101
|
Harkin A, Connor TJ, Burns MP, Kelly JP. Nitric oxide synthase inhibitors augment the effects of serotonin re-uptake inhibitors in the forced swimming test. Eur Neuropsychopharmacol 2004; 14:274-81. [PMID: 15163436 DOI: 10.1016/j.euroneuro.2003.08.010] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2003] [Revised: 08/19/2003] [Accepted: 08/26/2003] [Indexed: 11/25/2022]
Abstract
The problem of antidepressant-resistant depression has necessitated finding ways of augmenting the actions of currently existing antidepressants. The present studies investigate the possibility of synergistic interactions between nitric oxide (NO) synthase inhibitors and antidepressants in the mouse forced swim test (FST), a pre-clinical test of antidepressant activity. Treatment with a behaviourally subactive dose of the NO synthase inhibitor NG-nitro-L-arginine (L-NA) (3 mg/kg) augmented the behavioural effect of the tricyclic antidepressant imipramine. In a similar fashion L-NA (3 mg/kg) augmented the effect of the selective serotonin re-uptake inhibitor (SSRI) fluoxetine but not the noradrenaline re-uptake inhibitor, reboxetine in the FST. The interaction observed between L-NA and fluoxetine generalised to other selective serotonin re-uptake inhibitors, namely, sertraline and citalopram in the FST. Treatment with a subactive dose of the neuronally selective NO synthase inhibitor, 7-nitroindazole (30 and 50 mg/kg), augmented the behavioural effects of imipramine and fluoxetine, respectively. Thus inhibition of NO synthase enhances the activity of antidepressants that work via a serotonergic mechanism in the FST. The results of the present investigation support a view that antidepressant effects, or enhancement of such effects in the FST, may be elicited via NO synthase inhibition. Furthermore, these data raise the possibility that inhibition of NO synthase could be used as a strategy to enhance the clinical efficacy of serotonergic antidepressants.
Collapse
Affiliation(s)
- Andrew Harkin
- Department of Pharmacology, National University of Ireland, Galway, Ireland.
| | | | | | | |
Collapse
|
102
|
Sharma S, Kheradpezhou M, Shavali S, El Refaey H, Eken J, Hagen C, Ebadi M. Neuroprotective actions of coenzyme Q10 in Parkinson's disease. Methods Enzymol 2004; 382:488-509. [PMID: 15047119 DOI: 10.1016/s0076-6879(04)82027-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Affiliation(s)
- S Sharma
- School of Medicine and Health Sciences, University of North Dakota, Grand Forks 58203, USA
| | | | | | | | | | | | | |
Collapse
|
103
|
Volz TJ, Schenk JO. L-arginine increases dopamine transporter activity in rat striatum via a nitric oxide synthase-dependent mechanism. Synapse 2004; 54:173-82. [PMID: 15452864 DOI: 10.1002/syn.20075] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Literature reports suggest that nitric oxide (NO) participates in the regulation of dopaminergic neurotransmission, possibly through interaction with cysteine residues of the dopamine transporter (DAT). Rotating disk electrode voltammetry was used to measure dopamine (DA) transport in rat striatum to determine if 1) the nitric oxide synthase (NOS) substrate, L-arginine (L-Arg), could affect DAT activity; 2) L-Arg-dependent effects on DAT activity could be blocked by NOS and guanylate cyclase inhibitors, a NO scavenger, DA, and cocaine; 3) a NO donor could affect DAT activity; and 4) L-Arg could protect the DAT from a sulfhydryl agent. L-Arg increased DAT activity by increasing V(max). NOS inhibitors (S-ethylisothiourea and S-isopropylisothiourea), a NO scavenger (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), DA, and cocaine blocked the L-Arg effect. The guanylate cyclase inhibitor, 1H-(1,2,4)-oxadiazolo[4,3a]quinoxalin-1-one, did not. The NO donor, S-nitroso-N-acetylpenicillamine, decreased DAT activity and L-Arg protected the DAT from the effects of the sulfhydryl agent N-ethylmaleimide. These results suggest that L-Arg, via NO, may play a role in regulating DAT activity in rat striatum by increasing the V(max) of DA transport. Furthermore, it is suggested that the effects of L-Arg on DAT activity may be due to modification of the DAT itself, possibly via the NO-mediated modification of DAT cysteine residues. Finally, NO produced from L-Arg may affect the DAT differently than NO from NO donors. These results further the notion that dopaminergic neurotransmission may be regulated by changes in DAT activity caused by L-Arg and NOS.
Collapse
Affiliation(s)
- Trent J Volz
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
| | | |
Collapse
|
104
|
Wazlawik E, Morato GS. Influence of drugs acting on nitric oxide-dependent pathways on ethanol tolerance in rats. Psychopharmacology (Berl) 2003; 170:343-50. [PMID: 12955299 DOI: 10.1007/s00213-003-1555-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2002] [Accepted: 05/28/2003] [Indexed: 10/26/2022]
Abstract
RATIONALE Our previous studies have shown that the inhibition of nitric oxide (NO) synthesis with drugs administered either by systemic or ICV routes blocks the development of tolerance to some of the effects of ethanol. OBJECTIVES The aim of this study was to further investigate the role of NO-dependent pathways in tolerance to the incoordinating effect of ethanol through ICV administration of drugs that activate or interfere with NO-dependent pathways. METHODS Male Wistar rats were pretreated with IP ethanol (2.7 g/ kg) or saline before receiving ICV injections of the soluble guanylyl cyclase (sGC) inhibitors methylene blue (30 nmol), 6(phenylamino)-5,8-quinolinedione (LY83583, 10 nmol), 1H-(1,2,4)-oxodiazolo (4,3-a)quinoxalin-1-one (ODQ, 1 nmol), and 4H-8-bromo-1,2,4-oxadiazolo (3,4-d)benz(b)(1,4)oxazin-1-one (NS2028, 10 nmol), or the respective control solutions. The animals were tested on the tilt plane apparatus. Tolerance was assessed 24 h after the first ethanol injection, by administering ethanol to all animals and re-testing them on the tilt plane. The effects of the cyclic guanylate 3',5'-monophosphate (cGMP) analogue, 8-bromo-cGMP (40 nmol or 80 nmol) and of the NO donors S-nitroso-N-acetylpenicillamine (SNAP, 40 or 80 nmol) and sodium nitroprusside (SNP, 40 or 80 nmol) were also studied. RESULTS All sGC inhibitors significantly blocked rapid tolerance, whereas SNP (40 nmol) and 8-bromo-cGMP (80 nmol) increased the magnitude of ethanol tolerance (ANOVA+Tukey's test). CONCLUSIONS The present results suggest that activation or inhibition of NO-dependent pathways increases or blocks rapid tolerance, respectively. These results give additional support to the hypothesis that brain NO plays a role in the development of tolerance to ethanol, but it remains to be confirmed if the same basic cellular mechanisms are also applicable to tolerance to other behavioural and/or physiological effects of this drug.
Collapse
Affiliation(s)
- Elisabeth Wazlawik
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Rua Ferreira Lima 82, 88015-420 Florianopolis, Santa Catarina, Brazil
| | | |
Collapse
|
105
|
Ishikawa M, Quock RM. Role of nitric-oxide synthase isoforms in nitrous oxide antinociception in mice. J Pharmacol Exp Ther 2003; 306:484-9. [PMID: 12721331 DOI: 10.1124/jpet.103.049551] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exposure of mice to the anesthetic gas N2O evokes a prominent antinociceptive effect that is sensitive to antagonism by nonselective nitric-oxide synthase (NOS) inhibitors. The present study was conducted to identify whether a specific NOS isoform is implicated in N2O antinociception in mice. In the abdominal constriction test, exposure of mice to 25, 50, and 70% N2O resulted in a concentration-dependent antinociceptive effect that persisted for up to 6 min following removal of the mice from the N2O atmosphere into room air. This N2O antinociceptive effect was antagonized by pretreatment with S-methyl-l-thiocitrulline (SMTC) and higher doses of l-N5-(1-iminoethyl)-ornithine (l-NIO), which reportedly inhibit the neuronal and endothelial isoforms of NOS, respectively. Nevertheless, the N2O-induced antinociception was unaffected by pretreatment with low doses of either SMTC or l-NIO or by pretreatment with 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), which selectively inhibits inducible NOS. The s.c. pretreatment with SMTC and l-NIO reduced brain NOS activity in a dose-dependent manner, whereas AMT had no such effect. Moreover, in blood pressure experiments, SMTC increased SBP in dose-unrelated fashion, whereas l-NIO showed an appreciably weaker but dose-related increase in SBP. The i.c.v. pretreatment with SMTC also reduced N2O antinociception and brain NOS activity without increasing of SBP. These results suggest that it is the neuronal isoform of NOS that is involved in mediation of the antinociceptive effect of N2O in the mice.
Collapse
Affiliation(s)
- Masago Ishikawa
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Pullman, WA 99164-6534, USA
| | | |
Collapse
|
106
|
Sharma SK, Ebadi M. Metallothionein attenuates 3-morpholinosydnonimine (SIN-1)-induced oxidative stress in dopaminergic neurons. Antioxid Redox Signal 2003; 5:251-64. [PMID: 12880480 DOI: 10.1089/152308603322110832] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Parkinson's disease is characterized by a progressive loss of dopaminergic neurons in the substantia nigra zona compacta, and in other subcortical nuclei associated with a widespread occurrence of Lewy bodies. The causes of cell death in Parkinson's disease are still poorly understood, but a defect in mitochondrial oxidative phosphorylation and enhanced oxidative stress have been proposed. We have examined 3-morpholinosydnonimine (SIN-1)-induced apoptosis in control and metallothionein-overexpressing dopaminergic neurons, with a primary objective to determine the neuroprotective potential of metallothionein against peroxynitrite-induced neurodegeneration in Parkinson's disease. SIN-1 induced lipid peroxidation and triggered plasma membrane blebbing. In addition, it caused DNA fragmentation, alpha-synuclein induction, and intramitochondrial accumulation of metal ions (copper, iron, zinc, and calcium), and enhanced the synthesis of 8-hydroxy-2-deoxyguanosine. Furthermore, it down-regulated the expression of Bcl-2 and poly(ADP-ribose) polymerase, but up-regulated the expression of caspase-3 and Bax in dopaminergic (SK-N-SH) neurons. SIN-1 induced apoptosis in aging mitochondrial genome knockout cells, alpha-synuclein-transfected cells, metallothionein double-knockout cells, and caspase-3-overexpressed dopaminergic neurons. SIN-1-induced changes were attenuated with selegiline or in metallothionein-transgenic striatal fetal stem cells. SIN-1-induced oxidation of dopamine to dihydroxyphenylacetaldehyde was attenuated in metallothionein-transgenic fetal stem cells and in cells transfected with a mitochondrial genome, and enhanced in aging mitochondrial genome knockout cells, in metallothionein double-knockout cells and caspase-3 gene-overexpressing dopaminergic neurons. Selegiline, melatonin, ubiquinone, and metallothionein suppressed SIN-1-induced down-regulation of a mitochondrial genome and up-regulation of caspase-3 as determined by reverse transcription-polymerase chain reaction. The synthesis of mitochondrial 8-hydroxy-2-deoxyguanosine and apoptosis-inducing factors were increased following exposure to 1-methyl-4-phenylpyridinium ion or rotenone. Pretreatment with selegiline or metallothionein suppressed 1-methyl-4-phenylpyridinium ion-, 6-hydroxydopamine-, and rotenone-induced increases in mitochondrial 8-hydroxy-2-deoxyguanosine accumulation. Transfection of aging mitochondrial genome knockout neurons with mitochondrial genome encoding complex-1 or melanin attenuated the SIN-1-induced increase in lipid peroxidation. SIN-1 induced the expression of alpha-synuclein, caspase-3, and 8-hydroxy-2-deoxyguanosine, and augmented protein nitration. These effects were attenuated by metallothionein gene overexpression. These studies provide evidence that nitric oxide synthase activation and peroxynitrite ion overproduction may be involved in the etiopathogenesis of Parkinson's disease, and that metallothionein gene induction may provide neuroprotection.
Collapse
Affiliation(s)
- Sushil K Sharma
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | | |
Collapse
|
107
|
Harkin A, Connor TJ, Walsh M, St John N, Kelly JP. Serotonergic mediation of the antidepressant-like effects of nitric oxide synthase inhibitors. Neuropharmacology 2003; 44:616-23. [PMID: 12668047 DOI: 10.1016/s0028-3908(03)00030-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent studies indicate that nitric oxide (NO) synthase inhibitors have antidepressant-like potential in various animal models. In the present study the behavioural activity of the NO synthase inhibitors, N(G)-nitro-L-arginine (L-NA) and 7-nitroindazole (7-NI), were assessed in a modified rat forced swimming test (FST). Both L-NA and 7-NI, dose dependently reduced immobility and increased swimming behaviour in the rat FST. This behavioural profile parallels the one previously shown with selective serotonin re-uptake inhibitors and serotonergic agonists. Thus, we examined the role of serotonin mediating the behavioural effects of L-NA and 7-NI in the rat FST. Depletion of endogenous serotonin using para-chlorophenylalanine (pCPA; 3 x 150 mg/kg, i.p.) completely blocked L-NA (20 mg/kg, i.p.) and 7-NI (20 mg/kg, i.p.)-induced reductions in immobility and increases in swimming behaviour during the FST. In conclusion these observations suggest that NO synthase inhibitors elicit their antidepressant-like activity in the modified swimming test through a serotonin dependent mechanism.
Collapse
Affiliation(s)
- A Harkin
- Department of Pharmacology, National University of Ireland, Galway, Ireland.
| | | | | | | | | |
Collapse
|
108
|
Dere E, De Souza Silva MA, Topic B, Fiorillo C, Li JS, Sadile AG, Frisch C, Huston JP. Aged endothelial nitric oxide synthase knockout mice exhibit higher mortality concomitant with impaired open-field habituation and alterations in forebrain neurotransmitter levels. GENES, BRAIN, AND BEHAVIOR 2002; 1:204-13. [PMID: 12882365 DOI: 10.1034/j.1601-183x.2002.10402.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Endothelial nitric oxide synthase (eNOS) has been implicated in various brain and peripheral pathologies such as renal failure, heart failure or stroke. Consequently, the mortality rate of aged eNOS knockout mice (eNOS-/-) was higher than that of age-matched (18-22 months old) controls. Only seven of the original 14 eNOS-/- animals that participated in the study reached the age of 18 months or older, whereas no control mice died during this life span. In order to assess the behavioral and neurochemical consequences of chronic eNOS deficiency we examined whether the surviving aged eNOS-/- mice showed changes in terms of motor, emotional, exploratory and neurochemical parameters. Aged eNOS-/- mice showed reduced exploratory activity in the open-field with no habituation observable neither within sessions nor after repeated exposures. Pole test performance of eNOS-/- mice was comparable to controls. In the elevated plus-maze eNOS-/- mice did not differ from controls in terms of time spent in and entries into arms, but showed less locomotion on the open arms. The most prominent neurochemical alterations in the forebrains of aged eNOS-/- mice were: (a) increased acetylcholine levels in the neostriatum; (b) decreased noradrenaline concentrations in the ventral striatum; and (c) lower serotonin levels in the frontal cortex and ventral striatum. The present findings suggest that mice which survived chronic eNOS-deficiency into old age, show some behavioral and neurochemical phenotypes distinct from adult eNOS-/- mice.
Collapse
Affiliation(s)
- E Dere
- Institute of Physiological Psychology, Center for Biological and Medical Research, University of Düsseldorf D-40225 Düsseldorf, Germany
| | | | | | | | | | | | | | | |
Collapse
|
109
|
Kang JH, Jeong W, Park Y, Lee SY, Chung MW, Lim HK, Park IS, Choi KH, Chung SY, Kim DS, Park CS, Hwang O, Kim JI. Aroclor 1254-induced cytotoxicity in catecholaminergic CATH.a cells related to the inhibition of NO production. Toxicology 2002; 177:157-66. [PMID: 12135619 DOI: 10.1016/s0300-483x(02)00142-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The neuronal nitric oxide synthase (nNOS) specific inhibitor, 7-nitroindazole (7-NI), and the nitric oxide (NO) donor (S-nitroso-N-acetylpenicillarnine, SNAP) were used to study the role of NO in polychlorinated biphenyl (PCB: Aroclor 1254)-induced cytotoxicity in the immortalized dopaminergic cell line (CATH.a cells), derived from the central nervous system of mice. Treatment of the dopaminergic cells with various concentrations of Aroclor 1254 (0.5-10 microg/ml), a commercial PCB mixture, showed significant cytotoxicity as evaluated by lactate dehydrogenase (LDH) release and assessment of cell viability, depending on the concentration used. We also observed that Aroclor 1254 treatment reduced the level of nNOS expression. Furthermore, the cytotoxicity of Aroclor 1254 was augmented by 10 microM of 7-NI, which alone did not produce cytotoxicity, while it was protected by treatment with SNAP. Depending on the concentrations of Aroclor 1254 used, intracellular dopamine and dihydroxyphenylacetic acid (DOPAC) concentrations were significantly decreased. Therefore, these results suggest that PCBs have the potential for dopaminergic neurotoxicity, which may be related with the PCBs-mediated alteration of NO production originating from nNOS at least in part.
Collapse
Affiliation(s)
- Ju Hee Kang
- Department of Pharmacology, National Institute of Toxicological Research, Korea Food and Drug Administration, 5 Nokbundong, Eunpyung-Gu, Seoul, South Korea
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
110
|
Arakawa Y, Takao E, Hirotani Y, Kato I, Li J, Yanaihara N, Yanaihara C, Iwanaga T, Kurokawa N. Immunochemical characterization and measurement of neuronal type nitric oxide synthase in human neuroblastoma NB-OK-1 cell using novel anti-synthetic peptide antibody and specific immunoassay system. REGULATORY PEPTIDES 2002; 106:115-23. [PMID: 12047918 DOI: 10.1016/s0167-0115(02)00059-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We developed a sensitive and specific immunoassay system for human neuronal nitric oxide synthase (hnNOS) using synthetic hnNOS(998-1024) peptide and anti-hnNOS(998-1024) antibody. The novel antibody and radioimmunoassay system revealed a typical nNOS protein in human neuroblastoma NB-OK-1 cell (160 kDa, 180 fmol/10(6) cells). The kinetic parameters of the enzyme were K(m)=4.88 microM and V(max)=4.34 pmol/min/mg protein for L-arginine. On incubation of NB-OK-1 cell for 24 h, betamethasone phosphate decreased both nNOS-immunoreactivity (nNOS-IR) and enzymatic activity in the cell dose-dependently. On the other hand, pituitary adenylate cyclase activating polypeptide(1-38) (PACAP38) increased both nNOS-IR and enzymatic activity at concentrations of 10(-10) and 10(-9) M, but inversely decreased both at 10(-7) M. These suggest the positive and negative implications of endogenous NO in proliferation and differentiation of the cell, which support mitogenic activity of NO generated by nNOS in the cell. The present findings also provided evidence that the quantitative change of nNOS protein controls the integrated activity of the enzyme in the cell and, in turn, substantiate the validity and reliability of the present immunoassay system for hnNOS and its practical usefulness.
Collapse
Affiliation(s)
- Yukio Arakawa
- Laboratory of Pharmaceutical Sciences, Osaka University Graduate School of Medicine, Suita, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
111
|
West AR, Galloway MP, Grace AA. Regulation of striatal dopamine neurotransmission by nitric oxide: effector pathways and signaling mechanisms. Synapse 2002; 44:227-45. [PMID: 11984858 DOI: 10.1002/syn.10076] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An important role for the reactive gas nitric oxide (NO) in regulating striatal dopaminergic neurotransmission was identified shortly after initial observations indicated that this unorthodox neurotransmitter mediates many of the influences of glutamatergic neurotransmission in the cerebellum, cortex, and hippocampus. While the precise actions of NO on striatal presynaptic and postsynaptic elements remain to be fully characterized, the recent application of sophisticated anatomical, neurochemical, and electrophysiological approaches to the study of nitrergic signaling has revealed that NO exerts a powerful influence both on tonic extracellular dopamine (DA) levels and phasic DA neuron spike activity via the modulation of intrinsic striatal mechanisms and striatonigral feedback loops. Although the nature of the NO-mediated modulatory influence on DA neurotransmission was initially clouded by seemingly conflicting neurochemical observations, a growing body of literature and understanding of the diverse signaling mechanisms and effector pathways utilized by NO indicates that NO exerts a primary facilitatory influence over tonic and phasic dopaminergic neurotransmission under physiological conditions. A review of neurochemical and electrophysiological studies examining the influence of endogenous and exogenous NO on DA neurotransmission indicates that NO signaling exerts multiple effects on local striatal circuits and projection neurons involved in regulating basal ganglia output and nigrostriatal DA neuron activity. In addition to summarizing these influences, the current review focuses on the mechanisms utilized by striatal NO signaling pathways involved in modulating DA transmission at the level of the terminal and cell body and attempts to integrate these observations into a functional model of NO-dependent regulation of basal ganglia systems.
Collapse
Affiliation(s)
- Anthony R West
- Department of Neuroscience, 446 Crawford Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | | | | |
Collapse
|
112
|
Wazlawik E, Morato GS. Effects of intracerebroventricular administration of 7-nitroindazole on tolerance to ethanol. Brain Res Bull 2002; 57:165-70. [PMID: 11849822 DOI: 10.1016/s0361-9230(01)00736-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Previous studies have shown that nitric oxide (NO) is involved in the development of rapid tolerance to the motor incoordination produced by ethanol. In order to further investigate this involvement, three experiments were undertaken using the tilt-plane and the hypothermia tests. The first demonstrated that 7-nitroindazole (7-NI), a preferential neuronal NO synthase (nNOS) inhibitor, injected by intracerebroventricular (i.c.v.) route, blocked the development of rapid tolerance to ethanol-induced motor incoordination. This effect was prevented by i.c.v. injection of L-arginine. The second experiment showed that D-arginine did not influence the blockade of tolerance produced by 7-NI. The third experiment revealed that i.c.v. injection of 7-NI also blocked the development of tolerance to the hypothermic effect of ethanol. These results support the hypothesis that nNOS-derived NO participates in the development of rapid tolerance to ethanol.
Collapse
Affiliation(s)
- Elisabeth Wazlawik
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Rua Ferreira Lima 82, 88015-420 Florianópolis, SC, Brazil
| | | |
Collapse
|
113
|
Starkey SJ, Grant AL, Hagan RM. A rapid and transient synthesis of nitric oxide (NO) by a constitutively expressed type II NO synthase in the guinea-pig suprachiasmatic nucleus. Br J Pharmacol 2001; 134:1084-92. [PMID: 11682457 PMCID: PMC1573026 DOI: 10.1038/sj.bjp.0704330] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. We have measured extracellular NO/NO(2)(-) concentrations in guinea-pig suprachiasmatic nucleus (SCN) brain slices using fast cyclic voltammetry. A rapid and transient signal equivalent to 2.2+/-0.2 microM NO/NO(2)(-) (mean+/-s.e.mean, n=13) was detected at 1.26 V, the peak oxidation potential for NO, following local electrical stimulation (five pulses of 0.1 ms duration at 100 Hz, delivered every 5 min). 2. The NO/NO(2)(-) signal was inhibited by the non-selective nitric oxide synthase (NOS) inhibitors L-NAME, L-NMMA and the highly selective type II NOS (iNOS) inhibitor 1400 W (Garvey et al., 1997) in a concentration-dependent manner. IC(50) values were 229 microM (65 - 801, n=3, geomean and 95% confidence intervals (C.I.)), 452 nM (88 - 2310, n=5), and 14.2 microM (3.6 - 54.4, n=5), with maximum inhibitions of 82.8+/-6.7, 46.0+/-8.1, and 90.6+/-3.6%, respectively. 3. Exposure of the slices to the protein synthesis inhibitor cyclohexamide or the inhibitor of type II NOS induction dexamethasone immediately following slice cutting, and for a subsequent 4 - 5 h, did not inhibit the NO/NO(2)(-) signal. 4. The evoked NO/NO(2)(-) signal was not reduced following 6 h perfusion in Ca(2+)-free media, consistent with a Ca(2+)-independent type II NOS activity. 5. PCR for type II NOS revealed the presence of this isotype in the SCN, even immediately following removal of the brain. 6. These studies provide the first evidence to suggest a functional, constitutively-active type II NOS within the brain of normal, healthy adult animals, and add type II NOS to the multiple isotypes of NO synthase playing a role within the mammalian SCN.
Collapse
Affiliation(s)
- S J Starkey
- Neuropharmacology II, Centre of Excellence for drug discovery in Psychiatry, GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY.
| | | | | |
Collapse
|
114
|
Oh GS, Pae HO, Seo WG, Shin MK, Kim IK, Chai KY, Yun YG, Kwon TO, Lim JS, Chung HT. Inhibitory effect of retinoic acid on expression of inducible nitric oxide synthase gene in l929 cells. Immunopharmacol Immunotoxicol 2001; 23:335-42. [PMID: 11694025 DOI: 10.1081/iph-100107334] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Inflammation has been known to be associated with excess synthesis of nitric oxide (NO) by inducible NO synthase (iNOS). Retinoids have been reported to have anti-inflammatory activity, but the mechanism by which they can elicit this activity is poorly understood. The effects of retinoids on NO synthesis and iNOS gene expression in murine fibroblast L929 cells were examined. Treatment of the cells with interferon-y resulted in excess NO synthesis and iNOS gene expression. All-trans-retinoic acid significantly inhibited NO synthesis and iNOS gene expression in a dose-dependent manner. Similarly, 9-cis-retinoic acid also inhibited NO synthesis, but retinol did not show any inhibitory effect on NO synthesis. These findings suggest that the modulation of iNOS gene expression is another possible pathway by which retinoids may function as anti-inflammatory agents.
Collapse
Affiliation(s)
- G S Oh
- Medicinal Resources Research Center Wonkwang University School of Medicine, Iksan, Chonbuk, South Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|