title: Characterization of neurotransmitters and dopamine attenuation of inducible nitric oxide synthase in glioma cells.
abstract: Inducible nitric oxide synthase (iNOS) plays a significant role in the pathology of central nervous system diseases. Inducible NOS expression is regulated by intracellular adenosine 3',5'-cyclic monophosphate (cAMP) signaling, and astrocytes contain both iNOS and adenylate cyclase-coupled neurotransmitter receptors. The data obtained from the present study indicated that acetylcholine, lambda-amino-n-butyric acid, glutamate, quinolinic acid, N-methyl-D-aspartate and aspartate have no effect on NO(2)(-) production in C6 glioma cells stimulated by lipopolysaccharide and interferon-gamma. However, dopamine (DA) caused inhibition of NO(2)(-) production and iNOS transcription. The effects of DA were not due to homovanillic acid/3,4-dihydroxyphenylacetic acid, the autoxidative products superoxide (O(2)(-))/hydrogen peroxide (H(2)O(2)) or direct reactions with NO(2)(-). Forskolin, adenylate cyclase activator, dose-dependently reduced NO(2)(-). Meanwhile, (+/-) SKF-38393 D(1) receptor agonist attenuated iNOS in a similar fashion to DA. In addition, the results indicated that DA attenuation of iNOS was significantly impeded by the adenylate cyclase inhibitor MDL-12,330A, the D(1) antagonist SCH-23390, the beta2 adrenergic receptor antagonist ICI-118,551 and the beta1 adrenergic receptor antagonist atenolol. In conclusion, it appears that DA attenuates iNOS through a D(1), beta1 and beta2 adrenergic receptor-linked adenylate cyclase-mediated cAMP cascade.
authors.affiliation: College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Mazzio
authors.forename: Allan
authors.initials: A
authors.lastname: Becker
authors.forename: Karam F A
authors.initials: KF
authors.lastname: Soliman
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000067956:Adenylyl Cyclase Inhibitors; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005910:Glioma; D007097:Imines / Q000494:pharmacology; D009457:Neuroglia / Q000201:enzymology*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000032:analysis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D000319:Adrenergic beta-Antagonists; D004791:Enzyme Inhibitors; D007097:Imines; D018377:Neurotransmitter Agents; D009573:Nitrites; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D005576:Colforsin; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; C014925:RMI 12330A; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D004298:Dopamine