Effect of verapamil on the pulmonary vasoconstrictor action of prostaglandin F2 alpha and a synthetic PGH2 analogue.

1 The vasopressor response to prostaglandin F2 alpha (PGF2 alpha) and to ((15S)-hydroxy-11 alpha, 9 alpha-(epoxymethano)-prosta-5Z, 13E-dienoic acid) (U-46619) in the canine isolated lung lobe was significantly attenuated following the administration of verapamil. 2 The pressor response to arachidonic acid (AA) was not affected by the presence of verapamil. 3 The pulmonary pressor effect of PGF2 alpha and U-46619 is dependent, at least in part, on Ca2+ influx into vascular smooth muscle cells. 4 The pulmonary pressor response to AA cannot be attributed to PGF2 alpha or to endoperoxide intermediates but to some other product dependent on intracellular calcium stores.