L‐Arginine administration increases blood flow of skin and soleus muscle of rats

Abstract

Objective It has demonstrated that exogenous L-Arginine (L-Arg) elicited vasodilation through the action of nitric oxide, and low dose LArg administration increase skin capillary blood flow without affecting systemic blood pressure. However, it is unknown whether low dose LArg increases blood flow in other organs. Method Male SD rats (350~450 g) were continuously anesthetized by infusion of mixture of ketamine and xylazine into femoral vein, and the some organ or tissue blood flow were measured before and after L-Arg 0 to 450 mg/kg infusion by the non-radioactive colored dye-extraction microsphere technique. The organ or tissue measured blood flow were skin, epididymal fat, kidney, spleen, duodenum, liver, heart, brain, gastrocnemial and soleus muscle. Results L-Arg 150 mg/kg infusion significantly increased blood flow in soleus muscle, skin, duodenum, heart and brain compared with blood flow before infusion. L-Arg 50 mg/kg slightly increased blood flow in the same organ or tissue, but the increasing effect for blood flow in soleus muscle was similar between 50 and 150 mg/kg. While higher dose L-Arg (300 and 450 mg/kg) hardly increase blood flow in every organ. Conclusion These results suggest that moderate exogenous L-Arg is effective for blood flow increment in soleus muscle. Therefore, the effect of L-Arg on the peripheral blood flow may differ in tissues or organs, and further investigation is needed to clarify the mechanism of L-Arg effect.