Opposite regulation of adenylyl cyclase by protein kinase C in astrocyte and microglia cultures. 1997

M Patrizio, and N Slepko, and G Levi
Neurobiology Section, Laboratory of Pathophysiology, Istituto Superiore di Sanità, Rome, Italy.

We studied the regulation of cyclic AMP responses by protein kinase C (PKC) in purified astrocyte and microglia cultures obtained from the neonatal rat brain. In astrocytes, a 10-min treatment with the phorbol esters phorbol 12-myristate 13-acetate (PMA) and 4beta-phorbol 12,13-didecanoate (4beta-PDD) (but not with 4alpha-PDD) or with diacylglycerol, which activate PKC, dose-dependently enhanced cyclic AMP accumulation induced by the beta-adrenergic agonist isoproterenol and the adenylyl cyclase activator forskolin. Such enhancement was prevented by the PKC inhibitors staurosporine and calphostin-C and by down-regulation of PKC and was not related to activation of membrane receptors or Gs proteins or to inhibition of Gi proteins or phosphodiesterases. Instead, the activity of adenylyl cyclase doubled in PMA-treated astrocytes. In microglia, a 10-min treatment with PMA or PKC inhibitors did not affect cyclic AMP accumulation, whereas longer treatments with PMA or 4beta-PDD (but not 4alpha-PDD) inhibited the cyclic AMP response in a time- and dose-dependent manner. Such inhibition was mimicked by staurosporine and calphostin-C. Also, in the case of microglia, the modulation of cyclic AMP responses appeared to occur at the level of adenylyl cyclase, and not elsewhere in the cyclic AMP cascade. The inhibition of microglial adenylyl cyclase was apparently not due to aspecific cytotoxicity. A differential regulation of adenylyl cyclase by PKC in astrocytes and microglia may help to explain qualitative and quantitative differences in the response of these cells to various physiological and pathological stimuli.

UI MeSH Term Description Entries
D007545 Isoproterenol Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant. Isoprenaline,Isopropylarterenol,4-(1-Hydroxy-2-((1-methylethyl)amino)ethyl)-1,2-benzenediol,Euspiran,Isadrin,Isadrine,Isopropyl Noradrenaline,Isopropylnoradrenaline,Isopropylnorepinephrine,Isoproterenol Hydrochloride,Isoproterenol Sulfate,Isuprel,Izadrin,Norisodrine,Novodrin,Hydrochloride, Isoproterenol,Noradrenaline, Isopropyl,Sulfate, Isoproterenol
D007700 Kinetics The rate dynamics in chemical or physical systems.
D009281 Naphthalenes Two-ring crystalline hydrocarbons isolated from coal tar. They are used as intermediates in chemical synthesis, as insect repellents, fungicides, lubricants, preservatives, and, formerly, as topical antiseptics.
D011493 Protein Kinase C An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters. Calcium Phospholipid-Dependent Protein Kinase,Calcium-Activated Phospholipid-Dependent Kinase,PKC Serine-Threonine Kinase,Phospholipid-Sensitive Calcium-Dependent Protein Kinase,Protein Kinase M,Calcium Activated Phospholipid Dependent Kinase,Calcium Phospholipid Dependent Protein Kinase,PKC Serine Threonine Kinase,Phospholipid Sensitive Calcium Dependent Protein Kinase,Phospholipid-Dependent Kinase, Calcium-Activated,Serine-Threonine Kinase, PKC
D002462 Cell Membrane The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells. Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
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
D002540 Cerebral Cortex The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions. Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D003600 Cytosol Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components. Cytosols
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
D005576 Colforsin Potent activator of the adenylate cyclase system and the biosynthesis of cyclic AMP. From the plant COLEUS FORSKOHLII. Has antihypertensive, positive inotropic, platelet aggregation inhibitory, and smooth muscle relaxant activities; also lowers intraocular pressure and promotes release of hormones from the pituitary gland. Coleonol,Forskolin,N,N-Dimethyl-beta-alanine-5-(acetyloxy)-3-ethenyldodecahydro-10,10b-dihydroxy-3,4a,7,7,10a-pentamethyl-1-oxo-1H-naphtho(2,1-b)pyran-6-yl Ester HCl,NKH 477,NKH-477,NKH477

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