ABSTRACT
Objective To inveatigate the effect of 15-HETE, a metabolite of arachidonic acid, on isolated hypoxic pulmonary arterial ringa ( PARs) , trying to find appropriate treatment for pulmonary hypertension and its complications during anesthesia in order to avoid hypoxemia. Methods Sixteen healthy Wistar rats of either sex weighing (230 ? 10) g were randomly divided into two groups : A control group breathing fresh air (FiO2 =21%) and B hypoxia group breathing hypoxic air (N2 = 90% , O2 = 10% ) in a hypoxic box. After breathing hypoxic air for 9 days the animals were anesthetized. Heart and lungs were immediately removed and PARs (0.5-1.0 mm in diameter and 3 mm in length) were prepared. Four PARs were prepared from each animal. The PARs were suspended in baths filled with Krebs-Hensleit (K-H) solution maintained at 37℃ and aerated with 95% O2 and 5% CO2. Preload was gradually increased to 0.3 g in 30 min. The isometric tension was measured using a four-channel force-displacement transducer. 15-HETE was added to K-H solution and the concentration was gradually increased from 10-8 to 10-6 mol?L-1 at 5 min intervals. Contractility of PARs was analyzed by a software of Medlab 6.0. Concentration-tension curve was drawn and contraction rates were calculated. 2 mmol?L-1 4-AP, 10-2 mol?L-1 TEA and 10-6 mol?L-1 GLYB were added to separate K-H solution baths and 40 min later 15-HETE was added in order to detennine the effect of difierent potassium channel blockers on contraction response of PARs to 15-HETE. Results With increasing concentration from 10-8 to 10-6 mol?L-1 , 15-HETE increased PARs tension gradually in a dose-dependent manner from 106% ?6% to 139% ? 4% in group A and from 113% ?6% to 163% ?6% in group B. The difference in PARs tension between group A and B was statistically significant (P