ABSTRACT
Male Sprague-Dawley rats aged 7-9 weeks and weighing 200-270g were used (Kyudo, Fukuoka, Japan). The main branches of the superior mesenteric arteries and saphenous vein
were excised under anesthesia with diethyl ether inhalation and placed on a plate containing cold modified Krebs-Ringer bicarbonate solution [millimolar concentration: NaCl 118.3, KCl 4.7, CaCl2 2.5, MgSO4 1.2, KH2PO4 1.2, NaHCO3 25.0, edetate calcium disodium (CaEDTA) 0.026, and glucose 11.1] (control solution) aerated with 95% O2 and 5% CO2. In some experiments, mesenteric artery was cannulated with a 24-gauge catheter (SurfloTM, Terumo Co., Ltd., Tokyo, Japan), and either gabexate mesilate (103 M) or saline was perfused through the catheter for 5min. The blood vessels were cleaned of adherent connective tissue and cut into rings (1mm long). Some experiments were performed in the presence of indomethacin (105 M) or L-nitroarginene methyl ester (L-NAME; 104 M) to inhibit the formation of vasoactive prostanoids or nitric oxide, respectively.
