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Engel JA, Pålsson E, Vallöf D, Jerlhag E. Ghrelin activates the mesolimbic dopamine system via nitric oxide associated mechanisms in the ventral tegmental area. Nitric Oxide 2023; 131:1-7. [PMID: 36513266 DOI: 10.1016/j.niox.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/08/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
Besides enhanced feeding, the orexigenic peptide ghrelin activates the mesolimbic dopamine system to cause reward as measured by locomotor stimulation, dopamine release in nucleus accumbens shell (NAcS), and conditioned place preference. Although the ventral tegmental area (VTA) appears to be a central brain region for this ghrelin-reward, the underlying mechanisms within this area are unknown. The findings that the gaseous neurotransmitter nitric oxide (NO) modulate the ghrelin enhanced feeding, led us to hypothesize that ghrelin increases NO levels in the VTA, and thereby stimulates reward-related behaviors. We initially demonstrated that inhibition of NO synthesis blocked the ghrelin-induced activation of the mesolimbic dopamine system. We then established that antagonism of downstream signaling of NO in the VTA, namely sGC, prevents the ability of ghrelin to stimulate the mesolimbic dopamine system. The association of ghrelin to NO was further strengthened by in vivo electrochemical recordings showing that ghrelin enhances the NO release in the VTA. Besides a GABAB -receptor agonist, known to reduce NO and cGMP, blocks the stimulatory properties of ghrelin. The present series of experiments reveal that ablated NO signaling, through pharmacologically inhibiting the production of NO and/or cGMP, prevents the ability of ghrelin to induced reward-related behaviors.
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Affiliation(s)
- Jörgen A Engel
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Erik Pålsson
- Institute of Neuroscience and Physiology, Department of Neurochemistry and Psychiatry, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Daniel Vallöf
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Elisabet Jerlhag
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
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Wu Z, Huang Y, Hu W, Ren L, Jiang P, Margolskee RF, Wang H, Feng S. Lipopolysaccharide-induced inflammation increases nitric oxide production in taste buds. Brain Behav Immun 2022; 103:145-153. [PMID: 35447301 PMCID: PMC10353706 DOI: 10.1016/j.bbi.2022.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/30/2022] [Accepted: 04/14/2022] [Indexed: 12/29/2022] Open
Abstract
Inducible nitric oxide synthase (iNOS) is expressed when cells are induced or stimulated by proinflammatory cytokines and/or bacterial lipopolysaccharide (LPS). iNOS is a downstream gene of the NF-κB pathway. Our previous studies demonstrated that five Nfkb genes are expressed in mouse taste epithelium and taste organoids. However, it is unclear whether activation of the NF-κB pathway could induce iNOS gene expression and increase nitric oxide (NO) production in taste buds. In this study, we investigated the expression of iNOS mRNA and protein after LPS stimulation. Our results showed that a subset of taste bud cells and taste neurons express iNOS proteins after LPS stimulation. In addition, isolated mouse taste epithelium can release NO after exposure to LPS ex vivo. In taste behavioral tests, the NO donor nitroprusside enhanced mouse aversive responses to salty, bitter, and sour taste compounds. The enhanced aversive responses were especially strong for salty taste. In conclusion, our results suggest that iNOS and NO may play a role in the inflammation-associated taste disturbances.
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Affiliation(s)
- Zhizhongbin Wu
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, Chongqing, China
| | - Yilin Huang
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, Chongqing, China
| | - Weiqing Hu
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, Chongqing, China
| | - Liyin Ren
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, Chongqing, China
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | | | - Hong Wang
- Monell Chemical Senses Center, Philadelphia, PA, USA.
| | - Shan Feng
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, Chongqing, China; Monell Chemical Senses Center, Philadelphia, PA, USA.
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Yunusoğlu O. Rewarding effect of ethanol-induced conditioned place preference in mice: Effect of the monoterpenoid linalool. Alcohol 2022; 98:55-63. [PMID: 34800613 DOI: 10.1016/j.alcohol.2021.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 11/06/2021] [Accepted: 11/12/2021] [Indexed: 11/01/2022]
Abstract
Alcohol addiction is a chronic relapsing disease that is progressive and has severe detrimental health outcomes. The use of natural products has become popular for the treatment of side effects of drugs and substance abuse. Linalool is a monoterpenoid that exhibits several effects on the central nervous system. Linalool was identified to have beneficial effects on different mechanisms that are relevant in drug addiction or substance use disorder. The primary aim of the present study was to evaluate the therapeutic effect of linalool on the rewarding properties of alcohol in mice. Conditioned place preference (CPP) was established by intraperitoneal (i.p.) injection of ethanol (2 g/kg) during an 8-day conditioning trial. The effects of acamprosate and linalool on the rewarding properties of ethanol were tested in mice who received linalool (12.5, 25, and 50 mg/kg, i.p.) and acamprosate (300 mg/kg, i.p.) 30 min before each ethanol injection. CPP was extinguished by repeated testing, throughout which conditioned mice were administered daily linalool. Mice were lastly examined for reinstatement provoked by i.p. administration of single low-dose ethanol (0.4 g/kg, i.p.). Treatment with linalool reduced the acquisition and reinstatement, and precipitated the extinction of ethanol-induced CPP in mice. Acquisition and reinstatement of alcohol-induced CPP were significantly reduced by acamprosate, which also precipitated extinction. Ethanol alone and the combination with linalool or acamprosate did not alter locomotor activity. The results of this study suggest that linalool may have pharmacological effects for the treatment of alcohol addiction. In addition, further investigation is required to fully explore the benefits and possible adverse effects of linalool on alcohol addiction.
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Nitric Oxide Signaling Pathway in Ventral Tegmental Area is Involved in Regulation of 7,8-Dihydroxyflavone on Alcohol Consumption in Rats. Mol Neurobiol 2021; 59:35-46. [PMID: 34618330 DOI: 10.1007/s12035-021-02575-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 09/15/2021] [Indexed: 01/12/2023]
Abstract
We recently reported that intraperitoneal injection of 7,8-dihydroxyflavone (7,8-DHF), a brain-derived neurotrophic factor-mimicking small compound, could attenuate alcohol-related behaviors in a two-bottle choice ethanol consumption procedure (IA2BC) in rats via tropomyosin receptor kinase B in the ventral tegmental area (VTA), which is closely related to alcohol use disorder. However, the detailed mechanisms underlying the regulation of 7,8-DHF on alcohol drinking behavior remain elusive. In this study, we determined the role of nitric oxide (NO), a pleiotropic signaling molecule, in the VTA in the action of 7,8-DHF upon alcohol drinking behavior. Intermittent alcohol exposure led to the overexpression of NO in the VTA, especially 72 h after withdrawal from four weeks of ethanol exposure in IA2BC rats. A higher amount of alcohol intake was also found at the same time point, consistent with the overexpression of NO in the VTA. Microinjection of NG-Nitro-l-Arginine Methyl Ester, (NO synthase inhibitor) or 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NO scavenger) into the VTA inhibited alcohol intake, whereas application of S-Nitroso-N-acetyl-DL-penicillamine (SNAP, the NO donor) in the VTA further enhanced alcohol consumption in IA2BC rats. Interestingly, either 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (a sGC inhibitor) or KT5823 [a selective protein kinase G (PKG) inhibitor] blocked NO's enhancing effect on ethanol intake. Intraperitoneal injection of 7,8-DHF reduced the overexpression of NO; SNAP microinjected into the VTA reversed the inhibitory effects of 7,8-DHF on alcohol consumption. Our findings suggest that NO-cGMP-PKG might be involved in regulation of 7,8-DHF on alcohol consumption in IA2BC rats.
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Yunusoğlu O. Resveratrol impairs acquisition, reinstatement and precipitates extinction of alcohol-induced place preference in mice. Neurol Res 2021; 43:985-994. [PMID: 34210247 DOI: 10.1080/01616412.2021.1948749] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Alcohol abuse causes several neurological disorders. Resveratrol is a natural polyphenol that occurs as a phytoalexin. In different studies, it has been investigated that resveratrol has positive effects on various mechanisms that are important in drug addiction or substance use disorder. The objective of the present study was to examine the effect of resveratrol on alcohol-induced conditioned place preference (CPP) in mice. METHODS CPP was induced by intraperitoneal (i.p.) administration of ethanol (2 g/kg) in an 8-day conditioning program. The influence of reference drug, acamprosate and resveratrol on the rewarding properties of ethanol was tested in mice given treatment of acamprosate (300 mg/kg, i.p.) and resveratrol (25, 50, and 75 mg/kg, i.p.) 30 minutes prior to ethanol administration. Once established, CPP was extinguished by repeated testing, through which conditioned mice were administered acamprosate, various doses of resveratrol or saline daily. Subsequently, the potency of acamprosate and resveratrol in preventing reinstatement of CPP provoked by priming with low-dose ethanol (0.4 g/kg, i.p.) was also evaluated. RESULTS The present findings confirm that resveratrol impairs acquisition, reinstatement and precipitates the extinction of preference for alcohol-induced CPP. Resveratrol presented a similar effect in the CPP phases to the acamprosate. CONCLUSIONS The effect of resveratrol on ethanol-induced CPP in mice demonstrated for the first time. As a conclusion, these findings may shed light on the fact that resveratrol can be utilized as an agent which is potentially beneficial to prevent the various harmful effects of ethanol, however, more research is needed to completely elucidate this attribute.
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Affiliation(s)
- Oruç Yunusoğlu
- Department of Pharmacology, Faculty of Medicine, Van Yuzuncu Yil University, Van, Turkey
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Increased brain nitric oxide levels following ethanol administration. Nitric Oxide 2015; 47:52-7. [PMID: 25819134 DOI: 10.1016/j.niox.2015.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 03/10/2015] [Accepted: 03/13/2015] [Indexed: 01/14/2023]
Abstract
Nitric oxide is a ubiquitous messenger molecule, which at elevated concentrations has been implicated in the pathogenesis of several neurological disorders. Its role in oxidative stress, attributed in particular to the formation of peroxynitrite, proceeds through its high affinity for the superoxide radical. Alcoholism has recently been associated with the induction of oxidative stress, which is generally defined as a shift in equilibrium between pro-oxidant and anti-oxidant species in the direction of the former. Furthermore, its primary metabolite acetaldehyde, has been extensively associated with oxidative damage related toxic effects following alcohol ingestion. The principal objective of this study was the application of long term in vivo electrochemistry (LIVE) to investigate the effect of ethanol (0.125, 0.5 and 2.0 g kg(-1)) and acetaldehyde (12.5, 50 and 200 mg kg(-1)) on NO levels in the nucleus accumbens of freely moving rats. Systemic administrations of ethanol and acetaldehyde resulted in a dose-dependent increases in NO levels, albeit with very differing time courses. Subsequent to this the effect on accumbal NO levels, of subjecting the animal to different drug combinations, was also elucidated. The nitric oxide synthase inhibitor L-NAME (20 mg kg(-1)) and acetaldehyde sequestering agent D-penicillamine (50 mg kg(-1)) both attenuated the increase in NO levels following ethanol (1 g kg(-1)) administration. Conversely, the alcohol dehydrogenase inhibitor 4-methylpyrazole (25 mg kg(-1)) and catalase inhibitor sodium azide (10 mg kg(-1)) potentiated the increase in NO levels following ethanol administration. Finally, dual inhibition of aldehyde dehydrogenase and catalase by cyanamide (25 mg kg(-1)) caused an attenuation of ethanol effects on NO levels. Taken together these data highlight a robust increase in brain NO levels following systemic alcohol administration which is dependent on NO synthase activity and may involve both alcohol- and acetaldehyde-dependent mechanisms.
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March SM, Abate P, Spear NE, Molina JC. The role of acetaldehyde in ethanol reinforcement assessed by Pavlovian conditioning in newborn rats. Psychopharmacology (Berl) 2013. [PMID: 23196716 DOI: 10.1007/s00213-012-2920-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RATIONALE Animal studies indicate that central acetaldehyde, dependent on catalase metabolism of ethanol (EtOH), modulates ethanol reinforcement. Brain catalase activity and acetaldehyde (ACD) production are significantly higher in rat pups compare d with adults. Interestingly, infant rats show high EtOH affinity for alcohol consumption and are particularly sensitive to the drug's reinforcing effects. OBJECTIVES We tested whether central ACD is necessary and sufficient to induce appetitive conditioning in newborn rats through the artificial nipple technique. METHODS Vehicle, EtOH (100 mg%), and acetaldehyde (0.35 μmol) were administered into the cisterna magna (1 μl). Half of the animals also received a central administration of 75 μg (experiment 1) or 40 μg of D-penicillamine (experiment 2). Afterwards, pups were exposed to an olfactory cue (conditioned stimulus). One hour later, neonates were tested with an artificial nipple in the presence of the conditioned cue. Nipple attachment duration, mean grasp duration, and number of nipple disengagements served as dependent variables. RESULTS Positive responses to the scented nipple occurred in neonates conditioned with EtOH or ACD (experiments 1 and 2). In experiment 1, there were indications that D-penicillamine weakened the reinforcing effects of EtOH and ACD. In experiment 2, D-penicillamine (40 μg) significantly inhibited appetitive conditioned responses dependent upon EtOH or ACD. CONCLUSIONS Appetitive conditioning was observed when employing either central EtOH or ACD as unconditioned stimuli. Central abduction of ACD inhibited conditioned appetitive responsiveness to the surrogate nipple. Central ACD is involved in the determination or modulation of EtOH's motivational properties during early stages in development.
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Affiliation(s)
- Samanta M March
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET), P.O. BOX 389, Friuli 2434, 5016 Córdoba, Argentina.
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Spanagel R. Alcoholism: A Systems Approach From Molecular Physiology to Addictive Behavior. Physiol Rev 2009; 89:649-705. [DOI: 10.1152/physrev.00013.2008] [Citation(s) in RCA: 491] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Alcohol consumption is an integral part of daily life in many societies. The benefits associated with the production, sale, and use of alcoholic beverages come at an enormous cost to these societies. The World Health Organization ranks alcohol as one of the primary causes of the global burden of disease in industrialized countries. Alcohol-related diseases, especially alcoholism, are the result of cumulative responses to alcohol exposure, the genetic make-up of an individual, and the environmental perturbations over time. This complex gene × environment interaction, which has to be seen in a life-span perspective, leads to a large heterogeneity among alcohol-dependent patients, in terms of both the symptom dimensions and the severity of this disorder. Therefore, a reductionistic approach is not very practical if a better understanding of the pathological processes leading to an addictive behavior is to be achieved. Instead, a systems-oriented perspective in which the interactions and dynamics of all endogenous and environmental factors involved are centrally integrated, will lead to further progress in alcohol research. This review adheres to a systems biology perspective such that the interaction of alcohol with primary and secondary targets within the brain is described in relation to the behavioral consequences. As a result of the interaction of alcohol with these targets, alterations in gene expression and synaptic plasticity take place that lead to long-lasting alteration in neuronal network activity. As a subsequent consequence, alcohol-seeking responses ensue that can finally lead via complex environmental interactions to an addictive behavior.
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Krecsmarik M, Izbéki F, Bagyánszki M, Linke N, Bódi N, Kaszaki J, Katarova Z, Szabó A, Fekete E, Wittmann T. Chronic ethanol exposure impairs neuronal nitric oxide synthase in the rat intestine. Alcohol Clin Exp Res 2006; 30:967-73. [PMID: 16737454 DOI: 10.1111/j.1530-0277.2006.00110.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Nitric oxide (NO), synthesized by neuronal (nNOS), endothelial (eNOS), and inducible (iNOS) nitric oxide synthases, plays an essential role in the physiological functions of the gastrointestinal (GI) tract. Chronic ethanol intake has been shown to interfere with several of these physiological functions, leading to the pathological alterations observed in alcoholic individuals. Our aim therefore was to investigate the effects of chronic ethanol consumption on NOS isoforms in different GI segments. METHODS Rats received either 20% aqueous ethanol solution or water for 8 weeks. Tissue samples of the duodenum, jejunum, ileum, and colon of the rats were used for measurement of the NOS activity, protein content, and nNOS immunohistochemistry. Anti-HuC/D immunohistochemistry was used to determine the total number of neurons. RESULTS Measurement of the physiological constitutive NOS (cNOS) activity revealed a 20 times higher activity in the colon than in the small intestine and after chronic ethanol treatment demonstrated a significant decrease in the jejunum, ileum, and colon, while in the duodenum it remained unchanged compared with the control group. The physiological iNOS activity was higher in the ileum and colon than in the duodenum and jejunum, and these levels were not significantly affected by ethanol. Neuronal nitric oxide synthase immunohistochemistry revealed a significant decrease in the numbers of immunostained cells in all investigated intestinal segments, while the total number of myenteric neurons remained constant. The nNOS protein content measured by Western blotting indicated a significant decrease in the colon after ethanol consumption, while in other intestinal segments change was not detectable. CONCLUSIONS This study has demonstrated for the first time that chronic ethanol consumption has a differential effect on NOS activity, NOS protein content, and the number of nitrergic neurons in different intestinal segments, suggesting that chronic ethanol administration affects the NO pathways in the enteric nervous system.
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Affiliation(s)
- Monika Krecsmarik
- Department of Zoology and Cell Biology, University of Szeged, Szeged, Hungary.
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Green KL, Gatto GJ, Grant KA. The Nitric Oxide Synthase Inhibitor l-NAME (N
ω-Nitro-L-Arginine Methyl Ester) Does Not Produce Discriminative Stimulus Effects Similar to Ethanol. Alcohol Clin Exp Res 2006; 21:483-488. [DOI: 10.1111/j.1530-0277.1997.tb03794.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Font L, Miquel M, Aragon CMG. Prevention of Ethanol-Induced Behavioral Stimulation by d-Penicillamine: A Sequestration Agent for Acetaldehyde. Alcohol Clin Exp Res 2006; 29:1156-64. [PMID: 16046870 DOI: 10.1097/01.alc.0000171945.30494.af] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND D-Penicillamine, a sulfhydryl amino acid derived from penicillin, is a highly selective agent for sequestering in vivo acetaldehyde, the first metabolic product of ethanol. A substantial amount of research supports the idea that brain acetaldehyde, produced by central ethanol metabolism, plays a key role in determining some of the behavioral effects of ethanol administration. This study addressed two questions. First, we tested if D-penicillamine was able to modify the depressant effects of acetaldehyde on behavior. Second, we studied the effect of D-penicillamine on ethanol-induced behavioral stimulation. METHODS Mice were pretreated with 75.00 mg/kg of D-penicillamine, and 30 min later, they received acetaldehyde at 0, 100, 200, or 300 mg/kg intraperitoneally. Different groups of animals were treated with 0.0, 37.5, 75, 150, or 300 mg/kg of D-penicillamine simultaneously 30, 90, 150, or 210 min before the intraperitoneal administration of saline or 1.2, 1.8, 2.4, 3.0, or 3.6 g/kg of ethanol, respectively. The specificity of D-penicillamine effects was addressed using two drugs: cocaine (4 mg/kg) and caffeine (15 mg/kg). RESULTS Our results revealed that behavioral depression caused by acetaldehyde (200 and 300 mg/kg) could be attenuated by D-penicillamine treatment. In addition, D-penicillamine was also effective in lowering behavioral locomotion induced by ethanol (1.8 and 2.4 g/kg), without altering spontaneous locomotor activity. This sulfhydryl amino acid specifically modified the effect of ethanol on locomotion because cocaine- or caffeine-induced locomotion was unaffected. In addition, blood ethanol levels were not different between D-penicillamine- and saline-pretreated mice. CONCLUSIONS Behavioral effects produced by acetaldehyde and ethanol are blocked when animals are treated with D-penicillamine, an effective sequestration agent for acetaldehyde. These results suggest that some of the psychopharmacological effects, classically attributed to ethanol, could be mediated by its first metabolite, acetaldehyde.
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Affiliation(s)
- Laura Font
- Area de Psicobiología, Universitat Jaume I, Castelló, Spain
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Font L, Aragon CMG, Miquel M. Voluntary ethanol consumption decreases after the inactivation of central acetaldehyde by d-penicillamine. Behav Brain Res 2006; 171:78-86. [PMID: 16621047 DOI: 10.1016/j.bbr.2006.03.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Revised: 03/10/2006] [Accepted: 03/15/2006] [Indexed: 10/24/2022]
Abstract
Acetaldehyde, the first metabolite of ethanol, may mediate some ethanol-induced effects. Previous research in our laboratory has shown that D-penicillamine, an inactivation agent for acetaldehyde, is effective in decreasing locomotor stimulation and conditioned place preference induced by ethanol in mice. In the present study, the effects of D-penicillamine on the voluntary consumption of ethanol were assessed. Male rats were offered ethanol under restricted access, without food or water deprivation. Daily availability of ethanol was limited to a 15-min period in the home cages. When the response for 10% ethanol was stable, rats received an intraperitoneal (IP) injection of D-penicillamine (0, 25, 50 or 75 mg/kg) over a 5-day period, given 30 min before exposure to ethanol. In a second study we determined the specificity of D-penicillamine effects (50 mg/kg) on voluntary sucrose consumption (3%). Another study was conducted to evaluate whether IP D-penicillamine (50 mg/kg) alters taste reactivity responses. In the final experiment, rats were treated with intracerobroventricular (ICV) infusions of D-penicillamine (75 microg) for 5 days before drinking ethanol or sucrose. D-Penicillamine was found to reduce ethanol intake in a dose-dependent manner. Sucrose consumption was also affected by this thiol amino acid. We also demonstrated that D-penicillamine produced changes in the ingestive and flavor properties of sucrose and ethanol, measured by means of a taste reactivity test. When D-penicillamine was administered ICV, only voluntary ethanol consumption was modified. These findings indicate that the central inactivation of acetaldehyde blocks ethanol intake in rats, and suggest that acetaldehyde plays a key role in the motivational properties of ethanol.
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Affiliation(s)
- Laura Font
- Area de Psicobiología, Universitat Jaume I, Castelló, Spain
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Hofmann F, Feil R, Kleppisch T, Schlossmann J. Function of cGMP-Dependent Protein Kinases as Revealed by Gene Deletion. Physiol Rev 2006; 86:1-23. [PMID: 16371594 DOI: 10.1152/physrev.00015.2005] [Citation(s) in RCA: 327] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Over the past few years, a wealth of biochemical and functional data have been gathered on mammalian cGMP-dependent protein kinases (cGKs). In mammals, three different kinases are encoded by two genes. Mutant and chimeric cGK proteins generated by molecular biology techniques yielded important biochemical knowledge, such as the function of the NH2-terminal domains of cGKI and cGKII, the identity of the cGMP-binding sites of cGKI, and the substrate specificity of the enzymes. Genetic approaches have proven especially useful for the analysis of the biological functions of cGKs. Recently, some of the in vivo targets and mechanisms leading to changes in neuronal adaptation, smooth muscle relaxation and growth, intestinal water secretion, bone growth, renin secretion, and other important functions have been identified. These data show that cGKs are signaling molecules involved in many biological functions.
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Affiliation(s)
- F Hofmann
- Institut für Pharmakologie und Toxicologie, Technische Universität München, Biedersteiner Strasse 29, D-80802 Munich, Germany.
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Davis RL, Syapin PJ. Interactions of alcohol and nitric-oxide synthase in the brain. ACTA ACUST UNITED AC 2005; 49:494-504. [PMID: 16269316 DOI: 10.1016/j.brainresrev.2005.01.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 12/08/2004] [Accepted: 01/24/2005] [Indexed: 11/30/2022]
Abstract
Nitric oxide (NO) is an important molecule associated with both physiological and pathological brain events. Three separate genes encode for nitric-oxide synthase (NOS), the rate-limiting enzyme in NO production, all of which are expressed within brain tissue. Effects of ethanol on NO production may be important to ethanol modification of brain function. Existing data indicate that alcohol exposure alters NOS expression and activity in the brain. Modulation of NOS is suggested to be involved in alcohol-induced behavioral modifications. Furthermore, alcohol-induced changes in NOS may alter immunocompetence, response to injury in the central nervous system, and may be involved in ethanol-mediated neurodegeneration and neurotoxicity. The extent and direction of change in NOS expression and activity depends on cell type and length of exposure. The mechanisms underlying these effects are only partially understood. Herein, the current understanding of the interactions of ethanol and NOS in the brain are discussed.
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Affiliation(s)
- Randall L Davis
- Department of Pharmacology/Physiology, Neuroinflammation Research Laboratory, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, USA.
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Abstract
OBJECTIVE Previous studies indicate that the nitric oxide (NO(.)) pathway is involved in the acute or chronic effects of ethanol on the central nervous system. However, direct evidence for the effect of ethanol on NO(.) production in vivo is lacking, and it is not clear whether it is inhibition or stimulation of the NO(.) pathway that contributes to the behavioral effects of ethanol. Herein the release of NO(.) in the rat striatum in vivo in response to NMDA receptor activation--the dominant mechanism controlling NO(.) formation-has been investigated after systemic or local injections of ethanol. METHODS NMDA-induced release of authentic NO(.) was measured directly in the striatum of urethane-anesthetized (1.2 g/kg intraperitoneally) male Sprague-Dawley rats by using a direct-current amperometric method coupled to an electrically modified carbon microelectrode. An injector cannula was implanted in the proximity of the electrode (250 microm apart) for focal drugs application. RESULTS Local application of NMDA (1 microl, 100 microM) produced a sharp and transient NO(.) signal. Systemic ethanol, 1 or 2.5 g/kg intraperitoneally, caused a long-lasting, dose-dependent inhibition of NMDA-induced NO(.) release to 12.2 +/- 5.9 and 6.4 +/- 3.7% of control, respectively, 60 min after ethanol administration. Dizocilpine (0.5 mg/kg intraperitoneally) mimicked the ethanol effect, inhibiting NO release to 1.6 +/- 0.66% of control. Local application of ethanol (1 microl, 2.5% v/v) in the striatum reduced the NMDA-induced response to 28.6 +/- 3.8% of control. Focal application of the competitive NMDA receptor antagonist D-(-)-2-amino-5-phosphonopentanoic acid (100 microM) or the nonselective NO synthase inhibitor L-N(G)-nitro-arginine methyl esther (100 microM) also caused inhibition of NMDA-induced NO(.) release to 2.4 +/- 0.7 and 4.3 +/- 0.9% of control, respectively. CONCLUSIONS Ethanol, at pharmacologically significant doses, strongly inhibits striatal NO(.) production and release apparently through inhibition of NMDA receptor function. Inhibition of NMDA receptor-mediated activation of the NO(.) pathway could be a primary neurobiological mechanism contributing to the effects of ethanol.
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Affiliation(s)
- Zvani L Rossetti
- Department of Neuroscience and CNR Institute of Neuroscience, University of Cagliari, Cittadella di Monserrato, 09042 Monserrato, Italy.
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Werner C, Raivich G, Cowen M, Strekalova T, Sillaber I, Buters JT, Spanagel R, Hofmann F. Importance of NO/cGMP signalling via cGMP-dependent protein kinase II for controlling emotionality and neurobehavioural effects of alcohol. Eur J Neurosci 2005; 20:3498-506. [PMID: 15610182 DOI: 10.1111/j.1460-9568.2004.03793.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclic GMP is a second messenger for nitric oxide (NO) that acts as a mediator for many different physiological functions. The cGMP-dependent protein kinases (cGKs) mediate cellular signalling induced by NO and cGMP. Here, we explored the localization of cGMP-dependent protein kinase type II (cGKII) in the mouse brain. In situ hybridization revealed high levels of cGKII mRNA in cerebral cortex, thalamic nuclei, hypothalamic nuclei, and in several basal forebrain regions including medial septum, striatum and amygdala. The close link to NO and the distribution pattern of cGKII suggested that this enzyme might be involved in emotional reactions and responses to drugs of abuse. Therefore, cGKII knockout animals (cGKII-/-) were compared with littermate controls in behavioural tests (i) for emotion-linked and (ii) for acute and chronic ethanol responses. Deletion of cGKII did not influence aggressive behaviour but led to enhanced anxiety-like behaviour. In terms of acute responses to ethanol, cGKII-/- mice were hyposensitive to hypnotic doses of ethanol as measured by the loss of righting reflex, without an alteration in their blood alcohol elimination. In a two-bottle free choice test, cGKII-/- mice showed elevated alcohol consumption. No taste differences to sweet solutions were observed compared to control animals. In summary, our data show that cGKII activity modulates anxiety-like behaviour and neurobehavioural effects of alcohol.
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Affiliation(s)
- Claudia Werner
- Institut für Pharmakologie und Toxikologie, Technische Universität München, Biedersteiner Strasse 29, 80802 München, Germany.
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17
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Abstract
The purpose of the current study was to ascertain whether ethyl nitrite could be detected in vitro from the reaction of ethanol with peroxynitrite, as well as after administration of ethanol to mice. Ethyl nitrite analyte was determined by using gas chromatography--mass spectrometry with headspace analysis with the use of a solid-phase microextraction device. Peroxynitrite was allowed to react with ethanol under a variety of conditions in vitro. Ethyl nitrite was generated when peroxynitrite was allowed to react with ethanol. Male, inbred short-sleep mice were injected intraperitoneally with either ethanol [5.2 g/kg; 15.0% (weight/volume) ethanol in saline] or a 50:50 mixture of deuterium-labeled ethanol (D5-ethanol) and ethanol. Blood samples, as well as whole brain and liver sections, were obtained from mice 30 min later for determination of ethanol, D5-ethanol, ethyl nitrite, and deuterium-labeled ethyl nitrite (D5-ethyl nitrite). Time courses for the appearance of ethyl nitrite in blood samples, as well as in whole brain and liver sections, obtained from mice were carried out. After ethanol administration, ethyl nitrite was detected and quantitated in mouse blood, brain, and liver. A small fraction of ethyl nitrite was present. When a 50:50 mixture of ethanol and D5-ethanol was given to animals, both ethyl nitrite and D5-ethyl nitrite were found in blood and brain in approximately the same ratio as that of ethanol and D5-ethanol. The level of D5-ethyl nitrite in liver was more than twice that of ethyl nitrite, indicating a possible isotope effect in the metabolism of ethyl nitrite. Ethyl nitrite is a new metabolite of ethanol in vivo. The mechanism of ethyl nitrite formation is most likely the reaction of ethanol with peroxynitrite generated in vivo from nitric oxide.
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Affiliation(s)
- Xin-Sheng Deng
- University of Colorado Health Sciences Center at Fitzsimons, School of Medicine, Alcohol Research Center and Department of Pharmacology, Mail Stop 8303, PO Box 6511, Aurora, CO 80045-0511, USA.
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Liu X, Weiss F. Nitric Oxide Synthesis Inhibition Attenuates Conditioned Reinstatement of Ethanol-Seeking, but Not the Primary Reinforcing Effects of Ethanol. Alcohol Clin Exp Res 2004; 28:1194-9. [PMID: 15318118 DOI: 10.1097/01.alc.0000134219.93192.00] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Nitric oxide (NO) signaling has been implicated in regulating aspects of the reinforcing and addictive actions of cocaine. These experiments were designed to examine whether NO-dependent neurotransmission also participates in mediating the addictive actions of another drug of abuse, ethanol, with emphasis on both the primary reinforcing effects of ethanol and the incentive motivational effects of ethanol-related contextual stimuli. METHODS Male Wistar rats were operantly trained to orally self-administer 10% (w/v) ethanol in daily 30-min sessions and to associate distinct discriminative stimuli with the availability of ethanol (S+) versus nonreward (S-). Rats were treated with the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 0, 10, or 40 mg/kg intraperitoneally) 30 min before self-administration tests that were conducted after establishment of stable levels of daily ethanol intake and conditioned reinstatement tests that were performed after extinction of ethanol-maintained operant responding. RESULTS L-NAME did not alter the primary reinforcing effects of ethanol in self-administration tests. In contrast, L-NAME dose-dependently attenuated the recovery of extinguished responding induced by the ethanol S in the absence of ethanol availability during reinstatement tests. CONCLUSIONS These results suggest that the NO system does not play a role in behavior reinforced directly by ethanol. However, the results implicate NO-dependent neurotransmission in alcohol-seeking responses elicited by drug-related contextual stimuli.
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Affiliation(s)
- Xiu Liu
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California, USA
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19
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Boyadjieva NI, Chen CP, Sarkar DK. Role of nitric oxide in alcohol alteration of beta-endorphin release from hypothalamic cells in primary cultures. Alcohol Clin Exp Res 2004; 27:1813-8. [PMID: 14634498 DOI: 10.1097/01.alc.0000093740.63754.0c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Nitric oxide (NO) mediates many pharmacological actions of ethanol. NO's role in regulating ethanol action on hypothalamic beta-endorphin (beta-EP) neurons is not established. METHODS In this study, we determined the role of NO in ethanol regulation of beta-EP release from primary cultures of rat fetal mediobasal hypothalamic cells. Real-time polymerase chain reaction was used for messenger RNA (mRNA) detection; radioimmunoassay was used for hormone measurements. RESULTS Acute ethanol treatment for 3 hr increased the release of beta-EP but reduced nitrite levels in the media of hypothalamic cells in primary cultures. In contrast, ethanol exposure for 48 hr reduced the release of beta-EP but increased the release of nitrite from these cells. Alcohol treatments altered the expression of neuronal NO synthase mRNA, but not inducible NO synthase mRNA, in a pattern similar to that of nitrite levels. Alcohol treatments blocked sodium nitroprusside-induced increases in the level of cellular cyclic guanidine monophosphate. The nonspecific NO blocker NG-nitro-l-arginine-methyl-esther, but not the inactive isomer N-nitro-d-arginine-methyl-esther (d-NAME), inhibited ethanol inhibitory actions on beta-EP release. CONCLUSIONS These results suggest that the cyclic guanidine monophosphate/NO pathway is involved in ethanol alteration of hypothalamic beta-EP release.
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Affiliation(s)
- Nadka I Boyadjieva
- Center for Alcohol Studies and Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick 08901-8525, USA
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20
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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.
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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
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21
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Affiliation(s)
- Gunter Schumann
- Molecular Genetics Laboratory, Department of Psychiatry, Central Institute of Mental Health, J5, D-68159 Mannheim, Germany.
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22
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Naassila M, Pierrefiche O, Beaugé FJ, Sébire N, Daoust M. Chronic ethanol exposure differentially regulates NOS1 mRNA levels depending on rat brain area. Neurosci Lett 2003; 338:221-4. [PMID: 12581836 DOI: 10.1016/s0304-3940(02)01417-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Several works have suggested a potential role for nitric oxide in alcohol-seeking behavior and we have recently shown that the specific blockade of the expression of the neuronal nitric oxide synthase (NOS1) decreases rat ethanol intake. Our previous results have also shown that chronic ethanol exposure has differential effect on the brain NOS activity depending on rat brain area. In the present study, we examine the effects of chronic administration of ethanol on the NOS1-mRNA levels measured with the competitive reverse transcriptase-polymerase chain reaction technique. Chronic administration of ethanol differentially regulated NOS1-mRNA levels depending on rat brain area. Chronic ethanol exposure had no effect on the NOS1-mRNA levels in frontal cortex, but decreased the NOS1-mRNA levels in hippocampus (P<0.01, 39% decrease) and induced a strong increase in striatum (P<0.01, 92% increase). These effects of ethanol were not affected by 7-nitro indazole (25 mg/kg, i.p. daily for 1 week) treatment. These data further support that NOS1 is regulated by chronic exposure to ethanol and that these effects are related to modifications of mRNA levels.
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Affiliation(s)
- Mickaël Naassila
- Université de Picardie Jules Verne, Faculté de Pharmacie, EA 2088 Environnement Toxique Périnatal-Adaptations Physiologiques et Comportementales, 1 rue des Louvels, 80000 Amiens, France.
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23
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Abstract
In the present study, we describe a new role of the neuronal nitric oxide synthase (nNOS) gene in the regulation of alcohol drinking behavior. Mice deficient in the nNOS gene (nNOS -/-) and wild-type control mice were submitted to a two-bottle free-choice procedure with either water or increasing concentrations of alcohol (2-16%) for 6 weeks. nNOS -/- mice did not differ in consumption and preference for low alcohol concentrations from wild-type animals; however, nNOS -/- mice consumed sixfold more alcohol from highly concentrated alcohol solutions than wild-type mice. Taste studies with either sucrose or quinine solutions revealed that alcohol intake in nNOS -/- and wild-type mice is associated, at least in part, with sweet solution intake but not with the taste of bitterness. When compared with wild-type mice, the nNOS -/- mice were found to be less sensitive to the sedative effects of ethanol as measured by shorter recovery time from ethanol-induced sleep and did not develop rapid tolerance to ethanol-induced hypothermia, although plasma ethanol concentrations were not significantly different from those of controls. Our findings contrast with previous reports that showed that nonselective NOS inhibitors decrease alcohol consumption. However, because alcohol consumption was suppressed in wild-type as well as nNOS -/- mice by the NOS inhibitor N(G)-nitro-L-arginine methyl ester, we conclude that the effect of nonselective NOS inhibitors on alcohol drinking is not mediated by nNOS. Other NOS isoforms, most likely in the periphery or other splice variants of the NOS gene, might contribute to the effect of nonselective NOS inhibitors on alcohol drinking. In summary, the nNOS gene is critically involved in the regulation of neurobehavioral effects of alcohol.
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24
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Pulvirenti L, Diana M. Drug dependence as a disorder of neural plasticity: focus on dopamine and glutamate. Rev Neurosci 2001; 12:141-58. [PMID: 11392455 DOI: 10.1515/revneuro.2001.12.2.141] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Drug addiction, as a disease, has grown to reach the level of a social illness. Psychostimulants, opiates, alcohol, nicotine and cannabis abuse affects millions worldwide and virtually all classes of modern society. In spite of the enormous proportions of its spread, intimate neurobiological mechanisms leading to distintictive features of this pathological status, such as craving for the abused substance and loss of control over intake, remain largely obscure and pharmacotherapies sadly unsatisfactory. In the last decade, preclinical and clinical research in this field has made great progress to improve our understanding of the brain mechanisms which form the basis of this illness. The review of recent literature, which represents the focus of the present paper, leads to the emerging consensus that an alteration of physiological mechanisms of neural plasticity within the brain dopamine and glutamate systems may underlie some of the behavioral abnormalities occurring during the dependence cycle. In particular, a reduction of dopamine neuronal activity and glutamate neurotransmission at the level of the ventrotegmental area, after withdrawal from chronic administration of drugs of abuse, may work in concert with alterations in other forebrain areas, such as the nucleus accumbens and the amygdaloid complex. In addition, following prolonged periods of abstinence, even after somatic withdrawal signs have vanished, responsiveness of these systems to drugs of abuse remains abnormal. This suggests that these two neurotransmitters may play a substantial role in the long-lasting, enduring changes typical of the addictive process and may represent ideal targets for pharmacological intervention aimed at normalizing forms of neural plasticity impaired after chronic drug intake.
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Affiliation(s)
- L Pulvirenti
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California, USA
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25
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Naassila M, Beaugé FJ, Sébire N, Daoust M. Intracerebroventricular injection of antisense oligos to nNOS decreases rat ethanol intake. Pharmacol Biochem Behav 2000; 67:629-36. [PMID: 11164095 DOI: 10.1016/s0091-3057(00)00407-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nitric oxide (NO) has been implicated in alcohol drinking behavior using NO synthase (NOS) inhibitors that are nonselective of the different isoforms of NOS. In the brain, there are two constitutive isoforms of NOS, neuronal NOS (nNOS) and endothelial NOS (eNOS). We used an antisense oligodeoxynucleotide directed against nNOS in ethanol dependent male Wistar rats to examine the specific contribution of nNOS in the control of ethanol intake. Rats were subjected to a free-choice situation water/ethanol (10% v/v) after chronic ethanol intoxication by inhalation of ethanol vapor. During the free-choice situation, rats were twice daily for 4 days intracerebroventricularly injected with either saline, or end-capped phosphorothioate-protected antisense or mismatch oligodeoxynucleotide (25 microg/4 microl per injection), or acamprosate (1 mg/kg body weight) as reference product for its anticraving properties. Our results showed that the antisense treatment, but not the mismatch treatment, reduced both ethanol intake and ethanol preference during treatment and posttreatment periods (by 25-30%) without alteration of the body weight gain. The antisense treatment, but not the mismatch treatment, also down-regulated nNOS mRNA levels (by 30%) and NOS activity in the hippocampus. The anticraving drug, acamprosate reduced both ethanol intake (by 58%) and ethanol preference. All these results suggest that nNOS is involved in the regulation of alcohol dependence.
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Affiliation(s)
- M Naassila
- Laboratoire de Physiologie et Unité de Recherches sur les Adaptations Physiologiques et Comportementales, Faculté de Pharmacie, Université de Picardie Jules Verne, 1 rue des Louvels, 80000, Amiens, France.
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26
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Itzhak Y, Martin JL. Blockade of alcohol-induced locomotor sensitization and conditioned place preference in DBA mice by 7-nitroindazole. Brain Res 2000; 858:402-7. [PMID: 10708693 DOI: 10.1016/s0006-8993(00)01940-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Our previous studies indicated that inhibition or ablation of the neuronal nitric oxide synthase (nNOS) prevents the development of sensitization to the locomotor-stimulating effect of cocaine and cocaine-induced conditioned place preference (CPP). The present study was undertaken to investigate the effect of the nNOS inhibitor, 7-nitroindazole (7-NI), on ethanol-induced locomotor sensitization and CPP in DBA/2J mice. Administration of ethanol (1.5 g/kg; i.p.) for 7 days resulted in a progressive increase in the locomotor-stimulating effect of ethanol. Pretreatment with 7-NI (25 mg/kg) blocked the expression of the sensitized response to ethanol. A challenge injection of ethanol given 1 week and then 4 weeks following withdrawal from ethanol indicated that (a) ethanol sensitization was long lasting, and (b) the co-administration of 7-NI and ethanol attenuated the sensitized response to ethanol challenge. The CPP experiments showed that pairing four ethanol (2.5 g/kg) injections with a specific environment resulted in a marked preference for the drug-paired environment. The pretreatment with 7-NI (25 mg/kg) completely blocked ethanol-induced CPP. 7-NI alone produced neither rewarding nor aversive effects. Taken together, results of the present study indicate that blockade of nNOS by 7-NI-attenuated ethanol-induced behavioral sensitization and completely blocked the rewarding effect of ethanol. These findings support the role of NO in ethanol actions and further suggest that the nNOS system is relevant to the rewarding effects of various drugs of abuse.
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Affiliation(s)
- Y Itzhak
- Department of Psychiatry and Behavioral Science (R-629), Room 503, Gautier Building, University of Miami School of Medicine, Miami, FL 33101, USA.
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27
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Koros E, Kostowski W, Bienkowski P. Discriminative stimulus properties of ethanol in rats: studies on the role of nitric oxide. Pharmacol Biochem Behav 1999; 62:607-12. [PMID: 10208365 DOI: 10.1016/s0091-3057(98)00201-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The present study examined the role of the L-arginine-nitric oxide pathway in mediation of the ethanol interoceptive (discriminative) cue. Adult male Wistar rats (n = 16) were trained to discriminate ethanol (1 g/kg, 10% v/v) from saline under a fixed-ratio 10 (FR10) schedule of sweetened milk reinforcement. A nonselective nitric oxide synthase (NOS) inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME; 10-540 mg/kg) did not substitute for ethanol. Similarly, a relatively selective neuronal NOS inhibitor, 7-nitroindazole (7-NI; 10-80 mg/kg), did not mimic the ethanol cue. However, both L-NAME and 7-NI produced significant reduction in the rate of operant responding. A nitric oxide precursor, L-arginine (100-500 mg/kg) neither substituted for nor antagonize the ethanol stimulus. Taken together, these results suggest that the L-arginine-nitric oxide pathway is not involved in mediation of the discriminative stimulus effects of ethanol in the rat.
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Affiliation(s)
- E Koros
- Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, Warsaw, Poland
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28
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Kostowski W, Bieńkowski P. Discriminative stimulus effects of ethanol: neuropharmacological characterization. Alcohol 1999; 17:63-80. [PMID: 9895039 DOI: 10.1016/s0741-8329(98)00035-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Generally, compounds discriminated by animals possess psychotropic effects in animals and humans. As with many other drugs of abuse, strength of the ethanol discriminative stimulus is dose related. The majority of studies show that doses close to 1.0 g/kg are close to the minimum at which the discrimination can be learned easily. Substitution studies suggest that anxiolytic, sedative, atactic, and myorelaxant effects of ethanol all play an important role in the formation of its intercoeptive stimulus. Low doses of ethanol produce more excitatory cues, similar to amphetamine-like subjective stimuli, whereas higher doses produce rather sedative/hypnotic stimuli similar to those elicited by barbiturates. Substitution studies have shown that the complete substitution for ethanol may be exerted by certain GABA-mimetic drugs acting through different sites within the GABA(A)-benzodiazepine receptor complex (e.g., diazepam, pentobarbital, certain neurosteroids), gamma-hydroxybutyrate, and antagonists of the glutamate NMDA receptor. Among the NMDA receptor antagonists both noncompetitive (e.g., dizocilpine) and competitive antagonists (e.g., CGP 40116) are capable of substituting for ethanol. Further, some antagonists of strychnine-insensitive glycine modulatory sites among the NMDA receptor complex (e.g., L-701,324) dose-dependently substitute for the ethanol discriminative stimulus. On the other hand, neither GABA-benzodiazepine antagonists nor NMDA receptor agonists produce contradictory effects (i.e., reduce the ethanol discriminative stimulus). There is influence of a particular training dose of ethanol on the substitution pattern of different compounds. For example, 5-HT(1B/2C) agonists substitute for intermediate (1.0 g/kg) but not higher (2.0 g/kg) ethanol training doses. Discrimination studies with ethanol and drugs acting on NMDA and GABA receptors consistently indicate asymmetrical generalization. For example, ethanol is able to generalize to barbiturates and benzodiazepines, but neither the benzodiazepine nor barbiturate response generalizes to ethanol. Only a few drugs are able to antagonize, at least to some extent, the discriminative stimulus of ethanol (e.g., partial inverse GABA-benzodiazepine receptor antagonist Ro 15-4513 and the opioid antagonist naloxone). The ethanol stimulus effect may be increased (i.e., stronger recognition) by N-cholinergic drugs (nicotine), dopaminergic drugs (apomorphine), and 5-HT3 receptor agonists (m-chlorophenylbiguanide). Thus, the ethanol stimulus is composed of the several components, with the NMDA receptor and GABA(A) receptor complex being of particular importance. This suggests that a drug mixture may be more capable of substituting for ethanol (or block its stimulus) than a single compound. The ability of drugs to substitute for the ethanol discriminative stimulus is frequently, although not preclusively, associated with the reduction of voluntary ethanol consumption. The examples of positive correlation are gamma-hydroxybutyrate, possibly memantine and certain serotonergic drugs such as fluoxetine. However, it remains uncertain to what extent the discriminative stimulus of ethanol can be seen as relevant in the understanding of the complex mechanisms of dependence.
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Affiliation(s)
- W Kostowski
- Department of Pharmacology & Physiology of the Nervous System, Institute of Psychiatry & Neurology, Warsaw, Poland
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29
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Castaneda R, Sussman N, Levy R, O'Malley M, Westreich L. A review of the effects of moderate alcohol intake on psychiatric and sleep disorders. RECENT DEVELOPMENTS IN ALCOHOLISM : AN OFFICIAL PUBLICATION OF THE AMERICAN MEDICAL SOCIETY ON ALCOHOLISM, THE RESEARCH SOCIETY ON ALCOHOLISM, AND THE NATIONAL COUNCIL ON ALCOHOLISM 1998; 14:197-226. [PMID: 9751947 DOI: 10.1007/0-306-47148-5_9] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In this chapter we discuss the effects of moderate ethanol consumption on the treatment of psychiatric and sleep disorders. A review of the literature on the interactions of ethanol with neurotransmitters and psychotropic medications suggests that although ethanol affects the clinical course of psychiatric and sleep disorders by different mechanisms, it does so principally through perturbations it causes in the balance of central nervous system neurotransmitter systems, which may modify the clinical course of primary psychiatric and sleep disorders and undermine the therapeutic response to psychotropic medications. Neurotransmitter responses may also be manifested clinically by rebound phenomena, akin to a subsyndromal withdrawal, which affect sleep and precipitate anxiety and mood symptoms. In addition, ethanol also modifies the clearance and disposition of a variety of psychotropic metabolites and interferes with their clinical effectiveness. We recommend that most psychiatric patients, and all patients with sleep disorders, should abstain from even moderate ethanol use, as this may adversely affect their clinical course and response to treatment.
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Affiliation(s)
- R Castaneda
- Department of Psychiatry, New York University School of Medicine, Bellevue Hospital Medical Center, New York 10016, USA
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30
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Abstract
The L-arginine-nitric oxide pathway is important to both physiological and pathologic brain events. Brain tissue contains cells able to express all known isoforms of nitric oxide synthase, the rate-limiting enzyme in nitric oxide (NO) production and release. Effects of ethanol on NO production may be important to ethanol modification of brain function. Recent studies support this idea and demonstrate diverse interactions. For example, acute ethanol treatment decreases NMDA- and cytokine-stimulated NO synthesis by cortical neurons and glia, respectively, but enhances cytokine-stimulated NO synthesis in blood-brain barrier endothelial cells and does not affect norepinephrine-stimulated NO synthesis in medial basal hypothalamus. Furthermore, chronic ethanol enhances NMDA-stimulated NO synthesis in cortical neurons, but more potently decreases cytokine-induced NO synthesis in glial cells. The mechanisms underlying these effects are partially understood and include changes in NOS-2 gene expression. These observations illustrate that ethanol selectively affects NO production by brain cells, which may relate to reported behavioral interactions, but the extend and direction of change depends on cell type and length of exposure.
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Affiliation(s)
- P J Syapin
- Department of Pharmacology, Texas Tech University Health Sciences Center, Lubbock 79430-0001, USA
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31
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Abstract
Nitric oxide is an important messenger in the central nervous system and several types of evidence suggest that it mediates various alcohol effects. Treatment with a nitric oxide synthase inhibitor enhances the acute central depressant or anesthetic effect of alcohol and decreases some stimulatory effects of alcohol withdrawal after chronic alcohol treatment. Conversely, treatment with a nitric oxide donor inhibits the anesthetic effect of alcohol, blocks the effect of the nitric oxide synthase inhibitor on alcohol anesthesia, and enhances the severity of some alcohol withdrawal signs. These results indicate that changes in nitric oxide synthesis mediate some aspects of alcohol intoxication and withdrawal and that nitric oxide systems represent an important therapeutic target for the development of agents to treat alcoholism and alcohol intoxication.
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Affiliation(s)
- M L Adams
- Washington University School of Medicine, St. Louis, MO 63110-1093, USA.
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