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Wen RT, Liang JH, Zhang HT. Targeting Phosphodiesterases in Pharmacotherapy for Substance Dependence. ADVANCES IN NEUROBIOLOGY 2018; 17:413-444. [PMID: 28956341 DOI: 10.1007/978-3-319-58811-7_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Substance dependence is a chronic relapsing brain disorder associated with adaptational changes in synaptic plasticity and neuronal functions. The high levels of substance consumption and relapse rate suggest more reliable medications are in need to better address the underlying causes of this disease. It has been well established that the intracellular second messengers cyclic AMP (cAMP) and cyclic GMP (cGMP) and their signaling systems play an important role in the molecular mechanisms of substance taking behaviors. On this basis, the phosphodiesterase (PDE) superfamily, which crucially controls cyclic nucleotide levels by catalyzing their hydrolysis, has been proposed as a novel class of therapeutic targets for substance use disorders. This chapter reviews the expression patterns of PDEs in the brain with regard to neural structures underlying the dependent process and highlights available evidence for a modulatory role of PDEs in substance dependence.
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Affiliation(s)
- Rui-Ting Wen
- Department of Pharmacy, Peking University People's Hospital, Beijing, 100044, China
| | - Jian-Hui Liang
- Department of Molecular and Cellular Pharmacology, Peking University School of Pharmaceutical Sciences, Beijing, 100191, China.
| | - Han-Ting Zhang
- Department of Behavioral Medicine and Psychiatry, West Virginia University Health Sciences Center, 1 Medical Center Drive, Morgantown, WV, 26506, USA. .,Department of Physiology and Pharmacology, West Virginia University Health Sciences Center, 1 Medical Center Drive, Morgantown, WV, 26506, USA. .,Institute of Pharmacology, Taishan Medical University, Taian, 271016, China.
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Seyedi SY, Salehi F, Payandemehr B, Hossein S, Hosseini-Zare MS, Nassireslami E, Yazdi BB, Sharifzadeh M. Dual effect of cAMP agonist on ameliorative function of PKA inhibitor in morphine-dependent mice. Fundam Clin Pharmacol 2013; 28:445-54. [PMID: 24033391 DOI: 10.1111/fcp.12045] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/24/2013] [Accepted: 07/08/2013] [Indexed: 12/15/2022]
Abstract
The present study shows interactive effects of bucladesine (db-cAMP) as a cyclic adenosine monophosphate (cAMP) agonist and H-89 as a protein kinase A (PKA) inhibitor on naloxone-induced withdrawal signs in morphine-dependent mice. Animals were treated subcutaneously with morphine thrice daily with doses progressively increased from 50 to 125 mg/kg. A last dose of morphine (50 mg/kg) was administered on the 4th day. Several withdrawal signs were precipitated by intraperitoneal (i.p.) administration of naloxone (5 mg/kg). Different doses of bucladesine (50, 100, 200 nm/mouse) and H-89 (0.05, 0.5, 1, 5 mg/kg) were administered (i.p.) 60 min before naloxone injection. In combination groups, bucladesine was injected 15 min before H-89 injection. Single administration of H-89 (0.5, 1, 5 mg/kg) and bucladesine (50, 100 nm/mouse) significantly attenuated prominent behavioral signs of morphine withdrawal. Lower doses of bucladesine (50, 100 nm/mouse) in combination with H-89 (0.05 mg/kg) increased the inhibitory effects of H-89 on withdrawal signs while in high dose (200 nm/mouse) decreased the ameliorative function of H-89 (0.05 mg/kg) in morphine-dependent animals. It is concluded that H-89 and bucladesine could affect morphine withdrawal syndrome via possible interaction with cyclic nucleotide messengering systems, protein kinase A signaling pathways, and modified related neurotransmitters.
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Affiliation(s)
- Seyedeh Y Seyedi
- Department of Pharmacology and Toxicology, Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, PO Box 14155-6451, Tehran, Iran
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Fliegel S, Brand I, Spanagel R, Noori HR. Ethanol-induced alterations of amino acids measured by in vivo microdialysis in rats: a meta-analysis. In Silico Pharmacol 2013; 1:7. [PMID: 25505652 PMCID: PMC4230485 DOI: 10.1186/2193-9616-1-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/07/2013] [Indexed: 12/14/2022] Open
Abstract
PURPOSE In recent years in vivo microdialysis has become an important method in research studies investigating the alterations of neurotransmitters in the extracellular fluid of the brain. Based on the major involvement of glutamate and γ-aminobutyric acid (GABA) in mediating a variety of alcohol effects in the mammalian brain, numerous microdialysis studies have focused on the dynamical behavior of these systems in response to alcohol. METHODS Here we performed multiple meta-analyses on published datasets from the rat brain: (i) we studied basal extracellular concentrations of glutamate and GABA in brain regions that belong to a neurocircuitry involved in neuropsychiatric diseases, especially in alcoholism (Noori et al., Addict Biol 17:827-864, 2012); (ii) we examined the effect of acute ethanol administration on glutamate and GABA levels within this network and (iii) we studied alcohol withdrawal-induced alterations in glutamate and GABA levels within this neurocircuitry. RESULTS For extraction of basal concentrations of these neurotransmitters, datasets of 6932 rats were analyzed and the absolute basal glutamate and GABA levels were estimated for 18 different brain sites. In response to different doses of acute ethanol administration, datasets of 529 rats were analyzed and a non-linear dose response (glutamate and GABA release) relationship was observed in several brain sites. Specifically, glutamate in the nucleus accumbens shows a decreasing logarithmic dose response curve. Finally, regression analysis of 11 published reports employing brain microdialysis experiments in 104 alcohol-dependent rats reveals very consistent augmented extracellular glutamate and GABA levels in various brain sites that correlate with the intensity of the withdrawal response were identified. CONCLUSIONS In summary, our results provide standardized basal values for future experimental and in silico studies on neurotransmitter release in the rat brain and may be helpful to understand the effect of ethanol on neurotransmitter release. Furthermore, this study illustrates the benefit of meta-analyses using the generalization of a wide range of preclinical data.
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Affiliation(s)
- Sarah Fliegel
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
| | - Ines Brand
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
| | - Hamid R Noori
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
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Javadi S, Ejtemaeimehr S, Keyvanfar HR, Moghaddas P, Aminian A, Rajabzadeh A, Mani AR, Dehpour AR. Pioglitazone potentiates development of morphine-dependence in mice: possible role of NO/cGMP pathway. Brain Res 2013; 1510:22-37. [PMID: 23399681 DOI: 10.1016/j.brainres.2012.12.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/15/2012] [Accepted: 12/13/2012] [Indexed: 01/23/2023]
Abstract
Peroxizome proliferator-activated receptor gamma (PPARγ) is highly expressed in the central nervous system where it modulates numerous gene transcriptions. Nitric oxide synthase (NOS) expression could be modified by simulation of PPARγ which in turn activates nitric oxide (NO)/soluble guanylyl-cyclase (sGC)/cyclic guanosine mono phosphate (cGMP) pathway. It is well known that NO/cGMP pathway possesses pivotal role in the development of opioid dependence and this study is aimed to investigate the effect of PPARγ stimulation on opioid dependence in mice as well as human glioblastoma cell line. Pioglitazone potentiated naloxone-induced withdrawal syndrome in morphine dependent mice in vivo. While selective inhibition of PPARγ, neuronal NOS or GC could reverse the pioglitazone-induced potentiation of morphine withdrawal signs; sildenafil, a phosphodiesterase-5 inhibitor amplified its effect. We also showed that nitrite levels in the hippocampus were significantly elevated in pioglitazone-treated morphine dependent mice. In the human glioblastoma (U87) cell line, rendered dependent to morphine, cAMP levels did not show any alteration after chronic pioglitazone administration while cGMP measurement revealed a significant rise. We were unable to show a significant alteration in neuronal NOS mRNA expressions by pioglitazone in mice hippocampus or U87 cells. Our results suggest that pioglitazone has the ability to enhance morphine-dependence and to augment morphine withdrawal signs. The possible pathway underlying this effect is through activation of NO/GC/cGMP pathway.
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Affiliation(s)
- Shiva Javadi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box 13145-784, Tehran, Iran
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Yan HT, Wu N, Lu XQ, Su RB, Zheng JQ, Li J. Aquaporin-4 deficiency attenuates opioid dependence through suppressing glutamate transporter-1 down-regulation and maintaining glutamate homeostasis. CNS Neurosci Ther 2012; 19:12-9. [PMID: 23051665 DOI: 10.1111/cns.12012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 08/20/2012] [Accepted: 08/26/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Glutamate homeostasis plays a critical role in mediating the addiction-related behaviors. Therefore, preventing the disruption or reestablishing of it is a novel strategy for the treatment of addiction. Glutamate transporters are responsible for clearing extracellular glutamate and maintaining glutamate homeostasis. Our previous work demonstrated that aquaporin-4 (AQP4) deficiency attenuated morphine dependence, but the mechanisms are unclear. According to the recent evidence that AQP4 might form a functional complex with glutamate transporter-1 (GLT-1), this study focused on whether AQP4 participates in the modulation of GLT-1 and glutamate homeostasis in morphine-dependent mice. RESULTS We found that AQP4 knockout prevented the down-regulations of GLT-1 expression and glutamate clearance when mice were repeatedly treated with morphine. Further study revealed that inhibition of GLT-1 by dihydrokainic acid (DHK) initiated morphine dependence in AQP4 knockout mice. In addition, AQP4 knockout abolished both decreases and increases in the extracellular glutamate levels in the prefrontal cortex during repeated morphine treatment and naloxone-precipitated withdrawal. CONCLUSION AQP4 deficiency suppresses the down-regulation of GLT-1, and the disruption of glutamate homeostasis caused by repeated exposure to morphine, pointing to a strategy for maintaining glutamate homeostasis and thereby treating addiction through the modulation of AQP4 function and expression.
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Affiliation(s)
- Hai-Tao Yan
- Beijing Institute of Pharmacology and Toxicology, Beijing, China
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Núñez C, González-Cuello A, Sánchez L, Vargas ML, Milanés MV, Laorden ML. Effects of rolipram and diazepam on the adaptive changes induced by morphine withdrawal in the hypothalamic paraventricular nucleus. Eur J Pharmacol 2009; 620:1-8. [PMID: 19683523 DOI: 10.1016/j.ejphar.2009.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 07/14/2009] [Accepted: 08/03/2009] [Indexed: 01/23/2023]
Abstract
A role for the cyclic AMP systems in the development of morphine dependence has been previously reported. In this study we investigated whether morphine dependence was inhibited by phosphodiesterase (PDE) 4 inhibitors rolipram and diazepam. Dependence on morphine was induced by a 7-day s.c. implantation of morphine pellets. On day 8, morphine withdrawal was precipitated by an injection of naloxone. In order to determine the effect of rolipram and diazepam rats were injected with these drugs once daily for seven days as well as 30 min before of naloxone injection. When opioid withdrawal was precipitated, an enhanced noradrenaline turnover and increased level of cyclic AMP and cyclic GMP in the hypothalamic paraventricular nucleus (PVN) were observed 30 min after naloxone administration. Moreover, c-Fos expression was induced in the PVN after naloxone-precipitated morphine withdrawal. Co-administration of rolipram or diazepam with morphine during the pre-treatment period, significantly reduced the signs of withdrawal, the enhancement of noradrenaline turnover and the increase in cyclic AMP. However, these inhibitors did not modify either levels of cyclic GMP or c-Fos expression in the PVN. These findings demonstrate that co-administration of rolipram or diazepam with morphine attenuate the withdrawal syndrome and suggest that these compounds may prevent the up-regulation of the cyclic AMP pathway and the associated increase in cyclic AMP level in morphine-withdrawn rats.
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Affiliation(s)
- Cristina Núñez
- Department of Pharmacology, Faculty of Medicine, University of Murcia, Spain
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Shijun H, Liping Z, Yongqiang Q, Zhen L, Yonghe Z, Lihua L. Morphine-induced changes of adenylate and guanylate cyclase in locus ceruleus, periaqueductal gray, and substantia nigra in rats. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2009; 35:133-7. [PMID: 19353384 DOI: 10.1080/00952990902825389] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVES To observe the changes of adenylate cyclase (AC) and guanylate cyclase (GC) in the cerebral regions including the locus ceruleus, periaqueductal gray, and substantia nigra in rats that were physiologically dependent on morphine. We also investigated the relationship of enzymatic changes in these cerebral regions to the mechanism of morphine dependence. METHODS A morphine-dependent rat model was established and withdrawal symptoms evaluated. Enzyme histochemistry was used to detect the variations of AC and GC in cerebral regions. RESULTS Compared to controls, AC and GC significantly increased in morphine-dependent groups. Comparisons of four different morphine-dependent groups also showed AC and GC significantly differed at weeks 1, 2, 4, and 8. CONCLUSIONS Results found that the content of AC and GC increased in these cerebral regions in rats that demonstrated morphine dependence and appeared to be closely linked to increases in AC and GC activity.
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Affiliation(s)
- Hong Shijun
- The School of Forensic Medicine, Kunming University of Medical Sciences, Kunming City, Yunnan Province, People's Republic of China
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Addictive evaluation of cholic acid-verticinone ester, a potential cough therapeutic agent with agonist action of opioid receptor. Acta Pharmacol Sin 2009; 30:559-66. [PMID: 19417735 DOI: 10.1038/aps.2009.43] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
AIM The purpose of this work was to search for potential drugs with potent antitussive and expectorant activities as well as a low toxicity, but without addictive properties. Cholic acid-verticinone ester (CA-Ver) was synthesized based on the clearly elucidated antitussive and expectorant activities of verticinone in bulbs of Fritillaria and different bile acids in Snake Bile. In our previous study, CA-Ver showed a much more potent activity than codeine phosphate. This study was carried out to investigate the central antitussive mechanism and the addictive evaluation of CA-Ver. METHODS Testing on a capsaicin-induced cough model of mice pretreated with naloxone, a non-selective opioid receptor antagonist, was performed for the observation of CA-Ver's central antitussive mechanism. We then took naloxone-induced withdrawal tests of mice for the judgment of CA-Ver's addiction. Lastly, we determined the opioid dependence of CA-Ver in the guinea pig ileum. RESULTS The test on the capsaicin-induced cough model showed that naloxone could block the antitussive effect of CA-Ver, suggesting the antitussive mechanism of CA-Ver was related to the central opioid receptors. The naloxone-urged withdrawal tests of the mice showed that CA-Ver was not addictive, and the test of the opioid dependence in the guinea pig ileum showed that CA-Ver had no withdrawal response. CONCLUSION These findings suggested that CA-Ver deserved attention for its potent antitussive effects related to the central opioid receptors, but without addiction, and had a good development perspective.
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González-Cuello A, Sánchez L, Hernández J, Teresa Castells M, Victoria Milanés M, Laorden ML. Phosphodiesterase 4 inhibitors, rolipram and diazepam block the adaptive changes observed during morphine withdrawal in the heart. Eur J Pharmacol 2007; 570:1-9. [PMID: 17601555 DOI: 10.1016/j.ejphar.2007.05.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 05/08/2007] [Accepted: 05/15/2007] [Indexed: 11/21/2022]
Abstract
In this study, we investigated whether morphine dependence was inhibited by phosphodiesterase (PDE) 4 inhibitors rolipram and diazepam, since a role for the cyclic AMP systems in the development of morphine dependence was reported. Dependence of morphine was induced by a 7-day s.c. implantation of morphine pellets. Morphine withdrawal was precipitated on day 8 by an injection of naloxone. In order to determine the effect of rolipram or diazepam the animals were injected with these drugs for seven days and 30 min before the administration of naloxone. When opioid withdrawal was precipitated, enhancement of noradrenaline (NA) turnover in the heart was observed 30 min after naloxone administration. Moreover, morphine withdrawal induces Fos expression, increase in cyclic AMP and cyclic GMP levels. Co-administration of rolipram or diazepam with morphine during the pre-treatment period significantly reduces the signs of withdrawal symptoms, the enhancement of NA turnover, the increase in cyclic AMP and the Fos expression. However, these inhibitors did not modify the levels of cyclic GMP. These findings demonstrated that co-administration of rolipram or diazepam with morphine abolish the development of morphine dependence and suggest that these compounds prevent the up-regulation of the cyclic AMP pathway and the associated increase in cyclic AMP level after naloxone administration.
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Affiliation(s)
- Ana González-Cuello
- Department of Pharmacology, University School of Medicine, 30100 Murcia, Spain
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Dong Z, Mao R, Han H, Cao J, Xu L. Morphine withdrawal modifies antinociceptive effects of acute morphine in rats. Biochem Biophys Res Commun 2006; 346:578-82. [PMID: 16762316 DOI: 10.1016/j.bbrc.2006.05.151] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Accepted: 05/13/2006] [Indexed: 10/24/2022]
Abstract
Repeated opioid use is known to cause tolerance of antinociceptive effects. Whether opioid abstinence modifies antinociceptive effects is unknown. Here we reported that morphine withdrawal for 18 h and 4 days after repeated morphine treatment largely reduced tail-flick latencies compared with control, while the rats showed severe withdrawal syndromes. However, the latencies and withdrawal syndromes were restored to control level at 20 days withdrawal. Similarly, antinociceptive effects of acute morphine were decreased at 18 h and further decreased at 4 days but restored to control level at 20 days withdrawal. Behavioral stress that was given to the rats at 18 h withdrawal further reduced tail-flick latencies and antinociceptive effects. Conversely, the glucocorticoid receptor antagonist RU38486 increased tail-flick latencies and antinociceptive effects at 4 days withdrawal. These results suggest that morphine withdrawal could evoke behavioral stress to modify antinociceptive effects, implicating a significant influence of opioid abstinence on chronic pain treatment.
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Affiliation(s)
- Zhifang Dong
- Key Laboratory of Animal Models and Human Disease Mechanisms, and Laboratory of Learning and Memory, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, PR China
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Liang DY, Clark JD. Modulation of the NO/CO-cGMP signaling cascade during chronic morphine exposure in mice. Neurosci Lett 2004; 365:73-7. [PMID: 15234476 DOI: 10.1016/j.neulet.2004.04.054] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Revised: 04/21/2004] [Accepted: 04/23/2004] [Indexed: 11/20/2022]
Abstract
The chronic administration of morphine and related opioid drugs results in tolerance and dependence which reduces the clinical utility of these agents. The CO/NO-cGMP signal transduction cascade plays an important role in morphine tolerance. Principal components of this pathway include heme oxygenase (HO), nitric oxide synthase (NOS), soluble guanylate cyclase (sGC) and cyclic GMP-dependent protein kinase (cGK). We measured and compared the spinal gene expression patterns of these key components using real-time PCR and Western blot analysis after chronic morphine treatment in mice. Our findings indicate that the CO/NO-cGMP signaling pathway is upregulated at multiple points after morphine exposure demonstrating a coordinated molecular and biochemical response. These findings underscore the importance of this signaling pathway in the neuroplastic events occurring during chronic opioid exposure and the value of analyzing the participation of multiple components of a signaling pathway simultaneously rather than individual members in isolation.
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Affiliation(s)
- De-Yong Liang
- Department of Anesthesiology, Stanford University and Veterans Affairs Palo Alto Health Care System, 112A, 3801 Miranda Avenue, Palo Alto, CA 94304, USA.
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Bull PM, Ludwig M, Blackburn-Munro GJ, Delgado-Cohen H, Brown CH, Russell JA. The role of nitric oxide in morphine dependence and withdrawal excitation of rat oxytocin neurons. Eur J Neurosci 2004; 18:2545-51. [PMID: 14622155 DOI: 10.1046/j.1460-9568.2003.03005.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Magnocellular oxytocin neurons develop morphine dependence after intracerebroventricular infusion for 5 days as revealed by their profound excitation following naloxone-induced withdrawal. Oxytocin neurons strongly express nitric oxide synthase (NOS) and nitric oxide (NO) inhibits their activity. This study investigated whether excitation of oxytocin neurons during morphine withdrawal involves reduced activity of NOS and NO. Neuron activity was measured in urethane-anaesthetized rats with blood sampling for oxytocin radioimmunoassay and extracellular single unit firing rate recording of supraoptic nucleus oxytocin neurons. To compare morphine-dependent and -naive rats oxytocin secretion was measured during stimulation by intravenous hypertonic saline infusion. Prior treatment with Nomega-nitro-l-arginine methyl ester, a NOS inhibitor, facilitated osmotically stimulated oxytocin secretion in both morphine-dependent and -naive rats. The facilitation was not different between these groups when corrected for the slower responses observed in morphine-dependent rats. Treatment of morphine-dependent rats with Nomega-nitro-l-arginine methyl ester also enhanced oxytocin secretion during naloxone-precipitated withdrawal. Oxytocin neurons excited by withdrawal were recorded during microdialysis application to the supraoptic nucleus of the NO donor sodium nitroprusside alone and in combination with the GABAA antagonist bicuculline. Sodium nitroprusside inhibited oxytocin neurons during naloxone-precipitated morphine withdrawal and, while bicuculline alone increased firing rate, it did not reduce the inhibition by sodium nitroprusside, in contrast with previous findings in naive rats. Together, these findings indicate that NO restraint of oxytocin secretion is not curtailed during morphine dependence and remains a potent inhibitor of withdrawal excitation despite reduced effectiveness on GABA innervation of the supraoptic nucleus. Hence there is no evidence that changes in NO regulation underlie excitation of oxytocin neurons during opiate withdrawal in morphine dependence.
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Affiliation(s)
- Philip M Bull
- School of Biomedical and Clinical Laboratory Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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Batista A, Macedo T, Tavares P, Ribeiro CF, Relvas J, Gomes P, Ramalheira C, Botto I, Vale L, Ferreira L, Guete O, Ruiz G. Nitric oxide production and nitric oxide synthase expression in platelets from heroin abusers before and after ultrarapid detoxification. Ann N Y Acad Sci 2002; 965:479-86. [PMID: 12105123 DOI: 10.1111/j.1749-6632.2002.tb04189.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Prolonged heroin abuse has been associated with neurotoxicity. Thus, the involvement of nitric oxide (NO) in heroin-induced dopaminergic neurotoxicity could be a reasonable explanation for heroin-induced changes in brain. Enzymatically derived NO has been implicated in numerous physiological and pathological processes in the brain. Whereas during development NO participates in growing and maturation processes, excess NO production in the adult in response to inflammation, injury, or trauma, participates in both cell death and repair. The expression and activity of the inducible isoform of NO synthase (iNOS) play a pivotal role in sustained and elevated NO release. Recent evidence suggests that neurons can respond to proinflammatory stimuli and take part in brain inflammation. The effect of heroin abuse on platelet NO production and on expression of iNOS in drug addicts submitted to an ultrarapid detoxification was studied. The NO production was estimated from the nitrite concentration, and nitric oxide synthase was determined by Western blotting analysis. Results showed no difference in nitrite content of resting platelets between heroin abuser and control groups. However, after platelet stimulation, heroin abusers showed significantly lower nitrite values. The Western blotting analysis reinforced these results. After ultrarapid detoxification, platelet nitrite production in heroin abusers showed no differences compared to control subjects. Our results suggest that heroin consumption decreases the iNOS synthase expression and platelet NO production. Detoxification treatment restores these changes.
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Affiliation(s)
- Ana Batista
- Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
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