Effects of prostaglandins and endoperoxide analogs on canine saphenous vein

Contractile effects of prostaglandins (PGs) have not been widely studied in the canine saphenous vein, as in vitro model for venous function. We studied responses to two PG endoperoxide analogs (PGEA) and to monoenoic and bisenoic PGs of the A, B, E, and F series in helical strips of canine saphenous veins. Isometric changes in force were measured. All agents elicited marked contractions. PGEA were several orders of magnitude more potent than either primary PGs or other venoconstrictors, including norepinephrine. E- and A-types PG had unusual concentration and contraction at high concentration. B-types PG evoked a biphasic contractile response. Bisenoic PGs tended to be more potent than monoenoic PGs of the same type. These results show that canine saphenous veins are highly responsive to PGs and PGEA. These data suggest that these substances could influence venous tone in vivo. However, PG-induced changes in venous tone would depend on which PG or intermediate was present, on PG concentration, and on the prior state of venous tone.