Inhibition of nitric oxide synthase with L-NAME in healthy volunteers significantly increased blood pressure (P<0.01) but did not alter platelet membrane expression of P-selectin.
Does intravenous L-NAME followed by l- or d-arginine alter P-selectin expression and blood pressure in healthy male volunteers?
Inhibition of nitric oxide synthase increases blood pressure but does not alter platelet membrane expression of P-selectin in healthy volunteers.
Inhibiting platelet and endothelial nitric oxide production favours platelet adhesion and aggregation, and arterial vasoconstriction. This study investigated the effect of NG-nitro-l-arginine methyl ester (L-NAME), a stereospecific inhibitor of nitric oxide synthesis, on P-selectin expression on platelets, platelet-derived microparticles and platelet-leucocyte aggregates, and on soluble P-selectin levels. Twelve healthy male volunteers were infused intravenously with L-NAME and then with a 10% solution of either l- or d-arginine. Blood pressure responses were recorded and whole blood and serum collected at baseline and after each infusion. P-selectin expression was analysed in all samples by flow cytometry. Serum levels of soluble P-selectin were batch analysed using an enzyme-linked immunosorbent assay at the end of the study. P-selectin expression on platelets, platelet-derived microparticles and platelet-leucocyte aggregates did not vary significantly from baseline levels following the infusion of L-NAME or l- or d-arginine. However, endothelial nitric oxide synthase inhibition caused a marked elevation of arterial blood pressure (P < 0.01) that was restored to pretreatment values by l- but not d-arginine. Serum levels of the soluble form decreased significantly (P = 0.001) following the infusion of l- and d-arginine compared with samples taken at baseline and following L-NAME infusion. In conclusion, inhibition of constitutive nitric oxide synthase in the endothelium and platelets produced significant increases in blood pressure but did not alter platelet membrane expression of P-selectin.
Ritchie et al. (Fri,) conducted a other in Healthy volunteers (n=12). L-NAME followed by l- or d-arginine vs. Baseline was evaluated on P-selectin expression on platelets, platelet-derived microparticles and platelet-leucocyte aggregates, and soluble P-selectin levels. Inhibition of nitric oxide synthase with L-NAME in healthy volunteers significantly increased blood pressure (P<0.01) but did not alter platelet membrane expression of P-selectin.
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