Effect of L-carnitine and propionyl-L-carnitine on endothelial function of small mesenteric arteries from SHR

Background: The effect of treatment with either 200 mg center dot kg (-1) of L-carnitine (LC) or propionyl-L-carnitine ( PLC) was studied on endothelial dysfunction of small mesenteric arteries (SMA) from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Methods: Systolic blood pressure (SBP) was measured and endothelial and vascular functions were assessed by the effect of carbachol (CCh) and phenylephrine (Phe). O (2) over bar produced by SMA and eNOS expression were evaluated by chemiluminescence and Western blot, respectively. Results: Although SBP was not affected, endothelial relaxation increased in both LC- and PLC-treated SHR. Nevertheless, the CCh-induced contraction remained sensitive to indomethacin in these rats. On the contrary, NO participation was increased in all the groups except for LC- treated WKY. Furthermore, high concentrations of Phe produced NO-dependent relaxation of SMA from PLC-treated rats. Both compounds decreased basal and NADPH-stimulated O (2) over bar in SHR toward values observed in WKY. Only PLC increased eNOS protein expression in SHR. Neither LC nor PLC affected endothelium-derived hyperpolarizing factor-induced relaxation. Conclusions: LC and its propionate improved endothelial responses of SMA from SHR by decreasing O (2) over bar production and thus increasing NO availability. PLC also increased NO synthesis by enhancing eNOS expression.