Cultured endothelial cells from distinct vascular areas show differential responses to agonists

We compared the ability of cultured endothelial cells isolated from rabbit aorta, vena cava, ventricular chamber, and pulmonary microvasculature to produce relaxing factor(s) in response to acetylcholine (ACh) and bradykinin (BK). Endothelium-denuded rabbit aortic rings were precontracted with 1 microM phenylephrine and superfused at 2 mL/min with Krebs-Henseleit bicarbonate buffer. Rings were exposed to 3-mL bolus control challenges of 1 microM ACh or 1 microM BK. Boluses of ACh or BK were added to dishes of cultured endothelial cells that had been incubated for 45 min in media either with or without 10 microM NG-nitro-L-arginine (NNLA). The resulting solution was applied over the rings within 8 s. Only left ventricular endothelial cells stimulated with ACh and BK, and pulmonary microvascular endothelial cells stimulated with BK produced products that relaxed rings by approximately 6 +/- 2%. Incubation with NNLA attenuated these relaxations. Our findings indicate there are differences in the abilities of endothelial cells of different anatomical origins to release nitric oxide derived relaxing factors in response to ACh and BK.