RESUMEN
Cationic amino acid transport activity in a canine lens epithelial cells (LEC) line was investigated. The transporter activity of arginine was 0.424 ± 0.047 nmol/mg protein min, while the presence of N-ethylmaleimide, an inhibitor of the canine cationic amino acid transporter (CAT), reduced transport activity by 30%. A full-length cDNA sequence of canine CAT1 was 2558 bp long and was predicted to encode the 629 amino acid polypeptides. The deduced amino acid sequence of canine CAT1 showed similarities of 92.1% and 88.6% to those of the human and mouse, respectively. Western blot analysis detected a band at 70 kDa in a membrane protein sample of LEC. RT-PCR analysis confirmed that CAT1 was ubiquitously detected in all tissues examined.
Asunto(s)
Arginina/metabolismo , Transporte Biológico/genética , Transportador de Aminoácidos Catiónicos 1/fisiología , Células Epiteliales/metabolismo , Cristalino/citología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Transportador de Aminoácidos Catiónicos 1/antagonistas & inhibidores , Transportador de Aminoácidos Catiónicos 1/química , Transportador de Aminoácidos Catiónicos 1/genética , Células Cultivadas , ADN Complementario/genética , Perros , Etilmaleimida/farmacología , Humanos , Masculino , RatonesRESUMEN
UNLABELLED: Ginsenoside Rb1 and Rg1 are major components of Panax notoginseng (P.N.), an herb with known clinical efficacy in hypertension and myocardial ischemia in Eastern countries. This investigation is to elicit the mechanism of these components in hypertension via their effect on vascular reaction. To assess the ability of P.N. in hypertension, P.N. extracts were injected in spontaneously hypertensive rats (SHR) via the vena caudalis; Low dosages of P.N. extracts significantly lowered blood pressure in SHR. Examination with Rb1 and Rg1 revealed significant vasodilatation using mouse coronary arteries in a dose-dependent manner. Rb1- and Rg1-induced vasodilatation was blocked by pre-incubation with eNOS and PI3K inhibitors. Coronaries of eNOS-/- mice showed attenuated vasodilatation with Rb1 and Rg1. In addition, both Rb1 and Rg1 induce nitric oxide (NO) generation through increasing the phosphorylation of eNOS, activating Na+-independent l-arginine transport, and stimulating cationic amino acid transport (CAT)-1 mRNA expression in cultured endothelial cells. CONCLUSION: Ginsenoside Rb1 and Rg1 increased endothelial-dependent vessel dilatation through the activation of NO by modulating the PI3K/Akt/eNOS pathway and l-arginine transport in endothelial cells. These findings may have important implications for understanding the mechanisms of clinical efficacy of the herb P.N. when used in the regulation of blood pressure.