CCK receptors-related signaling involved in nitric oxide production caused by gastrin 17 in porcine coronary endothelial cells

In anesthetized pigs gastrin-17 increased coronary blood flow through CCK1/CCK2 receptors and β ₂-adrenoceptors-related nitric oxide (NO) release. Since the intracellular pathway has not been investigated the purpose of this study was to examine in coronary endothelial cells the CCK1/CCK2 receptors-related signaling involved in the effects of gastrin-17 on NO release. Gastrin-17 caused a concentration-dependent increase of NO production (17.3-62.6%; p<0.05), which was augmented by CCK1/CCK2 receptors agonists (p<0.05). The effect of gastrin-17 was amplified by the adenylyl-cyclase activator and β ₂-adrenoceptors agonist (p<0.05), abolished by cAMP/PKA and β ₂-adrenoceptors and CCK1/CCK2 receptors blockers, and reduced by PLC/PKC inhibitor. Finally, Western-blot revealed the preferential involvement of PKA vs. PKC as downstream effectors of CCK1/CCK2 receptors activation leading to Akt, ERK, p38 and endothelial NOS (eNOS) phosphorylation. In conclusion, in coronary endothelial cells, gastrin-17 induced eNOS-dependent NO production through CCK1/CCK2 receptors- and β ₂-adrenoceptors-related pathway. The intracellular signaling involved a preferential PKA pathway over PKC.