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Dias JP, Gariépy HDB, Ongali B, Couture R. Brain kinin B1 receptor is upregulated by the oxidative stress and its activation leads to stereotypic nociceptive behavior in insulin-resistant rats. Peptides 2015; 69:118-26. [PMID: 25959537 DOI: 10.1016/j.peptides.2015.04.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/24/2015] [Accepted: 04/27/2015] [Indexed: 11/22/2022]
Abstract
Kinin B1 receptor (B1R) is virtually absent under physiological condition, yet it is highly expressed in models of diabetes mellitus. This study aims at determining: (1) whether B1R is induced in the brain of insulin-resistant rat through the oxidative stress; (2) the consequence of B1R activation on stereotypic nocifensive behavior; (3) the role of downstream putative mediators in B1R-induced behavioral activity. Sprague-Dawley rats were fed with 10% D-glucose in their drinking water or tap water (controls) for 4 or 12 weeks, combined either with a standard chow diet or a diet enriched with α-lipoic acid (1 g/kg feed) for 4 weeks. The distribution and density of brain B1R binding sites were assessed by autoradiography. Behavioral activity evoked by i.c.v. injection of the B1R agonist Sar-[D-Phe(8)]-des-Arg(9)-BK (10 μg) was measured before and after i.c.v. treatments with selective antagonists (10 μg) for kinin B1 (R-715, SSR240612), tachykinin NK1 (RP-67580) and glutamate NMDA (DL-AP5) receptors or with the inhibitor of NOS (L-NNA). Results showed significant increases of B1R binding sites in various brain areas of glucose-fed rats that could be prevented by the diet containing α-lipoic acid. The B1R agonist elicited head scratching, grooming, sniffing, rearing, digging, licking, face washing, wet dog shake, teeth chattering and biting in glucose-fed rats, which were absent after treatment with α-lipoic acid or antagonists/inhibitors. Data suggest that kinin B1R is upregulated by the oxidative stress in the brain of insulin-resistant rats and its activation causes stereotypic nocifensive behavior through the release of substance P, glutamate and NO.
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Affiliation(s)
- Jenny Pena Dias
- Department of Molecular and Integrative Physiology, Faculty of Medicine, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Helaine De Brito Gariépy
- Department of Molecular and Integrative Physiology, Faculty of Medicine, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Brice Ongali
- Department of Molecular and Integrative Physiology, Faculty of Medicine, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Réjean Couture
- Department of Molecular and Integrative Physiology, Faculty of Medicine, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada.
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Role of nitric oxide in the regulation of motor function. An overview of behavioral, biochemical and histological studies in animal models. Pharmacol Rep 2014; 65:1043-55. [PMID: 24399702 DOI: 10.1016/s1734-1140(13)71464-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/27/2013] [Indexed: 12/17/2022]
Abstract
A compelling body of evidence suggests that nitric oxide (NO), a unique gaseous neurotransmitter and neuromodulator plays a key role in the regulation of motor function. Recently, the interest of researchers concentrates on the NO - soluble guanylyl cyclase (sGC) - cyclic GMP (cGMP) signaling pathway in the striatum as a new target for the treatment of Parkinson's disease (PD). The aim of the study is to review the available literature referring to the role of NO in the integration of basal ganglia functions. First, attention has been focused on behavioral effects of NO donors and neuronal nitric oxide synthase (nNOS) inhibitors in the modulation of motor behavior. Then, disturbances in the nitrergic neurotransmission in PD and its 6-OHDA animal model have been presented. Moreover, the most current data demonstrating the contribution of both dopamine and glutamate to the regulation of NO biosynthesis in the striatum have been analyzed. Finally, the role of NO in the tonic and phasic dopamine release as well as in the regulation of striatal output pathways also has been discussed.
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Lorenc-Koci E, Czarnecka A, Lenda T, Kamińska K, Konieczny J. Molsidomine, a nitric oxide donor, modulates rotational behavior and monoamine metabolism in 6-OHDA lesioned rats treated chronically with L-DOPA. Neurochem Int 2013; 63:790-804. [PMID: 24090640 DOI: 10.1016/j.neuint.2013.09.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 09/18/2013] [Accepted: 09/24/2013] [Indexed: 11/19/2022]
Abstract
Some biochemical and histological studies of Parkinson's disease patients' brains and 6-OHDA-lesioned rats suggest that dopaminergic dennervation of the striatum leads to the nitrergic system hypofunction in this structure. Hence, recently the modulation of nitric oxide (NO)- soluble guanylyl cyclase-cyclic GMP signaling is considered to be a new target for the treatment of Parkinson's disease. The aim of our study was to examine the impact of chronic combined treatment with low doses of the NO donor molsidomine (2 and 4mg/kg) and L-DOPA (12.5 and 25mg/kg) on rotational behavior and monoamine metabolism in the striatum (STR) and substantia nigra (SN) of unilaterally 6-OHDA-lesioned rats. Chronic administration of molsidomine at a dose of 2mg/kg jointly with 25mg/kg of L-DOPA significantly decreased the number of contralateral rotations when compared to L-DOPA alone. Other combinations of the examined drug doses were less effective. The tissue DA levels in the ipsilateral STR and SN after the last chronic doses of molsidomine (2mg/kg) and L-DOPA (12.5 or 25mg/kg), were significantly higher than after L-DOPA alone. Chronic L-DOPA treatment alone or jointly with a lower dose of molsidomine decreased 5-HT levels and accelerated its catabolism in the examined structures. However, combination of a higher dose of molsidomine with L-DOPA (25mg/kg) did not reduce 5-HT content while its catabolism was less intensive. The obtained results show that low doses of molsidomine can modulate rotational behavior and tissue DA and 5-HT concentrations in the STR and SN of 6-OHDA-lesioned rats treated chronically with L-DOPA.
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Affiliation(s)
- Elżbieta Lorenc-Koci
- Department of Neuro-Psychopharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12, Smętna St., PL-31-343 Kraków, Poland.
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West AR, Tseng KY. Nitric Oxide-Soluble Guanylyl Cyclase-Cyclic GMP Signaling in the Striatum: New Targets for the Treatment of Parkinson's Disease? Front Syst Neurosci 2011; 5:55. [PMID: 21747761 PMCID: PMC3129139 DOI: 10.3389/fnsys.2011.00055] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 06/16/2011] [Indexed: 11/13/2022] Open
Abstract
Striatal nitric oxide (NO)-producing interneurons play an important role in the regulation of corticostriatal synaptic transmission and motor behavior. Striatal NO synthesis is driven by concurrent activation of NMDA and dopamine (DA) D1 receptors. NO diffuses into the dendrites of medium-sized spiny neurons which contain high levels of NO receptors called soluble guanylyl cyclases (sGC). NO-mediated activation of sGC leads to the synthesis of the second messenger cGMP. In the intact striatum, transient elevations in intracellular cGMP primarily act to increase neuronal excitability and to facilitate glutamatergic corticostriatal transmission. NO–cGMP signaling also functionally opposes the inhibitory effects of DA D2 receptor activation on corticostriatal transmission. Not surprisingly, abnormal striatal NO–sGC–cGMP signaling becomes apparent following striatal DA depletion, an alteration thought to contribute to pathophysiological changes observed in basal ganglia circuits in Parkinson's disease (PD). Here, we discuss recent developments in the field which have shed light on the role of NO–sGC–cGMP signaling pathways in basal ganglia dysfunction and motor symptoms associated with PD and l-DOPA-induced dyskinesias.
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Affiliation(s)
- Anthony R West
- Department of Neuroscience, The Chicago Medical School, Rosalind Franklin University of Medicine and Science North Chicago, IL, USA
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Galati S, D'angelo V, Scarnati E, Stanzione P, Martorana A, Procopio T, Sancesario G, Stefani A. In vivo electrophysiology of dopamine-denervated striatum: focus on the nitric oxide/cGMP signaling pathway. Synapse 2008; 62:409-20. [PMID: 18361439 DOI: 10.1002/syn.20510] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Within the striatum, the gaseous neurotransmitter nitric oxide (NO) is produced by a subclass of interneurons containing the neuronal NO synthase (nNOS). NO promotes the second messenger cGMP through the activation of the soluble guanyl cyclase (sGC) and plays a crucial role in the integration of glutamate (GLU) and DA transmission. The aim of this study was to characterize the impact of 6-hydroxyDA (6-OHDA) lesion of the rat nigrostriatal pathway on NO/cGMP system. In vivo extracellular single units recordings were performed under urethane anesthesia to avoid any potentially misleading contributions of cortically-driven changes on endogenous NO. Hence, no electrical extrastriatal stimulation was performed and great attention was paid to the effects of 3-morpholinosydnonimine (SIN-1, a NO donor), N(G)-nitro-L-arginine methyl ester (L-NAME, a nonselective NOS inhibitor) and Zaprinast (a PDE inhibitor) delivered by iontophoresis upon the main striatal phenotypes. The latter were operationally distinguished in silent medium spiny-like neurons (MSN), with negligible spontaneous activity but displaying glutamate-induced firing discharge at rest and spontaneously active neurons (SAN), representing to a large extent nonprojecting interneurons. SANs were excited by SIN-1 and Zaprinast while MSNs showed a clear inhibition during local iontophoretic application of SIN-1 and Zaprinast. In 6-OHDA animals, SIN-1-induced excitation in SANs was significantly increased (on the contrary, the inhibitory effect of L-NAME was less effective). Interestingly, in DA-denervated animals, a subclass of MSNs (40%) displayed a peculiar excitatory response to SIN-1. These findings support the notion of an inhibitory modulatory role exerted by endogenous NO on control striatal projection cells. In addition, these findings suggest a functional cross-talk between NO, spontaneously active interneurons, and projection neurons that becomes critical in the parkinsonian state.
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Affiliation(s)
- Salvatore Galati
- Division of Neurology, Department of Neuroscience, University of Rome Tor Vergata, Rome, Italy
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Dzoljić E, Nesić Z, Stojanović R, Vucković S, Todorović Z, Prostran M. [Effects of new nitric oxide synthase inhibitors on spontaneous locomotor activity]. MEDICINSKI PREGLED 2006; 59:436-41. [PMID: 17345819 DOI: 10.2298/mpns0610436d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
INTRODUCTION New nitric oxide synthase (NOS) inhibitors: 3-bromo-7-nitroindazole (3-Br-7-NI), 1-(2-trifluoromethylphenyl) imidazole (TRIM), S-methyl-L-thiocitrulline (S-Me-TC) and 7-nitroindazole (7-NI) reduce spontaneous locomotor activity in mice. MATERIAL AND METHODS In order to elucidate central effects of NOS inhibitors on locomotor activity, the influence of 7-NI on electroencephalographic (EEG) power spectrum in rats was investigated. RESULTS 7-NI reduced the EEG power density in all frequency bands in rats, suggesting a depression of the central neuronal activity. The electrophysiologic power was most reduced in the range of 7-9 Hz of the rhythmic slow activity (theta rhythm), which is in accordance with decreased locomotor activity observed following administration of NOS inhibitors. CONCLUSION The present results indicate that nitric oxide exerts an excitatory effect on central neuronal structures involved in regulation of locomotion.
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Affiliation(s)
- Eleonora Dzoljić
- Klinicki centar Srbije, Beograd, Institut za neurologiju, Medicinski fakultet, Beograd
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Sammut S, Dec A, Mitchell D, Linardakis J, Ortiguela M, West AR. Phasic dopaminergic transmission increases NO efflux in the rat dorsal striatum via a neuronal NOS and a dopamine D(1/5) receptor-dependent mechanism. Neuropsychopharmacology 2006; 31:493-505. [PMID: 16012530 DOI: 10.1038/sj.npp.1300826] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dysfunctional neurotransmission within striatal networks is believed to underlie the pathophysiology of several neurological and psychiatric disorders. Nitric oxide (NO)-producing interneurons have been shown to play a critical role in modulating striatal synaptic transmission. These interneurons receive synaptic contacts from midbrain dopamine (DA) neurons and may be regulated by DA receptor activation. In the current study, striatal NO efflux was measured in anesthetized male rats using an NO-selective electrochemical microsensor and the role of DA in modulating NO synthase (NOS) activity was assessed during electrical or chemical (bicuculline) stimulation of the substantia nigra (SN). Electrical stimuli were patterned to approximate the natural single spike or burst firing activity of midbrain DA neurons. Electrical stimulation of the SN at low frequencies induced modest increases in striatal NO efflux. In contrast, train stimulation of the SN robustly increased NO efflux in a stimulus intensity-dependent manner. NO efflux evoked by SN stimulation was similar in chloral hydrate- and urethane-anesthetized rats. The facilitatory effect of train stimulation on striatal NO efflux was transient and attenuated by systemic administration of the neuronal NOS inhibitor 7-nitroindazole and the nonselective NOS inhibitor methylene blue. Moreover, the increase in NO efflux observed during chemical and train stimulation of the SN was attenuated following systemic administration of the DA D(1/5) receptor antagonist SCH 23390. SCH 23390 also blocked NO efflux induced by systemic administration of the D(1/5) agonist SKF 81297. These results indicate that neuronal NOS is activated in vivo by nigrostriatal DA cell burst firing via a DA D(1/5)-like receptor-dependent mechanism.
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Affiliation(s)
- Stephen Sammut
- Department of Neuroscience, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
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West AR, Grace AA. The nitric oxide-guanylyl cyclase signaling pathway modulates membrane activity States and electrophysiological properties of striatal medium spiny neurons recorded in vivo. J Neurosci 2004; 24:1924-35. [PMID: 14985433 PMCID: PMC6730403 DOI: 10.1523/jneurosci.4470-03.2004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nitric oxide (NO)-releasing interneurons are believed to regulate the activity of striatal medium spiny neurons (MSNs) that contain the NO effector enzyme guanylyl cyclase (GC). The involvement of NO-GC signaling in modulating steady-state membrane activity of striatal MSNs was examined using in vivo intracellular recordings in rats. Intrastriatal infusion of a neuronal NO synthase inhibitor or a NO scavenger via reverse microdialysis consistently decreased the amplitude of spontaneously occurring depolarized plateau potentials (up events). Intrastriatal infusion of a NO scavenger also decreased the amplitude of EPSPs evoked during electrical stimulation of the orbital prefrontal cortex. The effect of the NO scavenger on spontaneous up events was partially reversed by coperfusion with a cell-permeable cGMP analog. Intracellular injection of MSNs with a soluble GC inhibitor resulted in large decreases in the following: (1) spontaneous up-event amplitude, (2) responsiveness to depolarizing current, (3) action potential amplitude, and (4) input resistance. These effects were partially reversed by coinjection of cGMP. Conversely, intracellular injection of a phosphodiesterase inhibitor increased MSN neuron membrane excitability. These results indicate that, in the intact animal, the NO signaling pathway exerts a powerful tonic modulatory influence over the membrane activity of striatal MSNs via the activation of GC and stimulation of cGMP production.
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Affiliation(s)
- Anthony R West
- Department of Neuroscience, Finch University of Health Sciences/The Chicago Medical School, North Chicago, Illinois 60064, USA
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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.
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Affiliation(s)
- Anthony R West
- Department of Neuroscience, 446 Crawford Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Mancuso F, Porta R, Calignano A, Di Pierro P, Sommella MG, Esposito C. Substance P and its transglutaminase-synthesized spermine derivative elicit yawning behavior via nitric oxide in rats. Peptides 2001; 22:1453-7. [PMID: 11514028 DOI: 10.1016/s0196-9781(01)00465-x] [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] [Indexed: 11/27/2022]
Abstract
Previously, we showed that intranigrostriatal injection of substance P (SP) cause behavioral changes in rats. Those effects, such as locomotion and food intake, resulted related to catecholamines release modulated by nitric oxide [18]. Here we report that intranigrostriatal injection of SP elicited yawning in rats. Moreover, since in previous studies we demonstrated that transglutaminase-synthesized gamma-(glutamyl5)spermine derivative of SP (Spm-SP) could be a useful tool in differentiating NK1 receptors [5,19,26], we reports the effects of injecting the selective septide-sensitive NK1 receptor agonist Spm-SP into the nigrostriatal region of the rat brain on yawning. The administration of L-N(omega)-nitroarginine methyl ester, a NO-synthase inhibitor, stereospecifically reduced in a dose related manner both SP and Spm-SP-induced yawning. In contrast, L-arginine pretreatment prevented the effect of NO-synthase inhibitor. Moreover, the NK1 antagonist RP,67580 blocked yawning behavior induced by both SP and Spm-SP, whereas the pretreatment with systemic reserpine determined its increase. The administration of NO-synthase inhibitor resulted ineffective in reducing SP and Spm-SP-induced yawns in reserpinized rats. Finally, yawns elicited by SP or Spm-SP were blocked when rats were treated with scopolamine but not with methylscopolamine. These results indicate that yawning induced in rats by SP injection is dependent upon endogenous dopamine levels in brain nigrostriatal area. Moreover, we demonstrate, by using Spm-SP, that septide-sensitive NK1 receptor are specifically involved in yawning behavior.
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Affiliation(s)
- F Mancuso
- Department of Experimental Pharmacology, University of Naples, Federico II,, Naples, Italy
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Baretta IP, Assreuy J, De Lima TC. Nitric oxide involvement in the anxiogenic-like effect of substance P. Behav Brain Res 2001; 121:199-205. [PMID: 11275297 DOI: 10.1016/s0166-4328(01)00165-6] [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: 11/21/2022]
Abstract
This study investigates whether nitric oxide (NO) is involved in the anxiogenic profile of action of substance P (SP) in mice in the elevated plus-maze (EPM). Adult Swiss mice were injected with NOS inhibitors such as L-NOARG (20 nmol/kg) i.p., L-NAME (3 nmol per site), 7-NI (0.25 nmol per site) i.c.v. or vehicle (NaCl 0.9% i.p. or PBS i.c.v.). About 30 min (i.p. pretreatment) or 5 min later (i.c.v. pretreatment), the animals received i.c.v. injections of SP (10 pmol) or phosphate buffered saline (PBS) (2 microl). Afterwards, they were observed in the EPM. SP per se reduced the time spent on open arms, an anxiogenic-like effect. This effect was reverted by different NOS inhibitors and the NO donor. NOS inhibitors had no influence on the EPM parameters but the NO-releasing compound SNAP, as well as its parent thiol NAP, increased the animals' locomotor activity. 8-Br-cGMP (20 nmol), a permeable cGMP analog, promoted an anxiogenic-like effect per se and enhanced the SP effect on the EPM. Altogether, these results suggest a putative NO role in the mediation of the anxiogenic-like effect of SP.
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Affiliation(s)
- I P Baretta
- Department of Pharmacology, Universidade Paranaense, Umuarama PR, Brazil
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Dzoljic E, De Vries R, Dzoljic MR. New and potent inhibitors of nitric oxide synthase reduce motor activity in mice. Behav Brain Res 1997; 87:209-12. [PMID: 9331489 DOI: 10.1016/s0166-4328(97)02281-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Potent inhibitors of nitric oxide synthase (NOS), 3-bromo-7-nitro indazole, 1-(2-trifluoromethylphenyl)imidazole, S-methyl-L-thiocitrulline and 7-nitro indazole, reduced locomotion in mice. These results suggest that activity of NOS and corresponding NO release are of importance for normal locomotion.
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Affiliation(s)
- E Dzoljic
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, The Netherlands
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Abstract
The possible role of nitric oxide (NO) in CGRP-induced passive avoidance, active avoidance, and open field behavior was tested in rats. A specific NO synthase inhibitor, N omega-nitro-L-arginine (L-NA), was used to disrupt NO synthesis. ICV administration of 5 micrograms of L-NA reversed the action of CGRP in passive and active avoidance tests. In an open field, L-NA prevented the action of CGRP on locomotion and grooming. The inactive isomer D-NA had no effect on behavior of animals. The data suggest that NO might contribute to CGRP-induced behavior in rats.
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Affiliation(s)
- A Kovács
- Department of Pathophysiology, Albert Szent-Györgyi Medical University, Szeged, Hungary
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