HYPOXIA AND RESPONSE OF HUMAN UMBILICAL ARTERY STRIPS TO 5-HYDROXYTRYPTAMINE - ROLE OF PROSTAGLANDIN-F2-ALPHA

1. This article examines the effects of hypoxia on the contractile res ponse of isolated human umbilical artery strips to 5-hydroxytryptamine (5-HT). 2. Hypoxic conditions produce a large increase in the contrac tile response to 5-HT without a significant alteration of the sensitiv ity evaluated at the level of the pD(2) value. Indomethacin (10 mu M) reduced hypoxia-induced potentiation of the response to 5-HT and decre ased the response to the monoamine under oxygenated conditions. 1-NAME (100 mu M) did not further increase the effect of hypoxia on the vess el response to 5-HT and increased the response to 5-HT under oxygenate d conditions. 3. Taken together, these results suggest that, at least partially, the response of human umbilical artery strips to 5-HT depen ds on 5-HT release of a contracting prostanoid which is a product of t he cyclooxygenase pathway, Furthermore, during hypoxia in human umbili cal artery strips, there appears to be impairment of the basal product ion and/or release of EDRF/NO. 4. A subthreshold concentration of pros taglandin F-2 alpha (1 nM) potentiates the response to 5-HT in indomet hacin-pretreated umbilical artery strips. The data raise the possibili ty that prostaglandin F-2 alpha might be the prostanoid released durin g hypoxia, which in turn potentiates the response of the human umbilic al artery to 5-HT. Copyright (C) 1997 Elsevier Science Inc.