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Kimura M, Lasker N, Aviv A. Cyclic nucleotides attenuate thrombin-evoked alterations in parameters of platelet Na/H antiport. The role of cytosolic Ca. J Clin Invest 1992; 89:1121-7. [PMID: 1313446 PMCID: PMC442968 DOI: 10.1172/jci115692] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In this work, we explored the role of cyclic nucleotides in modulating parameters of the Na/H antiport in human platelets. Sodium nitroprusside and iloprost, as well as cyclic nucleotide analogues, were used to raise cellular levels of cAMP and cGMP. Cyclic nucleotides reversed the thrombin-evoked alkaline shift in cytosolic pH set point and the activity of the Na/H antiport, concurrently with attenuation of thrombin-induced rise in cytosolic free Ca. No effect of cyclic nucleotides was observed in platelets not treated with thrombin, or platelets subjected to phorbol 12-myristate 13-acetate. cAMP did not reverse ionomycin-induced changes in the parameters of the Na/H antiport. Collectively, these observations indicate that cyclic nucleotides modulate the Na/H antiporter in human platelets through their effect on thrombin-evoked changes in cytosolic free Ca. Presumably, this effect holds for other agonists which stimulate phospholipase C, raise cytosolic-free Ca, and activate the Na/H antiport through protein kinase C dependent and protein kinase C-independent mechanisms.
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127
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Vaillier D, Daculsi R, Gualde N, Bezian JH. Effect of LTB4 on the inhibition of natural cytotoxic activity by PGE2. Cell Immunol 1992; 139:248-58. [PMID: 1309490 DOI: 10.1016/0008-8749(92)90117-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
NK activity is regulated by arachidonic acid metabolites. More precisely PGE2 and LTB4 decreases and increases respectively non-MHC-restricted cytotoxicity in humans. We have observed similar data in mice since NK activity was inhibited by PGE2 (10(-6) to 10(-8) M) and enhanced by LTB4 (10(-8) to 10(-12) M). On the other hand when PGE2 and LTB4 were combined during the same assay the lysis percentage was smaller than the one which was induced by PGE2 alone. Because PGE2 increases intracellular cyclic AMP and that LTB4 augments cyclic GMP we used a cAMP inducer (forskolin) and a cGMP analogue (8 Br-cGMP) instead of eicosanoids and we observed similar data (i.e., a decrease of natural killing) as when PGE2 was combined with LTB4. When splenocytes are cultured for 1-4 days alone, cytotoxic activity decreases unless they are cultured in the presence of indomethacin. Cytotoxic activity of spleen cells cultured in the presence of PGE2 or LTB4 is respectively decreased or increased. However, splenocytes that were cultured alone for at least 24 hr were no longer sensitive to inhibition by PGE2 but were still PGE2-sensitive when cultured in the presence of LTB4.
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128
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Kaupp UB, Altenhofen W. Cyclic nucleotide-gated channels of vertebrate photoreceptor cells and olfactory epithelium. SOCIETY OF GENERAL PHYSIOLOGISTS SERIES 1992; 47:133-50. [PMID: 1369759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
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129
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Firestein S. Physiology of transduction in the single olfactory sensory neuron. SOCIETY OF GENERAL PHYSIOLOGISTS SERIES 1992; 47:61-71. [PMID: 1369775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
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130
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Shepherd GM. Toward a consensus working model for olfactory transduction. SOCIETY OF GENERAL PHYSIOLOGISTS SERIES 1992; 47:19-37. [PMID: 1369762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
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131
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Heaton JH, Kathju S, Gelehrter TD. Transcriptional and posttranscriptional regulation of type 1 plasminogen activator inhibitor and tissue-type plasminogen activator gene expression in HTC rat hepatoma cells by glucocorticoids and cyclic nucleotides. Mol Endocrinol 1992; 6:53-60. [PMID: 1738371 DOI: 10.1210/mend.6.1.1738371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have reported previously that incubation of HTC rat hepatoma cells with the synthetic glucocorticoid dexamethasone causes a 90% decrease in tissue-type plasminogen activator (tPA) activity secondary to a 4-fold increase in plasminogen activator inhibitor-1 (PAI-1) mRNA accumulation. Dexamethasone also induces a modest and transient increase in tPA mRNA. The cyclic nucleotide analog 8-bromo-cAMP (cA) causes a greater than 50-fold increase in PA activity, the result of a 90% decrease in PAI-1 and a sustained 2-fold increase in tPA mRNA accumulation. Dexamethasone and cA in combination cause a 150-fold increase in PA activity, the result of an 80% decrease in PAI-1 and a synergistic 15-fold increase in tPA mRNA. To determine the mechanism of this complex hormonal regulation, we have examined rates of synthesis and decay of PAI-1 and tPA mRNAs. Here we report that dexamethasone induces a 5-fold increase in PAI-1 gene transcription and does not significantly alter PAI-1 message decay; PAI-1 mRNA has a half-life of about 4 h in both untreated and dexamethasone-treated cells. In contrast, cA regulates PAI-1 mRNA by both decreasing the rate of PAI-1 gene transcription by 60% and accelerating the rate of PAI-1 message decay. Regulation of tPA by cA, both alone and in combination with dexamethasone, occurs primarily at the level of transcription. Dexamethasone and cA-induced tPA mRNA has a half-life of 2.75 h; tPA mRNA degradation is significantly inhibited by either cycloheximide or actinomycin-D.(ABSTRACT TRUNCATED AT 250 WORDS)
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132
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Firestein S, Zufall F, Shepherd GM. Single odor-sensitive channels in olfactory receptor neurons are also gated by cyclic nucleotides. J Neurosci 1991; 11:3565-72. [PMID: 1719165 PMCID: PMC6575548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Olfactory transduction is thought to occur by processes that are mainly restricted to the specialized cilia emanating from the distal end of the receptor neuron's single dendrite. The involvement of a cAMP-based second messenger system seems likely, and a cyclic nucleotide-sensitive current has been recorded in patches of membrane from the cilia. However, the small diameter of the cilia and the high density of channels within the membrane limit the application of the patch recording technique in the cilia. We have found that the cAMP-sensitive channels also exist at a much lower density within the far more accessible dendritic membrane. Recording from on-cell patches, we have observed single-channel activity in response to extracellularly applied odor substances. The channels have a single-channel conductance of 40 pS and a reversal potential near 0 mV. These same channels are activated by treatments that elevate intracellular cyclic nucleotide concentrations. The results provide a direct demonstration that the cyclic nucleotide-gated channel is the conductance pathway for the odor-elicited current.
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133
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Zufall F, Firestein S, Shepherd GM. Analysis of single cyclic nucleotide-gated channels in olfactory receptor cells. J Neurosci 1991; 11:3573-80. [PMID: 1719166 PMCID: PMC6575547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In the accompanying article (Firestein et al., 1991b), we have demonstrated that odor- and cyclic nucleotide-sensitive channels exist at a low density in the dendritic membranes of isolated salamander olfactory receptor neurons. Here, we analyze the cyclic nucleotide sensitivity of these channels using the inside-out patch recording technique. Both cAMP and cGMP, at micromolar concentrations, are capable of inducing channel openings. The biophysical parameters of channel activity are nearly the same in response to either ligand. The unitary conductance is about 45 pS, the reversal potential of single-channel currents is +5 mV, and the I/V relation is linear over the range -80 to +80 mV. The channel activity shows no obvious voltage dependence in divalent cation-free symmetrical solutions. The channel shows no desensitization, even to agonist exposures lasting 15 sec. Mean open time is about 1.5 msec; the closed time distribution is best fit by two exponentials with a fast time constant in the submillisecond range (ca. 0.15 msec) and a slower time constant in the millisecond range (ca. 1.5 msec). The only clear difference in the activity of the two ligands is in their affinity constants. The K1/2 for cAMP is 20 microM; that for cGMP is 4 microM. In both cases, the Hill coefficient is greater than 2, suggesting that channel opening requires the cooperative action of three ligand molecules.
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134
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Rodriguez A, Sainz De La Maza M, Missry J, Foster CS. The role of cyclic nucleotide mediators in latency and reactivation of HSV-1 infected neuroblastoma cells. Eye (Lond) 1991; 5 ( Pt 5):627-35. [PMID: 1665422 DOI: 10.1038/eye.1991.109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The mechanisms that control herpes simplex virus type 1 latency and reactivation are still poorly understood. We developed an in vitro murine neuroblastoma cell HSV-infected, acyclovir suppressed model to study the influence of different cyclic nucleotide mediators on the latency and reactivation of HSV-1. A positive cDNA 'in situ' hybridisation for HSV genome was used to prove the establishment of a viral-host cell nuclear relationship. An ABC-immunoperoxidase reaction to cell surface HSV mature glycoproteins was also performed to determine the time of viral reactivation with formation of mature virions. Supernates of cultured cells were placed on Vero cells for confirmation of reactivation by classic cytopathic effect. Theophylline (50 micrograms/ml) and dibutyryl-cAMP (0.1, 0.5, 1 mg/ml) produced the most pronounced response, accelerating HSV reactivation time by 150%. Epinephrine (10, 20 micrograms/ml) had an intermediate effect on accelerating viral reactivation; and verapamil (20, 50 micrograms/ml), theophylline and epinephrine at lower doses had a smaller effect. Carbamylcholine (10 micrograms/ml) prolonged the time to viral reactivation by 100%, 36 hours compared to control time of 18 hours. Insulin (0.1, 0.5, 1 mg/ml) also prolonged HSV 'latency' by six hours. Exogenous dibutyryl-cGMP and carbamylcholine at lower concentrations did not have an effect on viral reactivation. These findings suggest that there is a relationship between changes of intracellular concentration of cyclic nucleotides and HSV latency and reactivation.
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135
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Khan I, Grover AK. Expression of cyclic-nucleotide-sensitive and -insensitive isoforms of the plasma membrane Ca2+ pump in smooth muscle and other tissues. Biochem J 1991; 277 ( Pt 2):345-9. [PMID: 1830473 PMCID: PMC1151240 DOI: 10.1042/bj2770345] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
cDNA clones encoding the plasma membrane Ca2+ pump isoform PMCA1 were obtained from rabbit stomach smooth muscle. The PMCA1 gene has a 154 base exon which can be alternatively spliced. In splices containing 0, 87 or 114 bases of this exon, the mRNA downstream from this position encodes a protein containing the peptide sequence Lys-Arg-Asn-Ser-Ser (KRNSS), which can be phosphorylated by cyclic-nucleotide-sensitive protein kinase. However, in those splices containing 154 bases, the mRNA encodes a protein that does not contain this sequence. The cDNA clone obtained in this study did not contain the latter exon, and thus it coded for KRNSS. The presence of the various splices of PMCA1 was determined in stomach smooth muscle and other tissues by reverse transcription followed by a polymerase chain reaction. Percentage of transcripts encoding the potentially cyclic-nucleotide-sensitive isoform in various tissues were as follows: liver, 100%; stomach mucosa, 100%; heart, 100%; stomach smooth muscle, 86%; aorta, 83%; brain, 55%. Thus brain was the only tissue which expressed a very high proportion of the isoform of PMCA1 that is insensitive to cyclic-nucleotide-dependent protein kinases.
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136
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Samoĭlov VO, Ponomarenko GN. [Role of cyclic nucleotides in carotid chemoreception]. BIULLETEN' EKSPERIMENTAL'NOI BIOLOGII I MEDITSINY 1991; 111:610-2. [PMID: 1654163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The activation of the metabolic systems of rat carotid body under the influence of alkaloids and acids was studied by spectrofluorimetric technique. It has been demonstrated the growth of the cAMR levels being suggested to the role of messenger between chemical stimuli and the flows of glomus cells metabolism. Chemical substances of other types (such as acetylcholine, NaCl saccharose) don't provide any changes of cell respiration and concentration of cAMP in carotid cells. The data obtained provide the evidence of heterogeneity of glomus cella reception mechanisms of the qualitatively different chemical substances. It supports the hypothesis on the heterogeneity of chemoreception for mammals.
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137
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Kaupp UB. The cyclic nucleotide-gated channels of vertebrate photoreceptors and olfactory epithelium. Trends Neurosci 1991; 14:150-7. [PMID: 1710853 DOI: 10.1016/0166-2236(91)90087-b] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cation channels that are directly gated by guanosine 3', 5'-cyclic monophosphate (cGMP) control the flow of ions across the surface membrane of vertebrate rod and cone photoreceptor cells. A similar channel, gated by adenosine 3',5'-cyclic monophosphate (cAMP), exists in vertebrate olfactory sensory neurons. The channel polypeptide of rod photoreceptors has been identified and the amino acid sequence of the channel polypeptide in rod and olfactory cells has been determined by cloning cDNA. Although the cyclic nucleotide-gated channels functionally belong to the class of ligand-gated channels, they share some structural features with voltage-gated channels.
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138
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Pasechnikov VD, Virganskiĭ LO. [The role of cyclic nucleotides in adaptation of the gastric mucosa to hypoxia]. VOPROSY MEDITSINSKOI KHIMII 1991; 37:61-2. [PMID: 1897199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
State of oxygen consumption in gastric mucosal membrane evaluated by means of pO2 measurement as well as metabolism of cyclic nucleotides were studied in patients with ulcerous disease. Hypoxia of periulcerous area and alterations in functional activity of the cyclase systems were detected. Reciprocal alterations in the cyclases activity, as a result of which the ratio of cyclic nucleotides was changed under dissimilar conditions of oxygen consumption in gastric mucosal membrane, were considered as essential adaptive reaction related to maintenance of proliferation under conditions of oxygen and energy rich substances deficiency.
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139
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Hoger JH, Walter AE, Vance D, Yu L, Lester HA, Davidson N. Modulation of a cloned mouse brain potassium channel. Neuron 1991; 6:227-36. [PMID: 1899581 DOI: 10.1016/0896-6273(91)90358-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The mouse brain K+ channel (MBK), previously cloned by others, has been independently cloned and shown to express in Xenopus oocytes. This K+ current (IK) inactivated over a time course of seconds and was sensitive to the K+ channel-blocking reagent tetraethylammonium. When the K+ channel was coexpressed with a cloned mouse brain serotonin receptor (5HT1c) in oocytes, activation of the 5HT1c receptor by a brief application of serotonin resulted in a suppression of the IK amplitude over the next 20 min. IK could also be suppressed by activation of G proteins. Suppression was also caused by intracellular Ca2+ injections and was blocked by intracellular injection of EGTA. Calmodulin antagonists block the IK suppression, but a known protein kinase inhibitor did not block suppression. The 5HT1c suppression was reversible; recovery from suppression was blocked by the protein kinase inhibitor H-7. These data suggest that the IK suppression occurs through a novel mechanism independent of A- or C-type protein kinases; suppression is best explained as being due to the action of a Ca2+/calmodulin-activated phosphatase; recovery from suppression is due to the action of a protein kinase.
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140
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Rosen EM, Jaken S, Carley W, Luckett PM, Setter E, Bhargava M, Goldberg ID. Regulation of motility in bovine brain endothelial cells. J Cell Physiol 1991; 146:325-35. [PMID: 1825664 DOI: 10.1002/jcp.1041460218] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Scatter factor (SF) is a fibroblast-derived cytokine which stimulates motility of epithelial and vascular endothelial cells. We used a quantitative assay based on migration of cells from microcarrier beads to flat surfaces to study the regulation of motility in bovine brain endothelial cells (BBEC). Peptide growth factors (EGF, ECGF, basic FGF) did not stimulate migration. Tumor promoting phorbol esters (PMA, PDD) markedly stimulated migration, while inactive phorbol esters (4a-PDD, phorbol-13,20-diacetate) did not affect migration. Both SF- and PMA-stimulated migration were inhibited by 1) TGF-beta; 2) protein kinase inhibitors (e.g., staurosporine, K-252a); 3) activators of the adenylate cyclase signaling pathway (e.g., dibutyryl cyclic AMP, theophylline); 4) cycloheximide; and 5) anti-cytoskeleton agents (e.g., cytochalasin B, colcemid). However, PMA and SF pathways were distinguishable: 1) PMA induced additional migration at saturating SF concentrations; 2) the onset of migration-stimulation was immediate for PMA and delayed for SF; and 3) down-modulation of protein kinase C (PKC) ablated PMA but not SF responsiveness. Assessment of PKC by (3H)-phorbol ester (PDBu) binding and by immunoblot showed 1) scatter factor does not cause significant redistribution or down-modulation of PDBu binding or alpha-PKC; and 2) PDBu mediates redistribution and down-modulation of both binding and alpha-PKC. These findings suggest two pathways for BBEC motility: a PKC-dependent pathway and an SF-stimulated/PKC-independent pathway.
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141
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Endres S, Fülle HJ, Sinha B, Stoll D, Dinarello CA, Gerzer R, Weber PC. Cyclic nucleotides differentially regulate the synthesis of tumour necrosis factor-alpha and interleukin-1 beta by human mononuclear cells. Immunology 1991; 72:56-60. [PMID: 1847694 PMCID: PMC1384335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Recent reports have shown that phosphodiesterase (PDE) inhibitors suppress production of tumour necrosis factor-alpha (TNF-alpha) in mouse macrophages. In the present study we show that theophylline, pentoxifylline and 3-isobutyl-1-methylxanthine markedly suppress the lipopolysaccharide (LPS)-induced synthesis of TNF-alpha (also) in human mononuclear cells. This effect is selective for TNF-alpha since up to several-fold higher concentrations of these PDE inhibitors do not affect production of interleukin-1 beta (IL-1 beta) in the same system. The observed effect of PDE inhibitors appears to be mediated by accumulation of cAMP since (i) addition of PDE inhibitors increases cAMP while cGMP levels are only marginally elevated; (ii) raising cAMP by another mechanism (enhanced formation induced by prostaglandin E2; PGE2) leads to a similar suppression of TNF-alpha production; and (iii) raising cGMP by activating the soluble guanylate cyclase by 3-morpholinosydnonimine (SIN 1) does not inhibit TNF-alpha synthesis. However, SIN 1 suppressed the synthesis of IL-1 beta. Selective suppression of TNF-alpha synthesis by PDE inhibitors may contribute to their beneficial effects in animal models of septic shock or lung injury and may thus have clinical implications.
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142
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Seglen PO, Gordon PB, Holen I. Non-selective autophagy. SEMINARS IN CELL BIOLOGY 1990; 1:441-8. [PMID: 2103895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Autophagy is the major process by which cells degrade their own cytoplasm. Autophagy begins with the sequestration of a portion of the cytoplasm by a membraneous organelle called a phagophore. The resulting vacuole (autophagosome) can fuse with an endocytic vacuole to form am amphisome, which subsequently fuses with a lysosome to have its mixed autophagic/endocytic content degraded by lysosomal enzymes. Autophagy is a non-selective bulk process as indicated by the fact that hepatocytic cytosol enzymes with widely different half-lives are sequestered at the same rate. Regulation of autophagy is exerted at the sequestration step by amino acids, purines, ATP-depleting metabolites, cyclic nucleotides, phosphorylation, and hormones like insulin, glucagon and alpha-adrenergic agonists.
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143
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Randriamampita C, Trautmann A. Arachidonic acid activates Ca2+ extrusion in macrophages. J Biol Chem 1990; 265:18059-62. [PMID: 2145278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Stimulation of macrophages with platelet-activating factor (PAF) elicits an increase of intracellular calcium concentration, Ca2+i, which was monitored here at the single cell level with the calcium-sensitive dye Fura-2. The sustained component of this Ca2+i increase reflects the dynamic balance achieved between enhanced Ca2+ influx and efflux. In macrophages where a steady increase of Ca2+i has been evoked by 50 nM thapsigargin (a molecule known to empty Ca2+ stores and elevate Ca2+i in various cell types), PAF activates Ca2+ efflux, without causing a preceding increase in Ca2+i. This result shows that in this case, Ca2+ extrusion is not merely a consequence of a Ca2+i increase. PAF-evoked Ca2+ extrusion does not result from the activation of the Na+/Ca2+ exchanger. Exogenous arachidonic acid (10-100 microM) elicits Ca2+ efflux in macrophages where Ca2+i has been previously elevated by either PAF or thapsigargin. PAF-induced Ca2+ extrusion is blocked by 4-bromophenacylbromide, an inhibitor of arachidonic acid production by phospholipase A2. Together, these results suggest that arachidonic acid, which is produced in PAF-stimulated macrophages, contributes to the regulation of a Ca2+ extrusion system, which is presumably a Ca2(+)-ATPase.
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144
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Serbeniuk TV, Lelekova TV. [The effect of cyclic nucleotides on the rhythmogenicity of the lymphatic center in the frog Rana temporaria]. ZHURNAL EVOLIUTSIONNOI BIOKHIMII I FIZIOLOGII 1990; 26:680-7. [PMID: 1708937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Studies have been made of the effect of cAMP on the spontaneous impulse activity of lymphatic pacemaker neurons in the frog. It was shown that inhibition of phosphodiesterases by papaverine and 3-isobutyl-1-methylxanthin resulted in the increase in rhythm of bursting impulse activity of the lymphatic centre turning it into a continuous one. The same effect was produced by dibutyryl-cAMP, and to a lower extent--by cAMP. CGMP blocked rhythmic activity of the centre. Possible role of cyclic nucleotides in rhythmic activity of pacemaker cells in the spinal centre of the lymphatic hearts in the frog is discussed.
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145
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Smirnov VN, Voyno-Yasenetskaya TA, Antonov AS, Lukashev ME, Shirinsky VP, Tertov VV, Tkachuk VA. Vascular signal transduction and atherosclerosis. Ann N Y Acad Sci 1990; 598:167-81. [PMID: 2248435 DOI: 10.1111/j.1749-6632.1990.tb42288.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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146
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Kolesnikov SS, Zhainazarov AB, Kosolapov AV. Cyclic nucleotide-activated channels in the frog olfactory receptor plasma membrane. FEBS Lett 1990; 266:96-8. [PMID: 1694788 DOI: 10.1016/0014-5793(90)81515-p] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Patch clamp technique was used to record cyclic nucleotide-dependent current of the frog olfactory receptor cell plasma membrane. Data obtained indicate that the channels passing this current are permeable to Ca2+ or Mg2+ and moderately selective for monovalent cations according to the sequence Li+, Na+, K+ greater than Rb+ greater than Cs+ and are effectively blocked by 1-cis-diltiazem and 3',4'-dichlorobenzamil. The conductance of single cyclic nucleotide-gated channels in solutions with low Ca2+ and Mg2+ content is about 19 pS. The results demonstrate that cyclic nucleotide-activated channels of olfactory receptor cells are virtually identical to photoreceptor ones.
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147
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Yamada Y, Furumichi T, Furui H, Yokoi T, Ito T, Yamauchi K, Yokota M, Hayashi H, Saito H. Roles of calcium, cyclic nucleotides, and protein kinase C in regulation of endothelial permeability. ARTERIOSCLEROSIS (DALLAS, TEX.) 1990; 10:410-20. [PMID: 2188640 DOI: 10.1161/01.atv.10.3.410] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We studied the effects of calcium, cyclic nucleotides, and protein kinase C on albumin transfer, electrical resistance, and cytoskeletal actin filaments in cultured human umbilical vein endothelial cells. The endothelial monolayer grown on collagen-treated filters markedly restricted the transfer of albumin relative to its transfer across the filter alone. Both Ca++ ionophore A23187 and ethyleneglycol tetraacetic acid disrupted the integrity of the endothelial monolayer, thereby increasing endothelial albumin transfer and decreasing electrical resistance in a concentration-dependent manner. Neither W-7, a calmodulin antagonist, nor TMB-8, an intracellular Ca++ antagonist, influenced endothelial permeability. In contrast, increases in intracellular cyclic adenosine 5'-monophosphate (AMP) and/or cyclic guanosine 5'-monophosphate (GMP) induced by dibutyryl cyclic AMP, forskolin, 3-isobutyl-1-methylxanthine, 8-bromo cyclic GMP, dibutyryl cyclic GMP, or sodium nitroprusside significantly elevated endothelial electrical resistance and inhibited albumin transfer; similar effects resulted from activation of protein kinase C by phorbol-12-myristate-13-acetate or 1-oleoyl-2-acetyl-glycerol. These substances ruffled the dense peripheral bands of F-actin without compromising the integrity of endothelial monolayer. These results suggest that calcium, cyclic nucleotides, and protein kinase C play important roles in the regulation of endothelial permeability and the maintenance of endothelial integrity.
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148
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Hamm H. Regulation by light of cyclic nucleotide-dependent protein kinases and their substrates in frog rod outer segments. J Gen Physiol 1990; 95:545-67. [PMID: 2157794 PMCID: PMC2216325 DOI: 10.1085/jgp.95.3.545] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cyclic nucleotides (both cAMP and cGMP) stimulate the phosphorylation of several proteins of 65-70, 50-52, 21, 13, and 12 kD in rod outer segments (ROS) of the frog retina. Subcellular fractionation showed that phosphopeptides of 67, 21, 13, and 12 kD were soluble and phosphopeptides of 69, 67, 50-52, and 12 kD were membrane associated at physiological ionic strength. Components I and II, 13 and 12 kD, respectively, are the major cyclic nucleotide-dependent phosphoproteins of ROS and have been reported to be phosphorylated in the dark and dephosphorylated in the light. Under unstimulated conditions, phosphorylated Components I and II were found in the soluble fraction. Cyclic nucleotide stimulation of phosphorylation resulted in increased phospho-Components I and II in the soluble fraction, and phospho-Component II on the membrane. Light had no effect on the phosphorylation level of soluble Components I and II, but it caused a depletion within 1 s of the membrane-bound phospho-Component II. A half-maximal decrease in membrane-bound Component II was seen at 5 x 10(5) rhodopsins bleached per outer segment. The cyclic nucleotide-dependent protein kinase(s) were found primarily in the peripheral membrane fraction of ROS proteins. 8-bromo cyclic AMP was two orders of magnitude more effective than 8-bromo cyclic GMP at stimulating Component I and II phosphorylation. An active peptide of the Walsh inhibitor of cAMP-dependent protein kinase [PKI(5-22)amide] blocked the phosphorylation with an IC50 of 10 nM. Photoaffinity labeling studies with 8-N3-cAMP and 8-N3-cGMP revealed the presence of a 52-kD band specifically labeled with 8-N3-cAMP, but no specific 8-N3-cGMP labeling. These data suggest that cyclic nucleotide-dependent protein phosphorylation in ROS occurs via the activation of a cAMP-dependent protein kinase.
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149
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Kotlyar BI, Pivovarov AS. Molecular mechanisms of neuronal plasticity during learning: the role of secondary messengers. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 1990; 20:118-35. [PMID: 2195376 DOI: 10.1007/bf01268131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We present published data along with our own results concerning the role of second messengers and their intracellular receptors in molecular mechanisms associated with the plasticity of neurons during learning. The participation of cyclic 3',5'-adenosine monophosphate, cyclic 3',5'-guanosine monophosphate, calcium, calmodulin, and also the metabolic products of inositol phospholipids, inositol-1,4,5-triphosphate, diacylglycerol and the protein kinase C activated by it, arachidonic acid, and the products of its lipoxygenase oxidation during the regulation of neuronal plasticity over the course of prolonged potentiation, sensitization, habituation, and classical associative training are discussed.
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Abstract
Prostaglandin F2 alpha (PGF2 alpha) release from the uterus causes luteolysis in ruminants, and oxytocin is thought to be a regulator of this release. In the present study, we have examined the mechanisms involved in oxytocin stimulation of PGF2 alpha secretion by bovine endometrium in vitro. Endometrial tissue explants, obtained from heifers at Day 19 or 20 (n = 3) and Day 0 (estrus, n = 5) of the estrous cycle, were incubated for 2 h and 6 h, and PGF2 alpha concentration in the medium was determined by radioimmunoassay (RIA). Basal PGF2 alpha release increased for up to 6 h and was significantly stimulated after 2 h of incubation with 100 microU and 1000 microU of oxytocin at Day 0 but not at Day 19 or 20. Secretion of PGF2 alpha was not affected by cholera toxin (10 ng/ml) or the cyclic nucleotide analogs dibutyryl cyclic adenosine 3',5'-monophosphate and dibutyryl cyclic guanosine 3',5'-monophosphate at a concentration of 1 mM. A protein kinase A inhibitor (500 microM) had no effect on the oxytocin-induced release of PGF2 alpha. Both the phorbol ester, 12-myristate-13-acetate (100 mM), and the non-phorbol stimulator of protein kinase C, 1-octanoyl-2-acetylglycerol (500 microM), significantly stimulated PGF2 alpha secretion to the same extent as oxytocin. Neither basal nor stimulated PGF2 alpha release was affected by the calcium ionophore A23187 (0.1-5.0 microM). However, PGF2 alpha secretion was sensitive to cycloheximide (1 microgram/ml) suggesting that protein synthesis may be involved. In conclusion, these data suggest that the stimulation of PGF2 alpha by oxytocin is via the protein kinase C effector pathway.
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