Cyclic CMP and cyclic UMP: new (old) second messengers

Hydrolysis of phosphatidylcholine by phospholipase A2 of synaptic membranes i n Tris-CHl buffer was stimulated by cyclic AMP, cyclic GMP, cyclic CMP, cyclic UMP and adenosine (0.1 mm). In the presence of 1 mm-NaF and cofactors, the same cyclic nucleotides and adenosine (10 mm) stimulated the incorporation of added oleate into the choline glycerophospholipids of synaptic membranes. Cyclic AMP and noradrenaline stimulated the incorporation of added oleate into position 2 of choline glycerophospholipid. Stimulation of net acylation was increased by preincubation in conditions which stimulated hydrolysis of phosphatidylcholine. Cyclic AMP only slightly stimulated the transfer of oleate from oleoyl-CoA into choline glycerophospholipid. The optimum concentration of CaCl2 for the stimulation of hydrolysis by phospholipase A2 by cyclic AMP was 1 mum. Stimulation of the incorporation of added oleate was maximal in the CaCl2 concentration range 1 mum-1mm. MgCl2 also enhanced stimulations, maximum effects being obtained with concentrations of 10 mum and 0.5 mm for hydrolysis by phospholipase A2 and incorporation of added oleate respectively. ATP enhanced the stimulation of incorporation of oleate but had no effect on the cyclic nucleotide stimulation of hydrolysis of added phosphatidylcholine by phospholipase A2. Adenosine, guanosine, ADP and 5′-AMP (all at 1 mm) inhibited the stimulation of incorporation of oleate by cyclic nucleotides and inhibited the transfer of oleate from oleoyl-CoA to phospholipid. They did not inhibit the stimulation of hydrolysis of added phosphatidylcholine (by phospholipase A2) by cyclic nucleotides, but inhibited the stimulation by noradrenaline, acetylcholine, 5-hydroxytryptamine, dopamine (3,4-dihydroxyphenethylamine) and histamine. Preincubation of synaptic membranes in the water or buffer increased the net activity of phospholipase A2. Preincubation with a mixture of ATP and MgCl2 increased the initial rate of acylation of membrane lipid.

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A new tool for investigating the function of the two second messengers of the phosphoinositide system: RHC 80267

Acta Endocrinologica ◽

10.1530/acta.0.117s044-a ◽

1988 ◽

Vol 117 (4_Suppl) ◽

pp. S44-S45

Author(s):

A. PFEIFFER ◽

B. NOELKE ◽

H. ROCHLITZ

Keyword(s):

Second Messengers

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RNA Second Messengers and Riboswitches: Relics from the RNA World?

Microbe Magazine ◽

10.1128/microbe.5.13.1 ◽

2010 ◽

Vol 5 (1) ◽

pp. 13-20 ◽

Cited By ~ 1

Author(s):

Ronald R. Breaker

Keyword(s):

Rna World ◽

Second Messengers

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Sensory Transduction

10.1093/oso/9780198835028.001.0001 ◽

2019 ◽

Cited By ~ 2

Author(s):

Gordon L. Fain

Keyword(s):

Ion Channels ◽

Receptor Cell ◽

Electrical Response ◽

Second Messengers ◽

Sensory Transduction ◽

Sensory Receptor ◽

Signal Pathways ◽

Sense Organs ◽

Sensory Physiology ◽

Effector Molecules

Sensory Transduction provides a thorough and easily accessible introduction to the mechanisms that each of the different kinds of sensory receptor cell uses to convert a sensory stimulus into an electrical response. Beginning with an introduction to methods of experimentation, sensory specializations, ion channels, and G-protein cascades, it provides up-to-date reviews of all of the major senses, including touch, hearing, olfaction, taste, photoreception, and the “extra” senses of thermoreception, electroreception, and magnetoreception. By bringing mechanisms of all of the senses together into a coherent treatment, it facilitates comparison of ion channels, metabotropic effector molecules, second messengers, and other components of signal pathways that are common themes in the physiology of the different sense organs. With its many clear illustrations and easily assimilated exposition, it provides an ideal introduction to current research for the professional in neuroscience, as well as a text for an advanced undergraduate or graduate-level course on sensory physiology.

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Endothelin stimulates chloride secretion across canine tracheal epithelium

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1991.261.2.l188 ◽

1991 ◽

Vol 261 (2) ◽

pp. L188-L194 ◽

Cited By ~ 2

Author(s):

P. I. Plews ◽

Z. A. Abdel-Malek ◽

C. A. Doupnik ◽

G. D. Leikauf

Keyword(s):

Epithelial Cells ◽

Short Circuit ◽

Second Messengers ◽

Short Circuit Current ◽

Chloride Secretion ◽

Tracheal Epithelium ◽

Membrane Phospholipids ◽

Cl Secretion ◽

Tracheal Epithelial Cells ◽

Tracheal Epithelial

The endothelins (ET) are a group of isopeptides produced by a number of cells, including canine tracheal epithelial cells. Because these compounds are endogenous peptides that may activate eicosanoid metabolism, we investigated the effects of ET on Cl secretion in canine tracheal epithelium. Endothelin 1 (ET-1) was found to produce a dose-dependent change in short-circuit current (Isc) that increased slowly and reached a maximal value within 10-15 min. When isopeptides of ET were compared, 300 nM ET-1 and ET-2 produced comparable maximal increases in Isc, whereas ET-3 produced smaller changes in Isc (half-maximal concentrations of 2.2, 7.2, and 10.4 nM, respectively). Ionic substitution of Cl with nontransported anions, iodide and gluconate, reduced ET-1-induced changes in Isc. Furthermore, the response was inhibited by the NaCl cotransport inhibitor, furosemide. In paired tissues, ET-1 significantly increased mucosal net 36Cl flux without significant effect on 22Na flux. The increase in Isc induced by ET was diminished by pretreatment with indomethacin. The second messengers mediating the increase in Isc were investigated in cultured canine tracheal epithelial cells. ET-1 stimulated the release of [3H]arachidonate from membrane phospholipids, increased intracellular Ca2+ (occasionally producing oscillations), and increased adenosine 3',5'-cyclic monophosphate accumulation. The latter was diminished by indomethacin. Thus ET is a potent agonist of Cl secretion (with the isopeptides having the following potency: ET-1 greater than or equal to ET-2 greater than ET-3) and acts, in part, through a cyclooxygenase-dependent mechanism.

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