Effects of prostaglandin E2, prostaglandin I2 and 6-keto-prostaglandin F1 alpha on adrenergic neurotransmission in the pulmonary artery of the rabbit.

Strips of the rabbit pulmonary artery were preincubated with 3H-noradrenaline and then superfused and stimulated electrically at 2 or 4 Hz. PGE2 and PGI2 reduced the stimulation-evoked overflow of total tritium and 3H-noradrenaline. PGI2 was about 10 times less potent than PGE2. High concentrations of 6-keto-PGF 1alpha also diminished the evoked overflow, but the effect was small. It is concluded that PGI2, in comparison with PGs of the E series, is a relatively weak inhibitor of noradrenaline release.