scholarly journals The role of adrenergic agonists on glycogenolysis in rat hepatocyte cultures and possible involvement of NO

2007 ◽  
pp. 419-426
Author(s):  
J Hodis ◽  
N Kutinová-Canová ◽  
P Potměšil ◽  
L Kameníková ◽  
E Kmoníčková ◽  
...  
Keyword(s):  
Metabolic Diseases ◽  
Present Report ◽  
Rat Hepatocytes ◽  
No Synthase ◽  
Inos Mrna ◽  
No Production ◽  
Adrenergic Agonists ◽  
No Donor ◽  
Glucose Levels ◽  
Nos Inhibitors

Certain liver metabolic diseases point to the presence of disturbances in glycogen deposition. Epinephrine raises the cAMP level that activates protein kinase A leading to the activation of phosphorylase and glycogen breakdown. In the present report, we sought to investigate whether NO is produced during adrenoceptor agonist-induced glycogenolysis in rat hepatocytes in cultures. Isolated glycogen rich rat hepatocytes in cultures were used. NO production (NO(2)(-)) was assessed under the effect of adrenergic agonists and adrenergic agonist/antagonist pairs, dibutyryl cyclic AMP sodium-potassium salt (db-cAMP), NO synthase (NOS) inhibitors N(omega)-nitro-L-arginine methyl ester (L-NAME), aminoguanidine (AG) and the NO donor S-nitroso-N-acetyl penicillamine (SNAP). The inducible NO synthase (iNOS) mRNA was examined by the reverse transcription-polymerase chain reaction (RT-PCR). Glycogenolysis was quantified by glucose levels released into medium. The amount of glucose and NO(2)(-) released by hepatocytes was increased as a result of epinephrine, phenylephrine or db-cAMP treatments. The increase in glucose and NO(2)(-) released by epinephrine or phenylephrine was blocked or reduced by prazosin pretreatment and by NOS inhibitors aminoguanidine and L-NAME. iNOS gene expression was up-regulated by epinephrine. It can be concluded that glycogenolysis occurs through -adrenoceptor stimulation and a signaling cascade may involve NO production.

scholarly journals Glucose release as a response to glucagon in rat hepatocyte culture: involvement of NO signaling

2008 ◽  
pp. 569-575
Author(s):  
H Farghali ◽  
J Hodis ◽  
N Kutinová-Canová ◽  
P Potměšil ◽  
E Kmoníčková ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Glycogen Synthase ◽  
Inos Mrna ◽  
No Production ◽  
Rat Hepatocyte ◽  
No Donor ◽  
Glucagon Receptor ◽  
Nos Inhibitors ◽  
No Signaling ◽  
Rat Hepatocyte Culture

Glucagon and α-adrenergic-induced glycogenolysis is realized via the agonist/adenylyl cyclase/cAMP/protein kinase signaling pathway or via the activation of phosphorylase kinase by the mobilized calcium that supports the inhibition of glycogen synthase, respectively. The role of nitric oxide (NO) in this process has not been extensively studied. The present work was directed to the question whether NO is produced during glucagon-induced glycogenolysis in rat hepatocyte in a similar way like α-adrenoceptor stimulation. Glycogen-rich hepatocyte cultures were used. NO production (NO2-) was assessed under the influence of glucagon, dibutyryl cyclic AMP (db-cAMP), forskolin, the nitric oxide synthase (NOS) inhibitors Nω-nitro-Larginine methyl ester (L-NAME) and aminoguanidine, and the NO donor S-nitroso-N-acetyl penicillamine (SNAP). Inducible NOS (iNOS) mRNA was examined by reverse transcription-polymerase chain reaction. Glycogenolysis was followed up by estimation of medium glucose levels. The amount of glucose and NO2 - released by glycogen-rich hepatocytes was increased as a result of glucagon, db-cAMP, forskolin and SNAP treatments. iNOS gene expression was upregulated by glucagon. Glycogenolysis that occurs through glucagon receptor stimulation involves NO production downstream of transduction pathways through an isoform of NO synthase. The present and previous studies document possible involvement of NO signaling in glycogenolytic response to glucagon and adrenergic agonists in hepatocytes.

Caspase Activation Is Required for Nitric Oxide–Mediated, CD95(APO-1/Fas)–Dependent and Independent Apoptosis in Human Neoplastic Lymphoid Cells

Blood ◽  
1998 ◽  
Vol 91 (11) ◽  
pp. 4311-4320 ◽  
Author(s):  
Katerina Chlichlia ◽  
Marcus E. Peter ◽  
Marian Rocha ◽  
Carsten Scaffidi ◽  
Mariana Bucur ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Present Report ◽  
Lymphoid Cells ◽  
Jurkat Cells ◽  
Target Cells ◽  
No Production ◽  
No Donor ◽  
Synthase Inhibitor ◽  
Inhibitor Of Protein Synthesis

Abstract Nitric oxide (NO), an important effector molecule involved in immune regulation and host defense, was shown to induce apoptosis in lymphoma cells. In the present report the NO donor glycerol trinitrate was found to induce apoptosis in Jurkat cells that are sensitive to CD95-mediated kill. In contrast, a CD95-resistant Jurkat subclone showed substantial protection from apoptosis after exposure to NO. NO induced mRNA expression of CD95 (APO-1/Fas) and TRAIL/APO-2 ligands. Moreover, NO triggered apoptosis in freshly isolated human leukemic lymphocytes which were also sensitive to anti-CD95 treatment. The ability of NO to induce apoptosis was completely blocked by a broad-spectrum ICE (interleukin-1β converting enzyme)-protease/caspase inhibitor and correlated with FLICE/caspase-8 activation. This activation was abrogated in some neoplastic lymphoid cells but not in others by the inhibitor of protein synthesis cycloheximide. Our results were confirmed using an in vitro experimental model of coculture of human lymphoid target cells with activated bovine endothelial cells generating NO as effectors. Furthermore, the inhibition of endogenous NO production with the inducible NO synthase inhibitor NG-monomethyl-L-arginine caused a complete abrogation of the apoptotic effect. Our data provide evidence that NO-induced apoptosis in human neoplastic lymphoid cells strictly requires activation of caspases, in particular FLICE, the most CD95 receptor-proximal caspase. Depending on the cell line tested this activation required or was independent of the CD95 receptor/ligand system.

scholarly journals The PSD95–nNOS interface

2005 ◽  
Vol 168 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Jiong Cao ◽  
Jenni I. Viholainen ◽  
Caroline Dart ◽  
Helen K. Warwick ◽  
Mark L. Leyland ◽  
...  
Keyword(s):  
Cell Death ◽  
No Production ◽  
No Donor ◽  
Calcium Dependent ◽  
Upstream Regulator ◽  
Neuroprotective Drugs ◽  
Downstream Effectors ◽  
Nos Inhibitors ◽  
Excitotoxic Cell Death ◽  
The Relationship

The stress-activated protein kinase p38 and nitric oxide (NO) are proposed downstream effectors of excitotoxic cell death. Although the postsynaptic density protein PSD95 can recruit the calcium-dependent neuronal NO synthase (nNOS) to the mouth of the calcium-permeable NMDA receptor, and depletion of PSD95 inhibits excitotoxicity, the possibility that selective uncoupling of nNOS from PSD95 might be neuroprotective is unexplored. The relationship between excitotoxic stress–generated NO and activation of p38, and the significance of the PSD95–nNOS interaction to p38 activation also remain unclear. We find that NOS inhibitors reduce both glutamate-induced p38 activation and the resulting neuronal death, whereas NO donor has effects consistent with NO as an upstream regulator of p38 in glutamate-induced cell death. Experiments using a panel of decoy constructs targeting the PSD95–nNOS interaction suggest that this interaction and subsequent NO production are critical for glutamate-induced p38 activation and the ensuing cell death, and demonstrate that the PSD95–nNOS interface provides a genuine possibility for design of neuroprotective drugs with increased selectivity.

The nitric oxide donor molsidomine rescues cardiac function in rats with chronic kidney disease and cardiac dysfunction

2010 ◽  
Vol 299 (6) ◽  
pp. H2037-H2045 ◽  
Author(s):  
Lennart G. Bongartz ◽  
Branko Braam ◽  
Marianne C. Verhaar ◽  
Maarten Jan M. Cramer ◽  
Roel Goldschmeding ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Low Dose ◽  
Left Ventricular Systolic Dysfunction ◽  
Systolic Dysfunction ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
No Synthase ◽  
Nitric Oxide Donor ◽  
No Production ◽  
No Donor

We recently developed a rat model of cardiorenal failure that is characterized by severe left ventricular systolic dysfunction (LVSD) and low nitric oxide (NO) production that persisted after temporary low-dose NO synthase inhibition. We hypothesized that LVSD was due to continued low NO availability and might be reversed by supplementing NO. Rats underwent a subtotal nephrectomy and were treated with low-dose NO synthase inhibition with Nω-nitro-l-arginine up to week 8. After 3 wk of washout, rats were treated orally with either the long-acting, tolerance-free NO donor molsidomine (Mols) or vehicle (Veh). Cardiac and renal function were measured on weeks 11, 13, and 15. On week 16, LV hemodynamics and pressure-volume relationships were measured invasively, and rats were killed to quantify histological damage. On week 15, blood pressure was mildly reduced and creatinine clearance was increased by Mols (both P < 0.05). Mols treatment improved ejection fraction (53 ± 3% vs. 37 ± 2% in Veh-treated rats, P < 0.001) and stroke volume (324 ± 33 vs. 255 ± 15 μl in Veh-treated rats, P < 0.05). Rats with Mols treatment had lower end-diastolic pressures (8.5 ± 1.1 mmHg) than Veh-treated rats (16.3 ± 3.5 mmHg, P < 0.05) and reduced time constants of relaxation (21.9 ± 1.8 vs. 30.9 ± 3.3 ms, respectively, P < 0.05). The LV end-systolic pressure-volume relationship was shifted to the left in Mols compared with Veh treatment. In summary, in a model of cardiorenal failure with low NO availability, supplementing NO significantly improves cardiac systolic and diastolic function without a major effect on afterload.

scholarly journals An increase in nitric oxide produced by rat peritoneal neutrophils is not involved in cell apoptosis

1995 ◽  
Vol 4 (3) ◽  
pp. 222-228 ◽  
Author(s):  
I. M. Fierro ◽  
C. Barja-Fidalgo ◽  
R. M. Canedo ◽  
F. Q. Cunha ◽  
S. H. Ferreira
Keyword(s):  
Nitric Oxide ◽  
Cell Apoptosis ◽  
No Synthase ◽  
The Other ◽  
Polymorphonuclear Neutrophils ◽  
No Production ◽  
Spontaneous Release ◽  
No Donor ◽  
Carrageenin Injection

Polymorphonuclear neutrophils (PMN) obtained from carrageenin-stimulated peritoneal cavities of rats, but not blood PMN, spontaneously produced nitric oxide (NO) when incubatedin vitro. Incubation of the cells with the NO synthase inhibitors, L-imino-ethyl-L-ornithine (L-NIO) or NG-monomethyl-L-arginine (L-NMMA), inhibited NO production. This inhibition could be reversed by L-arginine. Incubation of PMN with lipopolysaccharide (LPS) failed to enhance NO production. Pretreatment of the rats with dexamethasone (DEXA) prior to carrageenin injection or incubation of PMN with the glucocorticoidin vitropartially inhibited the spontaneous release of NO. On the other hand, when PMN obtained from DEXA pretreated rats were incubatedin vitrowith DEXA, NO synthase activity and hence NO generation were almost abolished. A similar inhibition was also observed following the addition of L-NIO or cycloheximide to cultures of carrageenin-elicited PMN. The NO production by PMN did not appear to be related to cell viability or apoptosis. Indeed, neither the blockade of NO generation by L-NIO nor the incubation of the neutrophils with a NO donor, S-nitroso-acetylpenicillamine (SNAP) modified the pattern of LDH release or DNA fragmentation. In summary, it appears that PMN migration triggers a continuous NO synthesis, and that NO produced by these cells is not related to their apoptosis.

scholarly journals Nitric Oxide in the Spinal Cord Is Involved in the Hyperalgesia Induced by Tetrahydrobiopterin in Chronic Restraint Stress Rats

2021 ◽  
Vol 15 ◽  
Author(s):  
Ying Huang ◽  
Bo Jiao ◽  
Bo Zhu ◽  
Bingrui Xiong ◽  
Pei Lu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Spinal Cord ◽  
Restraint Stress ◽  
Intrathecal Injection ◽  
Thermal Hyperalgesia ◽  
No Synthase ◽  
Stressful Event ◽  
Inos Mrna ◽  
No Production ◽  
Pain Symptoms

It has been well recognized that exposure to chronic stress could increase pain responding and exacerbate pain symptoms, resulting in stress-induced hyperalgesia. However, the mechanisms underlying stress-induced hyperalgesia are not yet fully elucidated. To this end, we observed that restraint as a stressful event exacerbated mechanical and thermal hyperalgesia, accompanied with up-regulation of nitric oxide (NO) (P &lt; 0.001), GTP cyclohydrolase 1 (GCH1) (GCH1 mRNA: P = 0.001; GCH1 protein: P = 0.001), and tetrahydrobiopterin (BH4) concentration (plasma BH4: P &lt; 0.001; spinal BH4: P &lt; 0.001) on Day 7 in restraint stress (RS) rats. Intrathecal injection of Nω-nitro-L-arginine methyl ester (L-NAME), a non-specific NO synthase inhibitor, or N-([3-(aminomethyl)phenyl]methyl) ethanimidamide, a special inhibitor of inducible NO synthase (iNOS), for seven consecutive days attenuated stress-induced hyperalgesia and decreased the production of NO (P &lt; 0.001). Interestingly, 7-nitro indazole, a special inhibitor of neuronal NO synthase, alleviated stress-induced hyperalgesia but did not affect spinal NO synthesis. Furthermore, intrathecal injection of BH4 not only aggravated stress-induced hyperalgesia but also up-regulated the expression of spinal iNOS (iNOS mRNA: P = 0.015; iNOS protein: P &lt; 0.001) and NO production (P &lt; 0.001). These findings suggest that hyperalgesia induced by RS is associated with the modulation of the GCH1–BH4 system and constitutively expressed spinal iNOS. Thus, the GCH1–BH4–iNOS signaling pathway may be a new novel therapeutic target for pain relief in the spinal cord.

Caspase Activation Is Required for Nitric Oxide–Mediated, CD95(APO-1/Fas)–Dependent and Independent Apoptosis in Human Neoplastic Lymphoid Cells

Blood ◽  
1998 ◽  
Vol 91 (11) ◽  
pp. 4311-4320 ◽  
Author(s):  
Katerina Chlichlia ◽  
Marcus E. Peter ◽  
Marian Rocha ◽  
Carsten Scaffidi ◽  
Mariana Bucur ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Present Report ◽  
Lymphoid Cells ◽  
Jurkat Cells ◽  
Target Cells ◽  
No Production ◽  
No Donor ◽  
Synthase Inhibitor ◽  
Inhibitor Of Protein Synthesis

Nitric oxide (NO), an important effector molecule involved in immune regulation and host defense, was shown to induce apoptosis in lymphoma cells. In the present report the NO donor glycerol trinitrate was found to induce apoptosis in Jurkat cells that are sensitive to CD95-mediated kill. In contrast, a CD95-resistant Jurkat subclone showed substantial protection from apoptosis after exposure to NO. NO induced mRNA expression of CD95 (APO-1/Fas) and TRAIL/APO-2 ligands. Moreover, NO triggered apoptosis in freshly isolated human leukemic lymphocytes which were also sensitive to anti-CD95 treatment. The ability of NO to induce apoptosis was completely blocked by a broad-spectrum ICE (interleukin-1β converting enzyme)-protease/caspase inhibitor and correlated with FLICE/caspase-8 activation. This activation was abrogated in some neoplastic lymphoid cells but not in others by the inhibitor of protein synthesis cycloheximide. Our results were confirmed using an in vitro experimental model of coculture of human lymphoid target cells with activated bovine endothelial cells generating NO as effectors. Furthermore, the inhibition of endogenous NO production with the inducible NO synthase inhibitor NG-monomethyl-L-arginine caused a complete abrogation of the apoptotic effect. Our data provide evidence that NO-induced apoptosis in human neoplastic lymphoid cells strictly requires activation of caspases, in particular FLICE, the most CD95 receptor-proximal caspase. Depending on the cell line tested this activation required or was independent of the CD95 receptor/ligand system.

Excessive NO production dose not account for the inhibition of hepatic gluconeogenesis in endotoxemia

1996 ◽  
Vol 271 (4) ◽  
pp. G621-G628 ◽  
Author(s):  
J. Ou ◽  
L. Molina ◽  
Y. M. Kim ◽  
T. R. Billiar
Keyword(s):  
No Synthase ◽  
No Production ◽  
Wild Type ◽  
Gapdh Activity ◽  
Nos Inhibitors ◽  
Before And After ◽  
Gluconeogenic Substrates ◽  
Fasted Rats

The pattern of inhibition of gluconeogenesis in hepatocytes was compared between endotoxemia in vivo and nitric oxide (NO) exposure in vitro. Fasted rats were injected with lipopolysaccharide (LPS; 12 mg/kg) or with vehicle alone. After 2-24 h, hepatocytes were isolated, placed in suspension, and incubated for 1 h with various gluconeogenic substrates that enter at different sites of the gluconeogenic pathway. Hepatocytes from LPS-treated rats exhibited up to a 50% decrease in gluconeogenesis for substrates that enter proximal to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) beginning at 6 h, followed by a nadir at 12 h after LPS. Although hepatocytes exposed to exogenous NO (S-nitroso-N-acetylpenicillamine) also exhibited a depressed gluconeogenesis, the pattern was not the same with inhibition in gluconeogenesis for substrates that enter the pathway both before and after GAPDH. Furthermore, when rats injected with LPS were subjected to a constant portal infusion (Alzet pump) of the NO synthase (NOS) inhibitors, NG-monomethyl-L-arginine or aminoguanidine, no changes in the LPS-induced gluconeogenesis suppression were seen. In addition, no difference in LPS-induced inhibition of gluconeogenesis was detected when hepatocytes from inducible NO synthase (NOS-2) knockout mice were compared with cells obtained from wild-type mice. Minimal decreases in GAPDH activity were measured in hepatocytes from the LPS-treated rats, whereas the activity of phosphoenol pyruvate carboxykinase (PEPCK) declined up to 40%, independent of NO synthesis. These data indicate that NO does not account for the inhibition of gluconeogenesis in endotoxemia, and they provide support for NO-independent reduction in PEPCK activity as a more plausible explanation.

scholarly journals Nitric oxide-dependent CYP2B degradation is potentiated by a cytokine-regulated pathway and utilizes the immunoproteasome subunit LMP2

2012 ◽  
Vol 445 (3) ◽  
pp. 377-382 ◽  
Author(s):  
Haiyan Sun ◽  
Choon-myung Lee ◽  
Shweta Tripathi ◽  
Kyung-Bo Kim ◽  
Edward T. Morgan
Keyword(s):  
Nitric Oxide ◽  
Cytochrome P450 ◽  
Protein Degradation ◽  
Rat Hepatocytes ◽  
No Synthase ◽  
Proteolytic Degradation ◽  
Independent Action ◽  
Cytochrome P450 Enzymes ◽  
No Donor ◽  
Synthase Inhibitor

CYP2B proteins in rat hepatocytes undergo NO-dependent proteolytic degradation, but the mechanisms and the reasons for the specificity towards only certain P450 (cytochrome P450) enzymes are yet unknown. In the present study we found that down-regulation of CYP2B proteins by the NO donor NOC-18 is accelerated by pretreatment of the hepatocytes with IL-1 (interleukin-1β) in the presence of an NO synthase inhibitor, suggesting that an NO-independent action of IL-1 contributes to the lability of CYP2B proteins. The immunoproteasome subunit LMP2 (large multifunctional peptidase 2) was significantly expressed in hepatocytes under basal conditions, and IL-1 induced LMP2 within 6–12 h of treatment. CYP2B protein degradation in response to IL-1 was attenuated by the selective LMP2 inhibitor UK-101, but not by the LMP7 inhibitor IPSI. The results show that LMP2 contributes to the NO-dependent degradation of CYP2B proteins, and suggest that induction of LMP2 may be involved in the potentiation of this degradation by IL-1.

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