In our study, however, this phenomenon occurs only in sMAs of SHR, which theoretically could be the result of the involvement of silent information regulator T1 (sirtuin-1, SIRT1) and AMP-activated protein kinase (AMPK) pathway, that was suggested to restore impaired EDH-mediated relaxation in mesenteric artery at the early stage of hypertension (12 weeks old animals) but not in age-matched WKY [22] or normotensive Sprague-Dawley rats [53]. The gene discussed is SIRT1; the disease is Hypertension.