2.3. Experimental Procedure of Vasorelaxation Studies with Aortic Rings

Thoracic aortas from healthy male Wistar rats were rapidly excised, cleaned of the surrounding tissue and cut into rings of 2 mm length under sterile conditions. The measurement of changes in the vasoreactivity of the explanted aortic rings were performed in an organ chamber. The rings were mounted on platinum hooks in 10 mL jacketed organ baths containing a modified Krebs–Henseleit solution (144 mM NaCl, 5.9 mM KCl, 1.6 mM CaCl₂, 1.2 mM MgSO₄, 1.2 mM KH₂PO₄, 25 mM NaHCO₃, 11.1 mM D-glucose) and 1 µM diclofenac. The solution in the bath was maintained at a pH of 7.4 and at 37 °C, with a gas mixture of 5% CO₂ and 95% O₂. After equilibration, the reactivity of rings was tested with KCl (40 mM). Non-functional rings were discarded. Rings were precontracted with phenylephrine (PE, 0.05 µM) before treatments.