Effects of indomethacin on venoconstrictor responses to bradykinin and norepinephrine

In order to determine whether the venoconstrictor response to BK was dependent on prostaglandin (PG) synthesis, effects of indomethacin (INDO) on responses to bradykinin (BK) and norepinephrine (NE) were studied in canine lateral saphenous vein. Cumulative dose-response curves (10⁻⁹-10⁻⁶M BK or NE) were done in the presence and absence of INDO (10⁻⁶M). In the presence of INDO, responses to BK were markedly enhanced while responses to NE were unchanged. After prolonged periods in the bath, responses to BK were enhanced in control strips while responses of strips which had been treated with INDO were depressed. These results suggest that BK does not normally cause venoconstriction by stimulating synthesis of a venoconstrictor PG and that the increase in response to BK after prolonged periods in the bath may be related to changes in PG synthetase.