Stimulation of cyclic GMP production in cultured endothelial cells of the pig by bradykinin, adenosine diphosphate, calcium ionophore A23187 and nitric oxide

Open Access
Publisher Website
Google Scholar
Abstract
1 The effects of bradykinin, adenosine diphosphate, calcium ionophore A23187 and nitric oxide on the production of adenosine 3′:5′-cyclic monophosphate (cyclic AMP) and guanosine 3′:5′-cyclic monophosphate (cyclic GMP) were investigated in cultured aortic endothelial cells of the pig. 2 Bradykinin (10−7m), adenosine diphosphate (3 × 10−5m), nitric oxide (2 × 10−6m) and A23187 (10−6m) stimulated the production of cyclic GMP. This stimulation reached a maximum within 1 min and declined rapidly with the first three agonists whereas that induced by A23187 was long-lasting. 3 These concentrations of bradykinin, A23187 and nitric oxide had no effect on cyclic AMP production. However, adenosine diphosphate (3 × 10−5m) slightly but significantly enhanced its production by about 1.7 fold. 4 The basal content of cyclic GMP in endothelial cells was significantly reduced by haemoglobin (10−5m, a scavenger of endothelium-derived relaxing factor(s) and methylene blue (10−5m, an inhibitor of the activation of soluble guanylate cyclase) and was significantly enhanced by superoxide dismutase (500 u ml−1, a scavenger of superoxide anions). The basal content of cyclic GMP was not affected by NG-monomethyl-l-arginine (10−5m, a specific inhibitor of the formation of nitric oxide from l-arginine) and was slightly but significantly increased by its d-enantiomer, NG-monomethyl-d-arginine. 5 The production of cyclic GMP stimulated by bradykinin, adenosine diphosphate, A23187 and nitric oxide was inhibited by haemoglobin (10−5m) and methylene blue (10−5m) but was unaffected by superoxide dismutase (500 u ml−1). 6 The production of cyclic GMP stimulated by bradykinin, adenosine diphosphate or A23187, but not that stimulated by nitric oxide, was significantly reduced by NG-monomethyl-l-arginine (10−5m). The production of cyclic GMP evoked by nitric oxide, but not that induced by the other three agents, was enhanced significantly by NG-monomethyl-d-arginine by about 1.5 fold. 7 These data indicate that the endothelium-dependent vasodilators bradykinin, adenosine diphosphate and A23187 activate the production of cyclic GMP in endothelial cells via the synthesis of nitric oxide, which in turn stimulates the soluble guanylate cyclase.