... factor, change in arterial pressure and activation of sympathetic nerves, as well as direct effects on the kidney [ 16 ]. We and others have shown that opioids also induce nitric oxide synthase (NOS), hemoxygenase-1 (HO-1) and cyclooxygenase-2 (COX-2) [ 17, 18, 19 ] which are potent vasodilators. Further...