Mechanical effects of some prostanoids on isolated human oesophageal submucosal veins

The effects of prostaglandins E1, E2, F2 alpha, prostacyclin, and the thromboxane A2-mimic U46619 were investigated on isolated human oesophageal submucosal veins from the oesophageal body and the oesophagogastric junction. U46619 most potently, but also PGF2 alpha produced venocontraction without differences between preparations from the oesophageal body and the oesophagogastric junction. PGE1 and prostacyclin caused relaxation of vessels precontracted with U46619 (10(-9) M). PGE2 induced either contraction or relaxation, but biphasic effects in the same vessel segment were not seen. Indomethacin 10(-6) M inhibited the contractile responses to both noradrenaline and K+ (124 mM), suggesting that the agonists induced synthesis or release of vasoconstrictor prostanoids. Prostanoids exert potent mechanical effects in submucosal oesophageal veins and may be of physiological importance.