Septic shock down-regulates L -arginine /NOS /NO pathway of platelet and aortic intima in rats

AIM: To investigate alteration and cross link of the aortic and platelet endogenous L -arginine/NOS/NO pathway induced by septic shock.METHODS: The septic shock model was made in rats by caecal ligation and puncture. NO^-₂/NO^-₃ production released from aortic and platelet was measured with Greiss assay. NOS activity and L-arginine transport activity were detected by isotope tracer method. RESULTS: Both in early and late stage of septic shock, NO^-₂/NO^-₃ production, NOS activity, and the L-arginine transport from the aorta intima and platelets were obviously decreased, while those of the aorta media and adventitia were obviously increased (P<0.01), but high-affinity L-arginine transport activity from the aorta intima and platelets was increased in early stage of septic shock (P>0.05 and P<0.05), as compared with the sham group, respectively. The inhibitory effects of NO^-₂/NO^-₃, NOS activity and the L-arginine transport showed a positive correlation between platelet and aortic intima (P<0.01). CONCLUSION: Septic shock down-regulates endogenous L-arginine/NOS/NO pathway in aortic intima and platelet, up-regulates L-arginine/NOS/NO pathway of aortic media and adventitia. Detection of the alteration of endogenous L-arginine/NOS/NO pathway in platelet might act as an indirect method to assess the endothelial dysfunction involving the pathogensis of septic shock.