Effect of L-carnitine supplementation on the sGC/cGMP pathway in vascular relaxing responses from exercised rats
© Priviero et al; licensee BioMed Central Ltd. 2009
Published: 11 August 2009
It has been largely documented the beneficial effects of physical training on the endothelium-derived relaxing response by increasing nitric oxide production and/or its bioavailability to the smooth muscle . L-carnitine (L-Car) has been used as important supplement to regulate body composition associated with lipid metabolism. However, no studies exist investigating the effect of L-Car intake associated with dynamic exercise on the NO-independent sGC/cGMP pathway in the vascular responsiveness in rats. Thus, the aim of this work was to investigate the effect of L-Car supplementation on the NO-independent sGC/cGMP pathway in aortic and mesenteric rings in trained rats.
Male Wistar rats (344 ± 6 g) were divided into three groups: sedentary (SD), sedentary supplemented (SDS) and trained supplemented (TRS). Animals were trained in a treadmill with an intensity of 70–80% of maximal oxygen consumption, in sessions of 60 minutes, 5 days a week. Run training (RT) was performed simultaneously to L-Car intake (0.2 g/kg daily, given in the drinking water) for 4 weeks. Concentration-response curves were obtained for sodium nitroprusside (SNP) in isolated aortic and mesenteric rings. Plasma SOD activity and catalase levels were measured.
Potency (pEC50) and maximal responses (EMAX) for sodium nitroprusside (SNP) in mesenteric and aortic rings from sedentary and exercised rats treated with L-Car supplementation for 4 weeks.
8.31 ± 0.06
103 ± 2
7.90 ± 0.13
109 ± 2
8.81 ± 0.04*
103 ± 3
7.99 ± 0.13
95 ± 3
8.58 ± 0.03*
109 ± 4
8.61 ± 0.07*
114 ± 5
In conclusion, L-Car supplementation associated with physical exercise training was effective to reduce body weight gain in rats. Furthermore, an increase in the relaxing response for SNP in aortic and mesenteric rings from exercise rats treated with L-Car supplementation. These findings suggest that physical exercise-induced shear stress could affect directly the sGC/cGMP signaling pathway in vascular tissues.
Financial Support: FAPESP
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