Characterization of vascular dysregulation in meriones shawi after high-calorie diet feeding.

The present study was initiated to characterize vascular dysregulations (contraction and relaxation) associated with metabolic defects in Merions shawi, a rodent from the gerbillidae family, submitted to 12 weeks high-calorie diet. This diet induces a type 2 diabetes/metabolic syndrome phenotype with hypertension. In diabetic meriones, body weight increase was associated with hyperglycemia, increased insulinemia, and insulin resistance. Compared to lean meriones, diabetic meriones showed decreased aorta contraction to noradrenaline, which was normalized after NOS inhibition. Endothelium-dependent relaxation to carbachol was enhanced, while relaxing effects of the NO donor SNAP and of diazoxide were unchanged. Insulin-evoked relaxation was depressed in aorta from diabetic meriones, and L-arginine relaxed contracted arteries from diabetic meriones, but not from lean meriones. Urine NOX level and iNOS mRNA muscle expression were significantly higher in diabetic meriones compared to lean animals. These data strongly suggest that iNOS may have a pathogenic role in vascular dysfunction observed in diet-induced diabetic meriones.