EFFECTS OF SIMULATED MYOCARDIAL ISCHEMIC CONDITIONS ON THE RESPONSES OF ISOLATED HUMAN UMBILICAL ARTERY STRIPS TO 5-HYDROXYTRYPTAMINE AND PROSTAGLANDIN-F2-ALPHA

1. The effects of simulated myocardial ischemic conditions on the cont ractile response of isolated human umbilical artery (HUA) strips to 5- hydroxytryptamine (5-HT) and prostaglandin F-2 alpha(PGF(2 alpha)) wer e studied. 2. During simulated myocardial ischemic conditions the cont ractile response of HUA strips to 5-HT was lower than the response to the monoamine under oxygenated conditions. Under simulated ischemic co nditions the response to 5-HT was further depressed by the cyclooxygen ase inhibitor indomethacin (10 mu M) and increased by the NO synthase inhibitor L-NAME (100 mu M). 3. During simulated ischemic conditions t he response of the HUA to a submaximal concentration of PGF(2 alpha) ( 3 mu M) was reduced. Indomethacin (10 mu M) further reduced the respon se to the prostanoid whereas L-NAME (100 mu M) enhanced the response t o PGF(2 alpha). 4. It is concluded that during simulated myocardial is chemic conditions lactate negatively modulates the contractile respons e of HUA strips to 5-HT. Apparently, during simulated myocardial ische mic conditions in the HUA the production and/or release of EDRF/NO was not affected. (C) 1997 Elsevier Science Inc.