Inducible nitric oxide synthase expression in activated rat microglial cultures is downregulated by exogenous prostaglandin E2 and by cyclooxygenase inhibitors. 1997

L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
Neurobiology Section, Istituto Superiore di Sanità, Rome, Italy.

Prostaglandins and nitric oxide (NO) are among the numerous substances released by activated microglial cells, the brain resident macrophages, and they mediate several important microglial functions. We have previously shown that cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS), the two key enzymes in prostaglandin and NO synthesis, respectively, are rapidly co-induced in rat neonatal microglial cultures activated by bacterial endotoxin (lipopolysaccharide [LPS]) and that COX-2 expression appears to be under the negative control of endogenous as well as exogenous NO. In this study we show that exogenous prostaglandin E2 (PGE2), which is known to increase cyclic adenosine monophosphate (cAMP) levels in microglial cells, downregulates LPS-induced iNOS expression in a dose-dependent manner. The involvement of cAMP in the PGE2-dependent inhibition of iNOS is supported by several pieces of evidence. First, iNOS expression was also inhibited by agents such as isoproterenol and forskolin, which cause an elevation of cAMP levels, and by dibutyryl cAMP (dbcAMP), a cAMP stable analogue. Second, the inhibitory effect of PGE2 was mimicked by 11-deoxy-16,16-dm PGE2, a selective agonist at the PGE2 receptor subtype EP2, coupled to the activation of adenylyl cyclase, but not by sulprostone, a potent agonist at receptor subtypes EP3 and EP1, associated with an inhibition of adenylyl cyclase activity and intracellular Ca2+ elevation, respectively. Third, the inhibitory effect of PGE2 on NO synthesis was blocked by SQ 22,536, a specific inhibitor of adenylyl cyclase. Interestingly, the abrogation of endogenous prostanoid production by several COX inhibitors caused a reduction of iNOS expression, suggesting a positive modulatory effect of endogenous prostanoids of iNOS expression, as opposed to the inhibitory effect of exogenous PGE2.

UI MeSH Term Description Entries
D008070 Lipopolysaccharides Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed) Lipopolysaccharide,Lipoglycans
D008600 Menstruation-Inducing Agents Chemical compounds that induce menstruation either through direct action on the reproductive organs or through indirect action by relieving another condition of which amenorrhea is a secondary result. (From Dorland, 27th ed) Emmenagogues,Menstruation Inducing Agents
D008969 Molecular Sequence Data Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories. Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D011982 Receptors, Prostaglandin Cell surface receptors that bind prostaglandins with high affinity and trigger intracellular changes which influence the behavior of cells. Prostaglandin receptor subtypes have been tentatively named according to their relative affinities for the endogenous prostaglandins. They include those which prefer prostaglandin D2 (DP receptors), prostaglandin E2 (EP1, EP2, and EP3 receptors), prostaglandin F2-alpha (FP receptors), and prostacyclin (IP receptors). Prostaglandin Receptors,Prostaglandin Receptor,Receptor, Prostaglandin,Receptors, Prostaglandins,Prostaglandins Receptors
D002478 Cells, Cultured Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others. Cultured Cells,Cell, Cultured,Cultured Cell
D003994 Bucladesine A cyclic nucleotide derivative that mimics the action of endogenous CYCLIC AMP and is capable of permeating the cell membrane. It has vasodilator properties and is used as a cardiac stimulant. (From Merck Index, 11th ed) Dibutyryl Adenosine-3',5'-Monophosphate,Dibutyryl Cyclic AMP,(But)(2) cAMP,Bucladesine, Barium (1:1) Salt,Bucladesine, Disodium Salt,Bucladesine, Monosodium Salt,Bucladesine, Sodium Salt,DBcAMP,Dibutyryl Adenosine 3,5 Monophosphate,N',O'-Dibutyryl-cAMP,N(6),0(2')-Dibutyryl Cyclic AMP,AMP, Dibutyryl Cyclic,Adenosine-3',5'-Monophosphate, Dibutyryl,Cyclic AMP, Dibutyryl,Dibutyryl Adenosine 3',5' Monophosphate,Disodium Salt Bucladesine,Monosodium Salt Bucladesine,N',O' Dibutyryl cAMP,Sodium Salt Bucladesine
D004791 Enzyme Inhibitors Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D000067956 Adenylyl Cyclase Inhibitors Compounds that bind to and inhibit the action of ADENYLYL CYCLASES. Adenylate Cyclase Inhibitors,Cyclase Inhibitors, Adenylate,Cyclase Inhibitors, Adenylyl,Inhibitors, Adenylate Cyclase,Inhibitors, Adenylyl Cyclase
D000225 Adenine A purine base and a fundamental unit of ADENINE NUCLEOTIDES. Vitamin B 4,4, Vitamin B,B 4, Vitamin
D000242 Cyclic AMP An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH. Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic

Related Publications

L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
August 1998, Brain research. Molecular brain research,
L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
September 2008, Archives of biochemistry and biophysics,
L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
January 1995, Advances in pharmacology (San Diego, Calif.),
L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
December 2000, Comparative biochemistry and physiology. Toxicology & pharmacology : CBP,
L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
February 1997, Biochemical pharmacology,
L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
November 2014, Pharmaceutical biology,
L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
March 1995, The American journal of physiology,
L Minghetti, and A Nicolini, and E Polazzi, and C Créminon, and J Maclouf, and G Levi
January 2001, Proceedings of the Western Pharmacology Society,
Copied contents to your clipboard!