Endothelium-dependent vasodilator actions of acetylcholine, calcium-ionophore (A23187) and substance P in perfused renal arteries from rabbits.

The role of endothelium on the responses of the perfused rabbit renal artery segments to vasoconstrictor and vasodilator agents was studied. The vasoconstrictor responses of rabbit renal arteries to phenylephrine were enhanced by endothelium destruction. Acetylcholine (ACh), calcium-ionophore (A23187) and substance P (SP), in the presence of indomethacin, induced endothelium-dependent vasodilation of the phenylephrine-constricted renal arteries. Nordihydroguaiaretic acid (NDGA), an inhibitor of lipoxygenase, significantly reduced the dilator responses to ACh, A23187 and SP, but did not reduce the responses to sodium nitrite. In conclusion, our results provide evidence for the involvement of lipoxygenase products in the endothelium-dependent vasodilation of rabbit renal arteries to ACh, A23184 and SP.