Diabetes Converts Arterial Regulation by Perivascular Adipose Tissue From Relaxation Into H2O2-Mediated Contraction

This study aims to reveal the reason for the increased force of 5-hydroxytryptamine-induced contraction of endotheliumdenuded skeletal muscle arteries of diabetic rats in the presence of perivascular adipose tissue (PVAT). Our data on rat gracilis arteries show that i) PVAT of skeletal muscle arteries of healthy and diabetic rats releases hydrogen peroxide (H2O2), ii) higher concentrations of 5-hydroxytryptamine increase the production of H2O2 in PVAT; iii) an enhanced PVAT production of H2O2 is the main, if not the only, reason for the sensitization of arterial contraction to 5-hydroxytriptamine-induced contraction in diabetes and iv) endothelium antagonizes the effect of PVATderived H2O2