ADRB2 and type 2 diabetes mellitus: Based on these findings, the current study was conducted to investigate (1) the effect of sacubitril/valsartan on cardiac contraction/relaxation in comparison with valsartan using β-AR agonists and (2) the effect of these treatments on diastolic downstream components in a rat model of type 2 diabetes, induced by a high-fat diet (HFD) plus low-dose streptozotocin (STZ).