Influence of primary prostaglandins on isolated canine renal arteries and veins

The sensitivity and contractility of isolated canine renal arteries (RA) and renal veins (RV) to primary prostaglandin compounds (PG) was studied. Studies were also undertaken to determine whether specific receptors for PGs exist in RA and RV.RA and RV exhibited potent concentration-dependent contractile responses to all the primary PGs studied, including PGA₁, PGA₂, PGB₂, PGD₂, PGE₁, PGE₂, PGF_1∝ and PGF_2∝. The contractile sensitivity (based on EC50's) of canine RA to PGs was. PGB₂ > PGB₁ ⋟ PGE₂ > PGF_2∝ ⋟PGA₂ ⋟ PGD₂ ⋟ PGA₁ > PGF_1∝ > PGE₁, whereas for RV it was:PGB₂ > PGB₁ ⋟ PGD2 = PGF_2∝ > PGA₂ = PGA₁ > PGE₂ >>> PGF_1∝ = PGE₁.In terms of the ability to generate a maximum contractile response on RA, PGB₂ was the most potent and PGDthe least potent, whereas for RV PGF_2∝ and PGB₂ was the most potent and PGF_1∝ and PGE the least potent. Canine RA failed to elicit any consistent relaxant responses to PGE₁, PGE₂, PGA₁, and PGA₂. Renal veins, however, in which tone was induced by either PGs or serotonin responded with concentration-related relaxations to PGE₁; other primary PGs did not induce relaxations on isolated RV. Use of specific pharmacologic antagonists (for catecholamines, serotonin, acetylcholine and histamine) failed to interfere with any of the PG responses. The data indicate that RA and RV: a) can exhibit differential responses to primary PGs; b) exhibit structure-activity relationships for the contractile action of PGs; and c) appear to have specific receptors for primary PGs which primarily subserve contraction.