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The Effects of the Inhalant Toluene on Cognitive Function and Behavioral Flexibility: A Review of Recent Findings. ADDICTION NEUROSCIENCE 2023; 5:100059. [PMID: 36798693 PMCID: PMC9928149 DOI: 10.1016/j.addicn.2022.100059] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Substance use disorder (SUD) is characterized, in part, by lack of control over drug seeking and taking. The prefrontal cortex (PFC) is highly involved in control of behavior and deficits in PFC structure and function have been demonstrated in clinical and preclinical studies of SUD. Of the various classes of drugs associated with the development of SUD, inhalants are among the least studied despite their widespread use among adolescents and children. In this work, we review what is currently known regarding the sites and mechanisms of action of inhalants with a focus on the volatile solvent toluene that is contained in a wide variety of legal and easily obtained products. We then describe how inhalants including toluene affect various behaviors with an emphasis on those associated with PFC function and how chronic use of inhalants alters brain structure and neuronal signaling. Findings from these studies highlight advances made in recent years that have expanded our understanding of the effects of inhalants on brain structure and reinforce the need for continued work in this field.
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2
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Toluene Can Disrupt Rat Ovarian Follicullogenesis and Steroidogenesis and Induce Both Autophagy and Apoptosis. BIOLOGY 2021; 10:biology10111153. [PMID: 34827146 PMCID: PMC8615224 DOI: 10.3390/biology10111153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 11/17/2022]
Abstract
Toluene has been shown to be highly toxic to humans and animals and can cause damage to various tissues. However, studies reporting its effects on ovarian function are still limited. In this study, we investigated the in vivo effect of toluene using female Wistar rats. We found that toluene exposure decreased ovarian weight and affected ovarian structure by increasing the number of abnormally growing follicles. Moreover, it significantly increased progesterone and testosterone levels. We also showed that toluene exposure decreased GDF-9 protein and its encoding gene. In addition, it inhibited the expression of most of the genes involved in granulosa cell proliferation and differentiation, such as Insl3, ccnd2 and actb. The TUNEL assay showed that apoptosis occurred at the middle and high doses only (4000 and 8000 ppm, respectively), whereas no effect was observed at the low dose (2000 ppm). Interestingly, we showed that toluene exposure induced autophagy as LC3 protein and its encoding gene significantly increased for all doses of treatment. These results may suggest that the activation of autophagy at a low dose of exposure was to protect ovarian cells against death by inhibiting apoptosis, whereas its activation at high doses of exposure triggered apoptosis leading to cell death.
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Dick AL, Zhao Q, Crossin R, Baker‐Andresen D, Li X, Edson J, Roeh S, Marshall V, Bredy TW, Lawrence AJ, Duncan JR. Adolescent chronic intermittent toluene inhalation dynamically regulates the transcriptome and neuronal methylome within the rat medial prefrontal cortex. Addict Biol 2021; 26:e12937. [PMID: 32638524 DOI: 10.1111/adb.12937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/25/2020] [Accepted: 06/24/2020] [Indexed: 12/14/2022]
Abstract
Inhalants containing the volatile solvent toluene are misused to induce euphoria or intoxication. Inhalant abuse is most common during adolescence and can result in cognitive impairments during an important maturational period. Despite evidence suggesting that epigenetic modifications may underpin the cognitive effects of inhalants, no studies to date have thoroughly investigated toluene-induced regulation of the transcriptome or discrete epigenetic modifications within the brain. To address this, we investigated effects of adolescent chronic intermittent toluene (CIT) inhalation on gene expression and DNA methylation profiles within the rat medial prefrontal cortex (mPFC), which undergoes maturation throughout adolescence and has been implicated in toluene-induced cognitive deficits. Employing both RNA-seq and genome-wide Methyl CpG Binding Domain (MBD) Ultra-seq analysis, we demonstrate that adolescent CIT inhalation (10 000 ppm for 1 h/day, 3 days/week for 4 weeks) induces both transient and persistent changes to the transcriptome and DNA methylome within the rat mPFC for at least 2 weeks following toluene exposure. We demonstrate for the first time that adolescent CIT exposure results in dynamic regulation of the mPFC transcriptome likely relating to acute inflammatory responses and persistent deficits in synaptic plasticity. These adaptations may contribute to the cognitive deficits associated with chronic toluene exposure and provide novel molecular targets for preventing long-term neurophysiological abnormalities following chronic toluene inhalation.
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Affiliation(s)
- Alec L.W. Dick
- Florey Institute of Neuroscience and Mental Health University of Melbourne Melbourne VIC Australia
- Department of Stress Neurobiology and Neurogenetics Max Planck Institute of Psychiatry Munich Germany
| | - Qiongyi Zhao
- Queensland Brain Institute University of Queensland Brisbane QLD Australia
| | - Rose Crossin
- Florey Institute of Neuroscience and Mental Health University of Melbourne Melbourne VIC Australia
| | | | - Xiang Li
- Queensland Brain Institute University of Queensland Brisbane QLD Australia
| | - Janette Edson
- Queensland Brain Institute University of Queensland Brisbane QLD Australia
| | - Simone Roeh
- Department of Translational Research in Psychiatry Max Planck Institute of Psychiatry Munich Germany
| | - Victoria Marshall
- Queensland Brain Institute University of Queensland Brisbane QLD Australia
| | - Timothy W. Bredy
- Queensland Brain Institute University of Queensland Brisbane QLD Australia
| | - Andrew J. Lawrence
- Florey Institute of Neuroscience and Mental Health University of Melbourne Melbourne VIC Australia
| | - Jhodie R. Duncan
- Florey Institute of Neuroscience and Mental Health University of Melbourne Melbourne VIC Australia
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Lee MY, Lin BF, Chan MH, Chen HH. Increased behavioral and neuronal responses to a hallucinogenic drug after adolescent toluene exposure in mice: Effects of antipsychotic treatment. Toxicology 2020; 445:152602. [PMID: 32980479 DOI: 10.1016/j.tox.2020.152602] [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: 07/24/2020] [Revised: 09/19/2020] [Accepted: 09/22/2020] [Indexed: 01/23/2023]
Abstract
Toluene has been characterized as a non-classical hallucinogen drug through activation of 5-HT2A receptors and antagonism of NMDA receptors. It remains unclear whether psychotic symptoms after long-term and intense toluene exposure are associated with abnormalities in 5-HT2A receptor function. The present study examined whether the responses to a hallucinogenic 5-HT2A receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) were altered in a mouse model of toluene psychosis. Male NMRI mice were subchronically treated with toluene during adolescence. Reciprocal social interaction test and novel object recognition test were conducted to confirm the persistent behavioral deficits in adulthood. Subsequently, DOI-induced head twitch, c-Fos and Egr-2 expression, field potentials in the medial prefrontal cortex (mPFC), and the levels of 5-HT2A, 5-HT1A and mGlu2 receptors in the mPFC were monitored. Toluene exposure during adolescence produced social and memory impairments and enhanced DOI-induced behavioral, molecular and electrophysiological responses, but did not change the levels of 5-HT2A, 5-HT1A or mGlu2 receptors in the mPFC. Moreover, the effects of haloperidol and risperidone on the behavioral deficits and hyper-responsiveness to DOI after adolescent toluene exposure were compared. When administered after adolescent toluene exposure, risperidone could reverse social withdrawal, cognitive impairment and hypersensitivity to DOI, whereas haloperidol was only beneficial for social withdrawal. These findings suggest that increased functionality of 5-HT2A receptors may play a critical role in solvent-induced psychosis and recommend the antipsychotics with more selective 5-HT2A receptor antagonism as the first-line treatment for solvent-induced psychosis.
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Affiliation(s)
- Mei-Yi Lee
- Center for Neuropsychiatric Research, National Health Research Institutes, 35 Keyan Rd. Zhunan, Miaoli, 35053, Taiwan
| | - Bih-Fen Lin
- Department of Laboratory Medicine and Biotechnology School of Medicine, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien, 97004, Taiwan
| | - Ming-Huan Chan
- Institute of Neuroscience, National Chengchi University, NO. 64, Sec. 2, Zhinan Rd., Taipei, 11605, Taiwan; Research Center for Mind, Brain, and Learning, National Chengchi University, NO. 64, Sec. 2, Zhinan Rd., Taipei, 11605, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, 40402, Taiwan.
| | - Hwei-Hsien Chen
- Center for Neuropsychiatric Research, National Health Research Institutes, 35 Keyan Rd. Zhunan, Miaoli, 35053, Taiwan; Institute of Neuroscience, National Chengchi University, NO. 64, Sec. 2, Zhinan Rd., Taipei, 11605, Taiwan; Ph.D. Program in Tissue Engineering and Regenerative Medicine, National Chung Hsing University, No. 145, Xingda Rd., Taichung, 40227, Taiwan.
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Meher RK, Aghoram R, Nair PP. Adrenoleukodystrophy presenting as glue sniffing. BMJ Case Rep 2020; 13:13/3/e233036. [PMID: 32169980 DOI: 10.1136/bcr-2019-233036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Adrenoleukodystrophy classically presents in childhood with bronze skin, spastic tetraparesis, dysphagia, behavioural abnormalities and adrenal insufficiency. However, atypical presentations are known. Here we report an adolescent with adrenoleukodystrophy who first sought medical attention for glue sniffing.
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Affiliation(s)
- Rajesh Kumar Meher
- Neurology, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry, India
| | - Rajeswari Aghoram
- Neurology, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry, India
| | - Pradeep Pankajakshan Nair
- Neurology, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry, India
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Crossin R, Qama A, Andrews ZB, Lawrence AJ, Duncan JR. The effect of adolescent inhalant abuse on energy balance and growth. Pharmacol Res Perspect 2019; 7:e00498. [PMID: 31384470 PMCID: PMC6664821 DOI: 10.1002/prp2.498] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/21/2019] [Accepted: 05/25/2019] [Indexed: 12/20/2022] Open
Abstract
The abuse of volatile solvents such as toluene is a significant public health concern, predominantly affecting adolescents. To date, inhalant abuse research has primarily focused on the central nervous system; however, inhalants also exert effects on other organ systems and processes, including metabolic function and energy balance. Adolescent inhalant abuse is characterized by a negative energy balance phenotype, with the peak period of abuse overlapping with the adolescent growth spurt. There are multiple components within the central and peripheral regulation of energy balance that may be affected by adolescent inhalant abuse, such as impaired metabolic signaling, decreased food intake, altered dietary preferences, disrupted glucose tolerance and insulin release, reduced adiposity and skeletal density, and adrenal hypertrophy. These effects may persist into abstinence and adulthood, and the long-term consequences of inhalant-induced metabolic dysfunction are currently unknown. The signs and symptoms resulting from chronic adolescent inhalant abuse may result in a propensity for the development of adult-onset metabolic disorders such as type 2 diabetes, however, further research investigating the long-term effects of inhalant abuse upon energy balance and metabolism are needed. This review addresses several aspects of the short- and long-term effects of inhalant abuse relating to energy and metabolic processes, including energy balance, intake and expenditure; dietary preferences and glycemic control; and the dysfunction of metabolic homeostasis through altered adipose tissue, bone, and hypothalamic-pituitary-adrenal axis function.
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Affiliation(s)
- Rose Crossin
- Florey Institute of Neuroscience and Mental HealthParkvilleVIC
- Turning Point, Eastern HealthRichmondVIC
- Eastern Health Clinical SchoolMonash UniversityBox HillVIC
| | - Ashleigh Qama
- Florey Institute of Neuroscience and Mental HealthParkvilleVIC
- WHO Collaborating Centre for Viral HepatitisPeter Doherty Institute for Infection and ImmunityMelbourneVIC
| | - Zane B. Andrews
- Monash Biomedicine Discovery InstituteMonash UniversityClaytonVIC
| | - Andrew J. Lawrence
- Florey Institute of Neuroscience and Mental HealthParkvilleVIC
- Florey Department of Neuroscience and Mental HealthUniversity of MelbourneParkvilleVIC
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Mustonen A, Niemelä S, McGrath JJ, Murray GK, Nordström T, Mäki P, Miettunen J, Scott JG. Adolescent inhalant use and psychosis risk - a prospective longitudinal study. Schizophr Res 2018; 201:360-366. [PMID: 29958751 DOI: 10.1016/j.schres.2018.05.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 05/02/2018] [Accepted: 05/12/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Cross-sectional studies have suggested inhalant use is associated with psychosis. This association was examined in a longitudinal study accounting for other substance use and potential confounders. METHODS We used a prospective sample (N = 6542) from the Northern Finland Birth Cohort 1986. Self-report questionnaires on substance use and psychotic experiences were completed when the cohort members were 15-16 years old. Inhalant use was categorized into four groups (never, once, 2-4 times, 5 times or more). Subsequent psychosis diagnoses (ICD-10) until age 30 years were obtained from national registers. Cox regression analysis was used to examine the association between adolescent inhalant use and risk of psychosis. RESULTS During the observation period 124 individuals were diagnosed with incident psychosis. Overall, there were 225 (3.4%) subjects with any inhalant use, 18 (8.0%) of whom were diagnosed with psychosis during the follow up. Of non-inhalant users (n = 6317) 106 (1.7%) were diagnosed with psychosis. Compared to non-users, those using inhalants had increased risk of incident psychosis with most frequent inhalant use associated with the greatest risk (unadjusted HR = 9.46; 3.86-23.20). After adjusting for baseline psychotic experiences, other substance use, comorbid mental disorder and parental substance abuse, the increased risk of psychosis persisted (HR = 3.06; 1.05-8.95). Furthermore, a dose-response effect between inhalant use and risk of psychosis was identified (OR = 2.34; 1.83-2.99). CONCLUSIONS Inhalant use in adolescence was independently associated with incident psychosis. The adverse health outcomes associated with adolescent inhalant use provide compelling reasons for implementation of policies to reduce the use of volatile substances in adolescents.
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Affiliation(s)
- Antti Mustonen
- Center for Life Course Health Research, University of Oulu, Oulu, Finland; Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
| | - Solja Niemelä
- Department of Psychiatry, Research Unit of Clinical Neuroscience, University of Oulu, Oulu, Finland; Department of Psychiatry, Lapland Hospital District, Rovaniemi, Finland
| | - John J McGrath
- Queensland Brain Institute, The University of Queensland, St. Lucia, Queensland, Australia; Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, Queensland, Australia; National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Denmark
| | - Graham K Murray
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Tanja Nordström
- Center for Life Course Health Research, University of Oulu, Oulu, Finland; Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Pirjo Mäki
- Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland; Department of Psychiatry, Research Unit of Clinical Neuroscience, University of Oulu, Oulu, Finland; Department of Psychiatry, Oulu University Hospital, Oulu, the Northern Ostrobothnia Hospital District, Finland; Department of Psychiatry, Länsi-Pohja healthcare district, Finland; Department of Psychiatry, the Middle Ostrobothnia Central Hospital, Soite, Finland; Mental Health Services, Basic Health Care District of Kallio, Finland; Department of Psychiatry, Kainuu Central Hospital, Kainuu social and healthcare district, Kajaani, Finland; Mental Health Services, Joint Municipal Authority of Wellbeing in Raahe District, Finland
| | - Jouko Miettunen
- Center for Life Course Health Research, University of Oulu, Oulu, Finland; Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - James G Scott
- Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, Queensland, Australia; Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia; Metro North Mental Health, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
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8
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Crossin R, Lawrence AJ, Andrews ZB, Churilov L, Duncan JR. Growth changes after inhalant abuse and toluene exposure: A systematic review and meta-analysis of human and animal studies. Hum Exp Toxicol 2018; 38:157-172. [PMID: 30062923 DOI: 10.1177/0960327118792064] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Inhalant abuse is a significant public health issue, particularly for adolescents, the predominant group of inhalant users. Adolescence is a critical growth period, and inhalant abuse has been associated with growth impairments, including reduced body weight and height. However, the extent to which inhalant abuse affects growth remains unquantified, and potential moderators remain unknown. To address this knowledge gap, a systematic review and meta-analysis of clinical human and preclinical animal studies utilizing toluene exposure (the primary solvent in abused products) was conducted. Five-hundred and sixty-nine studies were screened; 31 met inclusion criteria, yielding 64 toluene-control comparisons for body weight and 6 comparisons for height. Toluene exposure was negatively associated with body weight ( d = -0.73) and height ( d = -0.69). Concentration of inhaled toluene, but not duration, moderated the effect of toluene exposure on body weight, with more severe impairments at higher concentrations. Differences in effect size for body weight were observed for study characteristic subgroups including sex, age at first exposure, administration route and species. However, these findings should be interpreted cautiously due to low study numbers. Growth impairments, particularly during adolescence, can cause long-term health consequences. These effects on growth are therefore an important clinical outcome for individuals with a history of inhalant abuse.
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Affiliation(s)
- R Crossin
- 1 Addiction Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Victoria, Australia.,2 Eastern Health Clinical School, Monash University, Clayton, Victoria, Australia
| | - A J Lawrence
- 1 Addiction Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Victoria, Australia.,3 Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Z B Andrews
- 4 Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - L Churilov
- 3 Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - J R Duncan
- 1 Addiction Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Victoria, Australia.,5 School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
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Ranson MA, Del Bigio MR. Chronic near lifetime toluene exposure in rodents does not replicate solvent abuse leukoencephalopathy in humans. Neurotoxicology 2018; 69:260-265. [PMID: 30056179 DOI: 10.1016/j.neuro.2018.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 10/28/2022]
Abstract
Toluene is an organic solvent used in industry and as a substance of abuse. The latter situation may be associated with a leukoencephalopathy characterized by white matter atrophy, multifocal myelin loss, and macrophages that contain birefringent granular inclusions. To determine if rodents can develop the same white matter damage, we studied archived rodent brain samples from three near-lifetime toluene carcinogenicity experiments. Rats and mice were exposed to toluene via an inhalation chamber at 1200 ppm for 6.5 h daily, 5 days per week, for 103 weeks. Rats were exposed to toluene via oral gavage of 800 mg/kg, 4 days per week, for 104 weeks. In gavage-exposed brains, immunohistochemical staining was used to detect reactive astroglial and microglial changes, neuron populations, and cytochrome P450 upregulation. None of the white matter changes reported in human toluene abuse were identified in the rat or mouse brains. In a blinded analysis, a mild widespread increase in reactive microglia was detected in female rats that received toluene by gavage at 800 mg/kg. However, no significant differences were detected in neurons or astrocytes. Potential reasons for the absence of changes are discussed. We conclude that rodent studies designed to study carcinogenicity of toluene might not adequately model abuse exposure.
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Affiliation(s)
- Marc A Ranson
- Department of Pathology, University of Manitoba, Winnipeg Canada
| | - Marc R Del Bigio
- Department of Pathology, University of Manitoba, Winnipeg Canada; Children's Hospital Research Institute of Manitoba, Winnipeg Canada.
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10
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Crossin R, Andrews ZB, Sims NA, Pang T, Mathai M, Gooi JH, Stefanidis A, Oldfield BJ, Lawrence AJ, Duncan JR. Adolescent Inhalant Abuse Results in Adrenal Dysfunction and a Hypermetabolic Phenotype with Persistent Growth Impairments. Neuroendocrinology 2018; 107:340-354. [PMID: 30208370 DOI: 10.1159/000493686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/12/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Abuse of toluene products (e.g., glue-sniffing) primarily occurs during adolescence and has been associated with appetite suppression and weight impairments. However, the metabolic phenotype arising from adolescent inhalant abuse has never been fully characterised, and its persistence during abstinence and underlying mechanisms remain unknown. METHODS Adolescent male Wistar rats (post-natal day 27) were exposed to inhaled toluene (10,000 ppm) (n = 32) or air (n = 48) for 1 h/day, 3 days/week for 4 weeks, followed by 4 weeks of abstinence. Twenty air rats were pair-fed to the toluene group, to differentiate the direct effects of toluene from under-nutrition. Food intake, weight, and growth were monitored. Metabolic hormones were measured after exposure and abstinence periods. Energy expenditure was measured using indirect calorimetry. Adrenal function was assessed using adrenal histology and hormone testing. RESULTS Inhalant abuse suppressed appetite and increased energy expenditure. Reduced weight gain and growth were observed in both the toluene and pair-fed groups. Compared to the pair-fed group, and despite normalisation of food intake, the suppression of weight and growth for toluene-exposed rats persisted during abstinence. After exposure, toluene-exposed rats had low fasting blood glucose and insulin compared to the air and pair-fed groups. Consistent with adrenal insufficiency, adrenal hypertrophy and increased basal adrenocorticotropic hormone were observed in the toluene-exposed rats, despite normal basal corticosterone levels. CONCLUSIONS Inhalant abuse results in negative energy balance, persistent growth impairment, and endocrine changes suggestive of adrenal insufficiency. We conclude that adrenal insufficiency contributes to the negative energy balance phenotype, potentially presenting a significant additional health risk for inhalant users.
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Affiliation(s)
- Rose Crossin
- Addiction Neuroscience, Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria,
- Eastern Health Clinical School, Monash University, Box Hill, Victoria,
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Natalie A Sims
- St Vincent's Institute of Medical Research and Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Terence Pang
- Addiction Neuroscience, Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
| | | | - Jonathan H Gooi
- Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
| | - Aneta Stefanidis
- Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Brian J Oldfield
- Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Andrew J Lawrence
- Addiction Neuroscience, Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jhodie R Duncan
- Addiction Neuroscience, Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
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Braunscheidel KM, Gass JT, Mulholland PJ, Floresco SB, Woodward JJ. Persistent cognitive and morphological alterations induced by repeated exposure of adolescent rats to the abused inhalant toluene. Neurobiol Learn Mem 2017; 144:136-146. [PMID: 28720405 PMCID: PMC5583007 DOI: 10.1016/j.nlm.2017.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 07/07/2017] [Accepted: 07/14/2017] [Indexed: 12/20/2022]
Abstract
While thepsychoactive inhalant toluene causes behavioral effects similarto those produced by other drugs of abuse, the persistent behavioral and anatomical abnormalities induced by toluene exposure are not well known. To mimic human "binge-like" inhalant intoxication, adolescent, male Sprague-Dawley rats were exposed to toluene vapor (5700ppm) twice daily for five consecutive days. These rats remained in their home cages until adulthood (P60), when they were trained in operant boxes to respond to a palatable food reward and then challenged with several different cognitive tasks. Rats that experienced chronic exposure to toluene plus abstinence ("CTA") showed enhanced performance in a strategy set-shifting task using a between-session, but not a within-session test design. CTA also blunted operant and classical conditioning without affecting responding during a progressive ratio task. While CTA rats displayed normal latent inhibition, previous exposure to a non-reinforced cue enhanced extinction of classically conditioned approach behavior of these animals compared to air controls. To determine whether CTA alters the structural plasticity of brain areas involved in set-shifting and appetitive behaviors, we quantified basal dendritic spine morphology in DiI-labeled pyramidal neurons in layer 5 of the medial prefrontal cortex (mPFC) and medium spiny neurons in the nucleus accumbens (NAc). There were no changes in dendritic spine density or subtype in the mPFC of CTA rats while NAc spine density was significantly increased due to an enhanced prevalence of long-thin spines. Together, these findings suggest that the persistent effects of CTA on cognition are related to learning and memory consolidation/recall, but not mPFC-dependent behavioral flexibility.
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Affiliation(s)
- K M Braunscheidel
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
| | - J T Gass
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 67 President Street, Charleston, SC 29425, USA
| | - P J Mulholland
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 67 President Street, Charleston, SC 29425, USA
| | - S B Floresco
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada
| | - J J Woodward
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 67 President Street, Charleston, SC 29425, USA.
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12
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Orthostatic tremor secondary to recreational use of solvents. NEUROLOGÍA (ENGLISH EDITION) 2017. [DOI: 10.1016/j.nrleng.2015.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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13
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Furlong TM, Duncan JR, Corbit LH, Rae CD, Rowlands BD, Maher AD, Nasrallah FA, Milligan CJ, Petrou S, Lawrence AJ, Balleine BW. Toluene inhalation in adolescent rats reduces flexible behaviour in adulthood and alters glutamatergic and GABAergic signalling. J Neurochem 2016; 139:806-822. [PMID: 27696399 DOI: 10.1111/jnc.13858] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 09/15/2016] [Accepted: 09/18/2016] [Indexed: 12/24/2022]
Abstract
Toluene is a commonly abused inhalant that is easily accessible to adolescents. Despite the increasing incidence of use, our understanding of its long-term impact remains limited. Here, we used a range of techniques to examine the acute and chronic effects of toluene exposure on glutameteric and GABAergic function, and on indices of psychological function in adult rats after adolescent exposure. Metabolomics conducted on cortical tissue established that acute exposure to toluene produces alterations in cellular metabolism indicative of a glutamatergic and GABAergic profile. Similarly, in vitro electrophysiology in Xenopus oocytes found that acute toluene exposure reduced NMDA receptor signalling. Finally, in an adolescent rodent model of chronic intermittent exposure to toluene (10 000 ppm), we found that, while toluene exposure did not affect initial learning, it induced a deficit in updating that learning when response-outcome relationships were reversed or degraded in an instrumental conditioning paradigm. There were also group differences when more effort was required to obtain the reward; toluene-exposed animals were less sensitive to progressive ratio schedules and to delayed discounting. These behavioural deficits were accompanied by changes in subunit expression of both NMDA and GABA receptors in adulthood, up to 10 weeks after the final exposure to toluene in the hippocampus, prefrontal cortex and ventromedial striatum; regions with recognized roles in behavioural flexibility and decision-making. Collectively, our data suggest that exposure to toluene is sufficient to induce adaptive changes in glutamatergic and GABAergic systems and in adaptive behaviour that may underlie the deficits observed following adolescent inhalant abuse, including susceptibility to further drug-use.
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Affiliation(s)
- Teri M Furlong
- Brain & Mind Centre, University of Sydney, Sydney, New South Wales, Australia.,School of Psychology, University of Sydney, Sydney, New South Wales, Australia
| | - Jhodie R Duncan
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Laura H Corbit
- School of Psychology, University of Sydney, Sydney, New South Wales, Australia
| | - Caroline D Rae
- Neuroscience Research Australia, Randwick, New South Wales, Australia.,School of Medical Sciences, University of NSW, Kensington, New South Wales, Australia
| | - Benjamin D Rowlands
- Neuroscience Research Australia, Randwick, New South Wales, Australia.,School of Medical Sciences, University of NSW, Kensington, New South Wales, Australia
| | - Anthony D Maher
- Neuroscience Research Australia, Randwick, New South Wales, Australia
| | | | - Carol J Milligan
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Bernard W Balleine
- Brain & Mind Centre, University of Sydney, Sydney, New South Wales, Australia.,School of Psychology, University of NSW, Kensington, New South Wales, Australia
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14
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Cruz Tabuenca H, Camacho Velásquez JL, Rivero Sanz E, Sánchez Valiente S, López Del Val J. Orthostatic tremor secondary to recreational use of solvents. Neurologia 2015; 32:401-403. [PMID: 26699207 DOI: 10.1016/j.nrl.2015.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/23/2015] [Accepted: 10/09/2015] [Indexed: 10/22/2022] Open
Affiliation(s)
- H Cruz Tabuenca
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
| | - J L Camacho Velásquez
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España.
| | - E Rivero Sanz
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
| | - S Sánchez Valiente
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
| | - J López Del Val
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
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15
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Dick ALW, Simpson A, Qama A, Andrews Z, Lawrence AJ, Duncan JR. Chronic intermittent toluene inhalation in adolescent rats results in metabolic dysfunction with altered glucose homeostasis. Br J Pharmacol 2015; 172:5174-87. [PMID: 26282596 DOI: 10.1111/bph.13284] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 08/09/2015] [Accepted: 08/10/2015] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Abuse of toluene-containing inhalants is an increasing public health problem, especially among adolescents. Abuse during adolescence is associated with emaciation, while industrial exposure leads to altered glycaemic control suggesting metabolic instability. However, the relationship between adolescent inhalant abuse and metabolic dysfunction remains unknown. EXPERIMENTAL APPROACH To model human abuse patterns, we exposed male adolescent Wistar rats [postnatal day (PND) 27] to chronic intermittent inhaled toluene (CIT, 10,000 ppm) or air (control) for 1 h·day(-1) , three times a week for 4 weeks. Feeding and body composition were monitored. After 4 weeks, circulating metabolic hormone concentrations and responses to a glucose tolerance test (GTT) were measured. Dietary preference was measured by giving animals access to either a 'western diet' plus standard chow (WC + SC) or standard chow alone during 4 weeks of abstinence. Metabolic hormones and GTT were subsequently measured. KEY RESULTS Adolescent CIT exposure significantly retarded weight gain, altered body composition, circulating metabolic hormones and responses to a GTT. While reduced body weight persisted, responses to a GTT and circulating hormones appeared to normalize for animals on standard chow following abstinence. In CIT-exposed WC + SC rats, we observed impaired glucose tolerance associated with altered metabolic hormones. Analysis of hypothalamic genes revealed differential expression profiles in CIT-exposed rats following both the exposure period and abstinence, suggesting a central contribution to inhalant-induced metabolic dysfunction. CONCLUSION AND IMPLICATIONS CIT exposure during adolescence has long-term effects on metabolic function, which may increase the risk of disorders related to energy balance and glycaemic control.
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Affiliation(s)
- A L W Dick
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic., Australia.,Department of Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - A Simpson
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic., Australia
| | - A Qama
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic., Australia
| | - Z Andrews
- Department of Physiology, Monash University, Clayton, Vic., Australia
| | - A J Lawrence
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic., Australia
| | - J R Duncan
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic., Australia.,Department Anatomy and Neuroscience, University of Melbourne, Melbourne, Vic., Australia
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16
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Dick ALW, Pooters T, Gibbs S, Giles E, Qama A, Lawrence AJ, Duncan JR. NMDA receptor binding is reduced within mesocorticolimbic regions following chronic inhalation of toluene in adolescent rats. Brain Res 2015; 1624:239-252. [DOI: 10.1016/j.brainres.2015.07.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 07/21/2015] [Accepted: 07/23/2015] [Indexed: 11/16/2022]
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17
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Abnormal white matter integrity and impairment of cognitive abilities in adolescent inhalant abusers. Neurotoxicol Teratol 2014; 47:89-95. [PMID: 25479538 DOI: 10.1016/j.ntt.2014.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 11/24/2014] [Accepted: 11/24/2014] [Indexed: 01/22/2023]
Abstract
Inhalant abuse represents a major health problem especially among adolescents and young adults. However, less is known about white matter (WM) microstructure in adolescent inhalant abusers. In the present study, we used diffusion tensor imaging (DTI) to study WM changes in adolescent inhalant abusers compared with healthy controls. We also tested whether there was any relationship between WM integrity and neuropsychological measures in adolescent inhalant abusers. The study included 19 adolescent inhalant abusers and 19 healthy control subjects. Whole brain analysis of WM microstructure was performed using tract-based spatial statistics (TBSS) to detect abnormal WM regions between groups. Wisconsin card sorting test (WCST) and Stroop test were used to measure neuropsychological performance. We found that adolescent inhalant abuser group had significantly higher axial diffusivity (AD) values in left parietal, occipital and temporal WM than in healthy control group. Inhalant abuser and control groups did not differ significantly on fractional anisotropy (FA) and radial diffusivity (RD) values. Adolescent inhalant abusers showed worse performance when compared with control group in WCST and Stroop test. There was no significant correlation of AD values in significant clusters with neuropsychological test performances within the two groups. We only found discrete impairments in neuropsychological test performance and WM integrity in adolescent inhalant abusers compared with healthy control subjects and we were not able to demonstrate a direct correlation between WM alterations and neurocognitive performance. Future work is required to longitudinally evaluate brain abnormalities through methods assessing brain structure, function and connectivity.
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18
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Dick ALW, Lawrence AJ, Duncan JR. Chronic intermittent toluene inhalation initiated during adolescence in rats does not alter voluntary consumption of ethanol in adulthood. Alcohol 2014; 48:561-9. [PMID: 25212750 DOI: 10.1016/j.alcohol.2014.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Voluntary inhalation of organic solvents, such as toluene, is particularly prevalent in adolescent populations and is considered to be a contributing factor to substance use and dependence later in life. While inhalants are often the initial "drug" experienced during this period, alcohol is another substance readily abused by adolescent populations. Although both substances are thought to have similar actions within the brain, our understanding of the implications of adolescent inhalant abuse upon subsequent exposure to alcohol remains to be investigated. Thus, this study aimed to assess locomotor responses to acute ethanol and voluntary ethanol consumption following a period of toluene inhalation throughout adolescence/early adulthood. Adolescent male Wistar rats (postnatal day [PN] 27) inhaled air or toluene (3000 ppm) for 1 h/day, 3 days/week for 4 (PN 27-52) or 8 weeks (PN 27-80) to mimic the patterns observed in human inhalant abusers. Following the exposure period, cross-sensitization to acute ethanol challenge (0.5 g/kg, intra-peritoneally [i.p.]), and voluntary consumption of 20% ethanol in a chronic intermittent 2-bottle choice paradigm, were assessed. Hepatic ethanol and acetaldehyde metabolism and liver histopathology were also investigated. Chronic intermittent toluene (CIT) exposure throughout adolescence for up to 8 weeks did not alter the behavioral response to acute ethanol or voluntary consumption of ethanol in adulthood, although an age-dependent effect on ethanol consumption was observed (p<0.05). Both liver function and pathology did not differ between treatment groups. Thus, in the paradigm employed, CIT exposure throughout adolescence and early adulthood did not predispose rats to subsequent locomotor sensitivity or voluntary consumption of ethanol in adulthood.
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Affiliation(s)
- Alec L W Dick
- Florey Institute of Neuroscience & Mental Health, Australia; Florey Department of Neuroscience and Mental Health, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience & Mental Health, Australia; Florey Department of Neuroscience and Mental Health, Australia.
| | - Jhodie R Duncan
- Florey Institute of Neuroscience & Mental Health, Australia; Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria 3010 Australia.
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19
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Encephalopathy and Neuropathy due to Glue, Paint Thinner, and Gasoline Sniffing in Trinidad and Tobago-MRI Findings. Case Rep Neurol Med 2014; 2014:850109. [PMID: 25045557 PMCID: PMC4087279 DOI: 10.1155/2014/850109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/05/2014] [Indexed: 11/29/2022] Open
Abstract
A 29-year-old male petrol station pump attendant was admitted with ataxia and clinical evidence of a sensorimotor polyneuropathy which developed over the preceding 3 months. He had cognitive dysfunction, hearing loss, and cerebellar clinical abnormalities that came on slowly over the three years. He had a fifteen-year history of sniffing mostly glue, occasionally paint thinners, and, in the recent two years, gasoline. Magnetic resonance brain imaging showed abnormalities of the cerebral cortex, cerebral white matter, corpus callosum, hippocampus, brainstem and cerebellar atrophy, hypointensities of basal ganglia, red nuclei, and substantia nigra as previously described in toluene sniffing. Abstinence for six months led to partial clinical improvement. Clinicians need to be aware of this preventable entity which has peculiar radiological findings which are being increasingly accepted as typical.
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20
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21
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Specific impairments in instrumental learning following chronic intermittent toluene inhalation in adolescent rats. Psychopharmacology (Berl) 2014; 231:1531-42. [PMID: 24322667 DOI: 10.1007/s00213-013-3363-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/18/2013] [Indexed: 01/17/2023]
Abstract
RATIONALE Inhalant abuse is prevalent in adolescent populations, with chronic use resulting in neurobiological and cognitive abnormalities in adulthood. However, the nature and persistence of cognitive dysfunction, particularly following adolescent inhalant abuse, remain equivocal. OBJECTIVE The present study assessed specific cognitive processes beginning in late adolescence and adulthood following adolescent inhalation of toluene, a main component of many compounds readily abused. METHODS Adolescent male Wistar rats (postnatal day (PN) 27) were exposed to chronic intermittent inhaled toluene (10,000 ppm) for 1 h/day, 3 days/week for 4 weeks (PN 27-52) to mimic the patterns observed in human adolescent inhalant abusers. Following toluene exposure, motor and cognitive function was assessed. RESULTS Adolescent toluene exposure did not alter motor learning in the Rotarod task (PN 58) or acquisition, reversal, or retention of spatial learning in the Morris water maze (PN 55-64). In contrast, it delayed acquisition of instrumental responding for sucrose (5 % w/v) and impaired operant reversal learning and cue-induced reinstatement of sucrose seeking in adulthood (PN 57-100). CONCLUSION This study demonstrates that exposure to toluene at an abuse concentration during adolescence results in specific impairments in aspects of instrumental learning, without altering motor function and spatial learning in late adolescence/early adulthood. Our data imply that persistent alterations in reward processing may occur following adolescent inhalant misuse.
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22
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Duncan JR, Gibbs SJ, Lawrence AJ. Chronic intermittent toluene inhalation in adolescent rats alters behavioural responses to amphetamine and MK801. Eur Neuropsychopharmacol 2014; 24:480-6. [PMID: 23810580 DOI: 10.1016/j.euroneuro.2013.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 05/29/2013] [Accepted: 06/04/2013] [Indexed: 02/03/2023]
Abstract
Abuse of toluene-containing inhalants is common during adolescence, with ongoing chronic misuse associated with adverse outcomes and increased risk for addictive behaviours in adulthood. However, the mechanisms mediating the adaptive processes related to these outcomes are not well defined. To model human abuse patterns we exposed male adolescent Wistar rats (postnatal day 27) to chronic intermittent inhaled toluene (CIT, 10,000 ppm) or air (control) for 1h/day, three times/week for 3 weeks. The effects of CIT on behaviour and recovery were monitored. Locomotor activity was recorded following two consecutive injections of amphetamine (1mg/kg, i.p.) 72 and 96 h after the last exposure. This was followed with injection of the NMDA receptor antagonist MK801 (0.5mg/kg, i.p.) 20 days after the last exposure. CIT resulted in a significant and persistent retardation in weight gain during the exposure period and abstinence (p<0.05). Repeated exposure resulted in tolerance to the onset of toluene-induced behaviours and recovery latency. There was a reduction in the acute stimulant effects of amphetamine in CIT-exposed animals and an increase in the magnitude of locomotor activity (p<0.0125) following a subsequent exposure when compared to the responses observed in controls; this was associated with altered locomotor responses to MK801. Repeated exposure to CIT during adolescence alters parameters of growth, as measured by body weight, and leads to tolerance, indicating that increasing concentrations of the compound may be needed to reach the same behavioural state. Toluene during this period also alters responses to a psychostimulant which may be related to long-term glutamatergic dysfunction.
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Affiliation(s)
- Jhodie Rubina Duncan
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic. 3010, Australia; Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Vic. 3010, Australia.
| | - Sarah Jane Gibbs
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic. 3010, Australia
| | - Andrew John Lawrence
- Division of Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic. 3010, Australia; Centre for Neuroscience Research, University of Melbourne, Melbourne, Vic. 3010, Australia
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23
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White matter microstructure alterations: a study of alcoholics with and without post-traumatic stress disorder. PLoS One 2013; 8:e80952. [PMID: 24260518 PMCID: PMC3832443 DOI: 10.1371/journal.pone.0080952] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 10/13/2013] [Indexed: 02/07/2023] Open
Abstract
Many brain imaging studies have demonstrated reductions in gray and white matter volumes in alcoholism, with fewer investigators using diffusion tensor imaging (DTI) to examine the integrity of white matter pathways. Among various medical conditions, alcoholism and post-traumatic stress disorder (PTSD) are two comorbid diseases that have similar degenerative effects on the white matter integrity. Therefore, understanding and differentiating these effects would be very important in characterizing alcoholism and PTSD. Alcoholics are known to have neurocognitive deficits in decision-making, particularly in decisions related to emotionally-motivated behavior, while individuals with PTSD have deficits in emotional regulation and enhanced fear response. It is widely believed that these types of abnormalities in both alcoholism and PTSD are related to fronto-limbic dysfunction. In addition, previous studies have shown cortico-limbic fiber degradation through fiber tracking in alcoholism. DTI was used to measure white matter fractional anisotropy (FA), which provides information about tissue microstructure, possibly indicating white matter integrity. We quantitatively investigated the microstructure of white matter through whole brain DTI analysis in healthy volunteers (HV) and alcohol dependent subjects without PTSD (ALC) and with PTSD (ALC+PTSD). These data show significant differences in FA between alcoholics and non-alcoholic HVs, with no significant differences in FA between ALC and ALC+PTSD in any white matter structure. We performed a post-hoc region of interest analysis that allowed us to incorporate multiple covariates into the analysis and found similar results. HV had higher FA in several areas implicated in the reward circuit, emotion, and executive functioning, suggesting that there may be microstructural abnormalities in white matter pathways that contribute to neurocognitive and executive functioning deficits observed in alcoholics. Furthermore, our data do not reveal any differences between ALC and ALC+PTSD, suggesting that the effect of alcohol on white matter microstructure may be more significant than any effect caused by PTSD.
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Samuel-Herter SR, Slaght SL, McKay BE. Age-dependent time courses of recovery for motor functions following acute toluene intoxication in rats. Dev Psychobiol 2013; 56:657-73. [PMID: 23765908 DOI: 10.1002/dev.21134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Accepted: 04/12/2013] [Indexed: 12/13/2022]
Abstract
Toluene is a psychoactive chemical found in many household products including adhesives and thinners. Inhalation of these vapors can cause euphoria and impairments in motor control and neurological functioning. Misuse and abuse of toluene is most common in children, which may in part be due to an age-dependent neurobehavioral sensitivity to toluene. Here we assessed the effects of acute binge-like toluene inhalations (15 or 30 min; ∼5,000 ppm) on tasks that examine locomotion, exploration, balance, gait, and neurological functioning for adolescent (1 month), young adult (2-3 months), adult (5-6 months), and older adult (10-12 months) rats. Both motor and neurological functions were impaired following acute toluene inhalation at all ages. However, only the duration to recover from deficits in motor functions differed among age groups, with adolescent and young adult rats requiring notably longer recovery times than older rats. Our results are suggestive of an age-dependent vulnerability to the intoxicating effects of toluene.
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Affiliation(s)
- Susan R Samuel-Herter
- Department of Psychology, Wilfrid Laurier University, 75 University Ave W., Waterloo, Ontario, Canada, N2L 3C5
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25
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Abstract
The brain is the primary target of toluene (methylbenzene), the major solvent in spray paint and a constituent of many other easily obtained commercial and industrial products. The effects of acute intoxication can be dramatic and the lasting adverse effects of inhalants may be highly injurious. Mental status alterations range from acute confusional state to coma. Toluene abuse effects on white matter are demonstrable neuroradiologically and neuropathologically, and have important neurobehavioral consequences.
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Affiliation(s)
- Christopher M Filley
- Behavioral Neurology Section, University of Colorado School of Medicine, 12631 East 17th Avenue, MS B185, Aurora, CO 80045, USA.
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