title: cAMP regulates nitric oxide production and ouabain sensitive Na+, K+-ATPase activity in SH-SY5Y human neuroblastoma cells.
abstract: We investigated the relation between cyclic AMP (cAMP) and nitric oxide (NO) production, as well as the effect of NO on Na , K+-ATPase activity in the human neuroblastoma cell line SH-SY5Y. Two cAMP agonists, dibutyryl cAMP (DBC) and beraprost sodium (BPS), increased cAMP accumulation and NO production in a time and dose dependent manner at 50 mmol/l glucose. On the other hand, cellular sorbitol and myo-inositol contents and protein kinase C activity were not altered by DBC or BPS. A specific protein kinase A inhibitor, H-89, suppressed increases in nitrite/nitrate and cyclic GMP (cGMP) and protein kinase A activity stimulated by DBC or BPS. This finding suggests that cAMP stimulates NO production by activating protein kinase A via a pathway different from the sorbitol-myo-inositol-protein kinase C pathway. We observed that an NO donor, sodium nitroprusside, and an NO agonist, L-arginine, enhanced ouabain sensitive Na+, K+-ATPase activity at 50 mmol/l glucose. We also found that a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), inhibited Na+, K+-ATPase activity at 5 mmol/l glucose, and partially suppressed the enzyme activity stimulated by DBC or BPS. The results of this study suggest that cAMP regulates protein kinase A activity, NO production and ouabain sensitive Na+, K+-ATPase activity in a cascade fashion. The results also suggest that protein kinase A at least partially regulates Na+, K+-ATPase activity without mediation by NO in SH-SY5Y cells. We speculate that cAMP and NO are two important regulatory factors in the pathogenesis of diabetic neuropathy.
authors.affiliation: Third Department of Internal Medicine, Yamanashi Medical University, Tamaho, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Inada
authors.forename: H
authors.initials: H
authors.lastname: Shindo
authors.forename: M
authors.initials: M
authors.lastname: Tawata
authors.forename: T
authors.initials: T
authors.lastname: Onaya
mesh_terms: D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D006152:Cyclic GMP / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011464:Epoprostenol / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D007700:Kinetics; D009447:Neuroblastoma / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000378:metabolism; D010042:Ouabain / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013449:Sulfonamides; D014407:Tumor Cells, Cultured
chemical_list: D004791:Enzyme Inhibitors; D007546:Isoquinolines; D009566:Nitrates; D020030:Nitric Oxide Donors; D009573:Nitrites; D013449:Sulfonamides; D009569:Nitric Oxide; C048081:beraprost; D010042:Ouabain; D003994:Bucladesine; D011464:Epoprostenol; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D017868:Cyclic AMP-Dependent Protein Kinases; D000254:Sodium-Potassium-Exchanging ATPase; D006152:Cyclic GMP; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide