vasodilation response

the activities of myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP) were observed.     Results    Cx40 AODN improved the vasorelaxation response of SMA

while Cx43 AODN attenuated it. Cx40/43 AODN had no effect on the MLCK and MLCP activities of SMA.     Conclusion    Both Cx40 and Cx43 have important effects on regulating the endothelium-dependent vasorelaxation reactivity in rats following hemorrhagic shock. The regulation has no relation with the activities of MLCP and MLCK of SMAs.