Influence of mechanical endothelium removal techniques and conservation conditions on rat aorta responses

Endothelial denudation of aortas induces a lack of relaxation to acetylcholine and enhancement of response to noradrenaline. These modified responses have been studied in rat aorta by using different techniques for mechanical removal of the endothelial layer and maintenance conditions. Rubbing the artery with cotton inside the organ bath preserves the enhancement of response to noradrenaline, and this effect is not present by rubbing the aortas with filter paper outside the organ bath. Both techniques abolished the relaxant response to acetylcholine. The endothelium dependent effects are not observed by conservation of the artery at room temperature during 1 h. The relaxant response to acetylcholine after this period is approximately 29% of the control. These effects were preserved when the conservation temperature was maintained at 4 degrees C and/or the solution was being bubbled with oxygen.