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Gallardo-Ortíz IA, Oros-González A, Rodríguez-Manzo G, Garduño-Gutiérrez R, Aragón-Martínez A, Páez-Martínez N. Effect of exercise duration on toluene-induced locomotor sensitization in mice: a focus on the Renin Angiotensin System. Psychopharmacology (Berl) 2024:10.1007/s00213-024-06626-5. [PMID: 38839630 DOI: 10.1007/s00213-024-06626-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/23/2024] [Indexed: 06/07/2024]
Abstract
RATIONALE Exercise attenuates addictive behavior; however, little is known about the contribution of exercise duration to this positive effect. The Renin Angiotensin System (RAS) has been implicated both in addictive responses and in the beneficial effects of exercise; though, its role in the advantageous effects of exercise on toluene-induced addictive responses has not been explored. OBJECTIVES To evaluate the impact of different exercise regimens in mitigating the expression of toluene-induced locomotor sensitization and to analyze changes in RAS elements' expression at the mesocorticolimbic system after repeated toluene exposure and following voluntary wheel running in toluene-sensitized animals. METHODS Toluene-induced addictive-like response was evaluated with a locomotor sensitization model in mice. Toluene-sensitized animals had access to running wheels 1, 2, 4 or 24 h/day for 4 weeks; thereafter, locomotor sensitization expression was evaluated after a toluene challenge. RAS elements (ACE and ACE2 enzymes; AT1, AT2 and Mas receptors) expression was determined by Western blot in the VTA, NAc and PFCx of toluene-sensitized mice with and without exercise. RESULTS Individual differences in toluene-induced locomotor sensitization development were observed. Access to wheel running 1 and 2 h/day reduced but 4 and 24 h/day completely blocked locomotor sensitization expression. Repeated toluene exposure changed RAS elements' expression in the VTA, NAc and PFCx, while exercise mainly modified ACE and AT1 in air-exposed and toluene-sensitized mice. CONCLUSIONS Inhalant-exposed animals show different sensitization phenotypes. Exercise duration determined its efficacy to attenuate the addictive-like response. Toluene exposure and exercise each modified RAS, the latter also modifying toluene-induced changes.
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Affiliation(s)
- Itzell A Gallardo-Ortíz
- Unidad de Biomedicina, Carrera de Enfermería, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, Estado de México, México
| | - Alain Oros-González
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | - Gabriela Rodríguez-Manzo
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav), Sede Sur, Ciudad de México, México
| | - René Garduño-Gutiérrez
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav), Sede Sur, Ciudad de México, México
| | - Andrés Aragón-Martínez
- Unidad de Biomedicina, Carrera de Biología, Laboratorio de Gametos y Desarrollo Tecnológico, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, Estado de México, México
| | - Nayeli Páez-Martínez
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México.
- Laboratorio Integrativo para el Estudio de Sustancias Inhalables Adictivas, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz", Ciudad de México, México.
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García-Jácome D, Martínez-Mota L, Páez-Martínez N. Effects of housing condition on the development and persistence of addictive-like behavior induced by toluene. Neurotoxicology 2024; 103:9-15. [PMID: 38801998 DOI: 10.1016/j.neuro.2024.05.004] [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: 03/27/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 05/29/2024]
Abstract
Environmental factors can modify addictive responses induced by drugs of abuse; however, little is known about the impact of environmental conditions on behavioral responses induced by inhalants. In this study, we analyzed the effects of housing conditions, considering environmental enrichment (EE; n = 10), social isolation (SI; n = 10), and standard housing (STD; n = 10), as positive, negative, and control environments, respectively, on the development and persistence of behavioral sensitization induced by toluene. Mice exposed to air were used as a comparative control groups for each housing condition (EE: n = 11, SI: n = 10 and STD: n = 11). Results showed that a history of toluene exposure induced the development of locomotor sensitization in mice, independent of their housing conditions. However, SI increased the expression of behavioral sensitization to toluene after a drug-free period.
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Affiliation(s)
- David García-Jácome
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Salvador Díaz Mirón, Casco de Santo Tomas, Miguel Hidalgo, 11340, Ciudad de México, México
| | - Lucía Martínez-Mota
- Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz. Calzada México-Xochimilco 101, Colonia San Lorenzo Huipulco, Tlalpan, 14370, Ciudad de México, México
| | - Nayeli Páez-Martínez
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Salvador Díaz Mirón, Casco de Santo Tomas, Miguel Hidalgo, 11340, Ciudad de México, México; Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz. Calzada México-Xochimilco 101, Colonia San Lorenzo Huipulco, Tlalpan, 14370, Ciudad de México, México.
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Davidson CJ, Hannigan JH, Perrine SA, Bowen SE. Abuse-like toluene exposure during early adolescence alters subsequent ethanol and cocaine behavioral effects and brain monoamines in male mice. Neurotoxicol Teratol 2024; 101:107317. [PMID: 38199311 DOI: 10.1016/j.ntt.2023.107317] [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: 06/21/2023] [Revised: 12/01/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024]
Abstract
Currently, there is a gap in understanding the neurobiological impact early adolescent toluene exposure has on subsequent actions of other drugs. Adolescent (PND 28-32) male Swiss-Webster mice (N = 210) were exposed to 0, 2000, or 4000 ppm of toluene vapor for 30 min/day for 5 days. Immediately following the last toluene exposure (PND 32; n = 15) or after a short delay (PND 35; n = 15), a subset of subjects' brains was collected for monoamine analysis. Remaining mice were assigned to one of two abstinence periods: a short 4-day (PND 36) or long 12-day (PND 44) delay after toluene exposure. Mice were then subjected to a cumulative dose response assessment of either cocaine (0, 2.5, 5, 10, 20 mg/kg; n = 60), ethanol (0, 0.5, 1, 2, 4 g/kg; n = 60), or saline (5 control injections; n = 60). Toluene concentration-dependently increased locomotor activity during exposure. When later challenged, mice exposed previously to toluene were significantly less active after cocaine (10 and 20 mg/kg) compared to air-exposed controls. Animals were also less active at the highest dose of alcohol (4 g/kg) following prior exposure to 4000 ppm when compared to air-exposed controls. Analysis of monoamines and their metabolites using High Pressure Liquid Chromatography (HPLC) within the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), dorsal striatum (dSTR), and ventral tegmental area (VTA) revealed subtle effects on monoamine or metabolite levels following cumulative dosing that varied by drug (cocaine and ethanol) and abstinence duration. Our results suggest that early adolescent toluene exposure produces behavioral desensitization to subsequent cocaine-induced locomotor activity with subtle enhancement of ethanol's depressive effects and less clear impacts on levels of monoamines.
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Affiliation(s)
- Cameron J Davidson
- Department of Psychology, Wayne State University, Detroit, MI, USA; School of Medicine, Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, USA.
| | - John H Hannigan
- Department of Psychology, Wayne State University, Detroit, MI, USA; School of Medicine, Department of Obstetrics & Gynecology, Wayne State University, Detroit, MI, USA; Merrill Palmer Skillman Institute for Child & Family Development, Wayne State University, Detroit, MI, USA; Center for Urban Responses to Environmental Stressors, Wayne State University, Detroit, MI, USA
| | - Shane A Perrine
- School of Medicine, Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, USA
| | - Scott E Bowen
- Department of Psychology, Wayne State University, Detroit, MI, USA; Center for Urban Responses to Environmental Stressors, Wayne State University, Detroit, MI, USA; School of Medicine, Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, USA.
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4
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Soberanes-Chávez P, de Gortari P, García-Luna C, Cruz SL. Repeated toluene and cyclohexane inhalation produces differential effects on HPA and HPT axes in adolescent male rats. Neurotoxicology 2023; 99:244-253. [PMID: 37944760 DOI: 10.1016/j.neuro.2023.11.003] [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: 08/15/2023] [Revised: 09/30/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023]
Abstract
Misused volatile solvents typically contain toluene (TOL) as the main psychoactive ingredient. Cyclohexane (CHX) can also be present and is considered a safer alternative. Solvent misuse often occurs at early stages of life, leading to permanent neurobehavioral impairment and growth retardation. However, a comprehensive examination of the effects of TOL and CHX on stress regulation and energy balance is lacking. Here, we compared the effect of a binge-pattern exposure to TOL or CHX (4,000 or 8,000 ppm) on body weight, food intake, the hypothalamus-pituitary-adrenal (HPA) and hypothalamus-pituitary-thyroid (HPT) axes in male adolescent Wistar rats. At 8,000 ppm, TOL decreased body weight gain without affecting food intake. In addition, TOL and CHX altered the HPA and HPT axes' function in a solvent- and concentration-dependent manner. The highest TOL concentration produced HPA axis hyperactivation in animals not subjected to stress, which was evidenced by increased corticotropin-releasing-factor (CRF) release from the median eminence (ME), elevated adrenocorticotropin hormone (ACTH) and corticosterone serum levels, and decreased CRF mRNA levels in the hypothalamic paraventricular nucleus (PVN). TOL (8,000 ppm) also increased triiodothyronine (T3) serum levels, decreased pro-thyrotropin-releasing-hormone (pro-TRH) mRNA transcription in the PVN, pro-TRH content in the ME, and serum thyroid stimulating hormone (TSH) levels. CHX did not affect the HPA axis. We propose that the increased HPT axis activity induced by TOL can be related to the impaired body weight gain associated with inhalant misuse. These findings may contribute to a better understanding of the effects of the misused solvents TOL and CHX.
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Affiliation(s)
- P Soberanes-Chávez
- Laboratorio de Neurofisiología Molecular, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, 14370, Mexico.
| | - P de Gortari
- Laboratorio de Neurofisiología Molecular, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, 14370, Mexico
| | - C García-Luna
- Laboratorio de Neurofisiología Molecular, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, 14370, Mexico
| | - S L Cruz
- Department of Pharmacobiology, Center for Research and Advanced Studies (Cinvestav), Calzada de los Tenorios 235, Tlalpan, CP 14330 Mexico City, Mexico
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Braunstein S, Bennett NC, Voigt C, Oosthuizen MK. Differential locomotor activity responses to day-time light intensity in juvenile and adult solitary Cape mole-rats, Georychus capensis (Rodentia: Bathyergidae). Chronobiol Int 2023; 40:1084-1096. [PMID: 37667495 DOI: 10.1080/07420528.2023.2253298] [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: 06/13/2023] [Revised: 08/11/2023] [Accepted: 08/24/2023] [Indexed: 09/06/2023]
Abstract
The Cape mole-rat (Georychus capensis) is a solitary, strictly subterranean rodent that is responsive to light and entrains to photic cues despite having a reduced visual system. Circadian entrainment is maintained throughout life, but age can alter the amplitude of the response and re-entrainment time. Mole-rats are long-lived for their size which raises questions regarding the robustness of their circadian rhythms and how impacts their locomotor activity rhythms. The locomotor activity rhythms of juvenile and adult Cape mole-rats were investigated. They were exposed to pre-experimental and post-experimental control cycles under fluorescent lights, six 12 h light:12 h dark cycles of decreasing intensities and a constant dark cycle (DD). All animals exhibited more activity during the dark phases of all light regimes. Juveniles were more active than adults and displayed more variable activity during both the light and dark phases. Adults exhibited relatively stable levels of activity under all experimental conditions, whereas juvenile activity decreased as the light intensity was reduced. The amplitude of Cape mole-rat rhythms was consistently low, but similar across light regimes and between adults and juveniles. Cape mole-rats have functional circadian systems, are primarily nocturnal and respond differentially to light intensity depending on their age. Light intensity does not affect the locomotor activity responses of Cape mole-rats in a predictable manner, and could indicate more complex interactions with light wavelengths. The circadian systems of juveniles appear to be more sensitive than those of adults, although the mechanism of the light response remains unclear.
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Affiliation(s)
- S Braunstein
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - N C Bennett
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - C Voigt
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - M K Oosthuizen
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
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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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7
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Zhvania MG, Pochkhidze N, Dashniani M, Tizabi Y, Japaridze N, Burjanadze M, Chilachava L. Short- and long-term effects of chronic toluene exposure on recognition memory in adolescent and adult male Wistar rats. Brain Res Bull 2022; 190:116-121. [PMID: 36156293 DOI: 10.1016/j.brainresbull.2022.09.016] [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: 03/24/2022] [Revised: 09/17/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022]
Abstract
Abuse of toluene-containing volatile inhalants, particularly among youth, is of significant medical and social concern worldwide. Teenagers constitute the most abundant users of toluene and the majority of adult abusers of toluene started as teenagers. Although the euphoric and neurotoxic effects of acute toluene have been widely studied, lasting effects of chronic toluene exposure, especially in various age groups, have not been well investigated. In this study, we used adolescent and adult male Wistar rats to evaluate the short- and long-term effects of chronic toluene on various behaviors including cognitive function. Daily exposure to toluene (2000 ppm) for 40 days (5min/day) resulted in age-dependent behavioral impairments. Specifically, adolescent animals showed recognition memory impairment the day after the last exposure, which had normalized by day 90 post- exposure, whereas such impairment in adult animals was still evident at day 90 post-exposure. Our data suggest that age-dependent responses should be taken into consideration in interventional attempts to overcome specific detrimental consequences of chronic toluene exposure.
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Affiliation(s)
- Mzia G Zhvania
- School of Natural Sciences and Medicine, Ilia State University. 3/5 K. Cholokashvili Avenue,0162 Tbilisi, Georgia; Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia.
| | - Nino Pochkhidze
- School of Natural Sciences and Medicine, Ilia State University. 3/5 K. Cholokashvili Avenue,0162 Tbilisi, Georgia; Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia
| | - Manana Dashniani
- Department of Behavior and Cognitive Functions, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia
| | - Yousef Tizabi
- Department of Pharmacology, Howard University College of Medicine, Washington, DC, USA
| | - Nadezhda Japaridze
- Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia; Medical School, New Vision University, 1A Evgeni Mikeladze Street, 0159 Tbilisi, Georgia
| | - Maia Burjanadze
- Department of Behavior and Cognitive Functions, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia
| | - Lela Chilachava
- School of Natural Sciences and Medicine, Ilia State University. 3/5 K. Cholokashvili Avenue,0162 Tbilisi, Georgia
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8
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A novel preclinical model of environment-like combined benzene, toluene, ethylbenzene, and xylenes (BTEX) exposure: Behavioral and neurochemical findings. Neurotoxicol Teratol 2022; 91:107076. [DOI: 10.1016/j.ntt.2022.107076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 01/14/2022] [Accepted: 02/08/2022] [Indexed: 12/07/2022]
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Svenson DW, Davidson CJ, Thakur C, Bowen SE. ACUTE EXPOSURE TO ABUSE-LIKE CONCENTRATIONS OF TOLUENE INDUCES INFLAMMATION IN MOUSE LUNGS AND BRAIN. J Appl Toxicol 2022; 42:1168-1177. [PMID: 34993988 DOI: 10.1002/jat.4285] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/12/2021] [Accepted: 12/23/2021] [Indexed: 11/11/2022]
Abstract
Toluene is an aromatic hydrocarbon commonly abused by young adolescents for its central nervous system depressant effects. While toluene's pharmacological effects at high concentrations are relatively well known, few studies have assessed toluene's effects on lung and brain tissues. The present study characterized the pathological effects of acute inhaled toluene exposure in the lungs and brains of male Swiss-Webster mice (N = 68). Using a static vapor exposure chamber, mice (PND 28) received a single 30-min toluene administration (0, 1000, 2000, or 4000 ppm). Lung and brain tissues were extracted 24 hrs post-exposure. Histology results revealed significant changes in the morphology lung tissue (e.g., irregular cellular architecture) with the 2000 and 4000 ppm exposures expressing greater signs of pathology than control 0-ppm exposure. Markers of immune system activity (F4/80 and Ly-6G) and cellular proliferation (Ki-67) in the lung revealed no significant differences. Additionally, brain tissues were analyzed for changes of astrogliosis (GFAP) and oxidative stress (GPx). GFAP showed increased astrogliosis in the striatum with 2000 ppm toluene showing significantly higher expression than control (p < 0.05), and a marginal effect in the hippocampus. No other markers showed significant changes. The increased signs of inflammation and cellular damage suggest that exposure to a single high concentration of toluene, typical of abuse, are capable of producing pathology in both lung and brain tissue.
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Affiliation(s)
- D W Svenson
- Department of Psychology, Wayne State University, Detroit, MI, USA
| | - Cameron J Davidson
- Department of Psychology, Wayne State University, Detroit, MI, USA.,Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, USA
| | - Chitra Thakur
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
| | - Scott E Bowen
- Department of Psychology, Wayne State University, Detroit, MI, USA
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Campos-Ordoñez T, Alcalá E, Ibarra-Castañeda N, Buriticá J, González-Pérez Ó. Chronic exposure to cyclohexane induces stereotypic circling, hyperlocomotion, and anxiety-like behavior associated with atypical c-Fos expression in motor- and anxiety-related brain regions. Behav Brain Res 2021; 418:113664. [PMID: 34780858 DOI: 10.1016/j.bbr.2021.113664] [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: 06/14/2021] [Revised: 10/29/2021] [Accepted: 11/07/2021] [Indexed: 12/27/2022]
Abstract
Recreational abuse of solvents continues, despite cyclohexane (CHX) is used as a safe replacement in gasoline or adhesive formulations. Increasing evidence indicates that CHX inhalation affects brain functioning; however, scanty information is available about its effects on behavior and brain activity upon drug removal. In this study, we used CD1 adult mice to mimic an intoxication period of recreational drugs for 30 days. During the CHX exposure (~30,000 ppm), we analyzed exploratory and biphasic behaviors, stereotypic circling, and locomotion. After CHX removal (24 h or a month later), we assessed anxiety-like behaviors and quantified c-Fos cells in motor- and anxiety-related brain regions. Our findings indicate that the repeated inhalation of CHX produced steady hyperactivity and reduced ataxia, sedation, and seizures as the exposure to CHX progressed. Also, CHX decreased grooming and rearing behaviors. In the first week of CHX inhalation, a stereotypic circling behavior emerged, and locomotion increased gradually. One month after CHX withdrawal, mice showed low activity in the center zone of the open field and more buried marbles. Twenty-four hours after CHX removal, c-Fos expression was low in the dorsal striatum, ventral striatum, motor cortex, dorsomedial prefrontal cortex, basolateral amygdala, lateral hypothalamus, and ventral hippocampus. One month later, c-Fos expression remained low in the ventral striatum and lateral hypothalamus but increased in the dorsomedial prefrontal cortex and primary motor cortex. This study provides a comprehensive behavioral characterization and novel histological evidence of the CHX effects on the brain when is administered in a recreational-like mode.
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Affiliation(s)
- Tania Campos-Ordoñez
- Laboratory of Neuroscience, School of Psychology, University of Colima, Colima, Mexico; Centro de Estudios e Investigaciones en Comportamiento, University of Guadalajara, Jalisco, Mexico.
| | - Emmanuel Alcalá
- Centro de Estudios e Investigaciones en Comportamiento, University of Guadalajara, Jalisco, Mexico; Research Laboratory on Optimal Design, Devices and Advanced Materials, Department of Mathematics and Physics, ITESO, Jalisco, Mexico
| | - Nereida Ibarra-Castañeda
- Laboratory of Neuroscience, School of Psychology, University of Colima, Colima, Mexico; Medical Science PhD Program, School of Medicine, University of Colima, Colima, Mexico
| | - Jonathan Buriticá
- Centro de Estudios e Investigaciones en Comportamiento, University of Guadalajara, Jalisco, Mexico
| | - Óscar González-Pérez
- Laboratory of Neuroscience, School of Psychology, University of Colima, Colima, Mexico.
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11
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Crossin R. Exploring the link between adolescent inhalant misuse and suicidal behaviour: a behavioural toxicology perspective. Neurotoxicol Teratol 2021; 88:107038. [PMID: 34678460 DOI: 10.1016/j.ntt.2021.107038] [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: 05/26/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 10/20/2022]
Abstract
Adolescent inhalant misuse has a known association with suicidal thoughts and behaviour. This association persists even after inhalant misuse has ceased. Previous studies have hypothesised that this association may derive from socioeconomic disadvantage or vulnerability, and potentially mediated by impulsivity. This association may also be due to the central nervous system depressant effects of inhalants. This review takes a behavioural toxicology perspective, focussed particularly on the serotonergic system and the Hypothalamic-Pituitary-Adrenal (HPA) axis, as potential links between adolescent inhalant misuse and suicidal behaviour. The challenges of bridging the pre-clinical and clinical literature in this area are discussed, along with promising avenues for future research; ultimately aimed at reducing suicide risk in a vulnerable adolescent population group.
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Affiliation(s)
- Rose Crossin
- Department of Population Health, University of Otago (Christchurch), Christchurch 8140, New Zealand.
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12
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Cruz SL, Bowen SE. The last two decades on preclinical and clinical research on inhalant effects. Neurotoxicol Teratol 2021; 87:106999. [PMID: 34087382 DOI: 10.1016/j.ntt.2021.106999] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/24/2021] [Accepted: 05/18/2021] [Indexed: 12/21/2022]
Abstract
This paper reviews the scientific evidence generated in the last two decades on the effects and mechanisms of action of most commonly misused inhalants. In the first section, we define what inhalants are, how they are used, and their prevalence worldwide. The second section presents specific characteristics that define the main groups of inhalants: (a) organic solvents; (b) aerosols, gases, and volatile anesthetics; and (c) alkyl nitrites. We include a table with the molecular formula, structure, synonyms, uses, physicochemical properties and exposure limits of representative compounds within each group. The third and fourth sections review the direct acute and chronic effects of common inhalants on health and behavior with a summary of mechanisms of action, respectively. In the fifth section, we address inhalant intoxication signs and available treatment. The sixth section examines the health effects, intoxication, and treatment of nitrites. The seventh section reviews current intervention strategies. Finally, we propose a research agenda to promote the study of (a) solvents other than toluene; (b) inhalant mixtures; (c) effects in combination with other drugs of abuse; (d) age and (e) sex differences in inhalant effects; (f) the long-lasting behavioral effects of animals exposed in utero to inhalants; (g) abstinence signs and neurochemical changes after interrupting inhalant exposure; (h) brain networks involved in inhalant effects; and finally (i) strategies to promote recovery of inhalant users.
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Affiliation(s)
- Silvia L Cruz
- Department of Pharmacobiology, Center of Research and Advanced Studies (Cinvestav), Calzada de los Tenorios No. 235, Col. Granjas Coapa, México City 14330, México.
| | - Scott E Bowen
- Department of Psychology, Wayne State University, 5057 Woodward Ave., Suite 7906.1, Detroit, MI 48202, USA.
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Davidson CJ, Hannigan JH, Bowen SE. Effects of inhaled combined Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX): Toward an environmental exposure model. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 81:103518. [PMID: 33132182 DOI: 10.1016/j.etap.2020.103518] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 06/11/2023]
Abstract
Combined environmental exposures to the volatile organic compounds (VOCs) Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) pose clear risks to public health. Research into these risks is under-studied even as BTEX levels in the atmosphere are predicted to rise. This review focuses on the available literature using single- and combined-BTEX component inhaled solvent exposures in animal models, necessarily also drawing on findings from models of inhalant abuse and occupational exposures. Health effects of these exposures are discussed for multiple organ systems, but with particular attention on neurobehavioral outcomes such as locomotor activity, impulsivity, learning, and psychopharmacological responses. It is clear that animal models have significant differences in the concentrations, durations and patterns of exposure. Experimental evidence of the deleterious health and neurobehavioral consequences of exposures to the individual components of BTEX were found, but these effects were typically assessed using concentrations and exposure patterns not characteristic of environmental exposure. Future studies with animal models designed appropriately to explore combined BTEX will be necessary and advantageous to discovering health outcomes and more subtle neurobehavioral impacts of long-term environmental exposures.
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Affiliation(s)
| | - John H Hannigan
- Department of Psychology, Wayne State University, Detroit, MI, USA; Department of Obstetrics & Gynecology, Wayne State University, Detroit, MI, USA; Merrill Palmer Skillman Institute for Child & Family Development, Wayne State University, Detroit, MI, USA; Center for Urban Responses to Environmental Stressors, Wayne State University, Detroit, MI, USA
| | - Scott E Bowen
- Department of Psychology, Wayne State University, Detroit, MI, USA; Center for Urban Responses to Environmental Stressors, Wayne State University, Detroit, MI, USA.
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Apawu AK, Callan SP, Mathews TA, Bowen SE. Repeated toluene exposure leads to neuroadaptation in dopamine release mechanisms within the nucleus accumbens core. Toxicol Appl Pharmacol 2020; 408:115260. [DOI: 10.1016/j.taap.2020.115260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/17/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022]
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Environmental enrichment reduces behavioural sensitization in mice previously exposed to toluene: The role of D1 receptors. Behav Brain Res 2020; 390:112624. [DOI: 10.1016/j.bbr.2020.112624] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/11/2020] [Accepted: 03/25/2020] [Indexed: 12/20/2022]
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Minocycline prevents neuronal hyperexcitability and neuroinflammation in medial prefrontal cortex, as well as memory impairment caused by repeated toluene inhalation in adolescent rats. Toxicol Appl Pharmacol 2020; 395:114980. [PMID: 32234516 DOI: 10.1016/j.taap.2020.114980] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 03/12/2020] [Accepted: 03/27/2020] [Indexed: 02/04/2023]
Abstract
Toluene can be intentionally misused by adolescents to experience psychoactive effects. Toluene has a complex mechanism of action and broad behavioral effects, among which memory impairment is reported consistently. We have previously reported that repeated toluene inhalation (8000 ppm) increases layer 5 prelimbic pyramidal cells' excitability in the medial prefrontal cortex (mPFC) of adolescent rats. Toluene also produces reactive oxygen species (ROS), which activate glial cells. Here, we tested the hypothesis that the anti-inflammatory agent minocycline would decrease toluene's effects because it inhibits NF-κB (nuclear factor enhancer of the kappa light chains of activated B cells) and reduces pro-inflammatory cytokine and ROS production. Our results show that minocycline (50 mg/kg, ip, for 10 days) prevents the hyperexcitability of mPFC neurons observed after repeated 8000 ppm toluene exposure (30 min/day, 2×/day for 10 days). Minocycline prevents toluene-induced hyperexcitability by a mechanism that averts the loss of the slow calcium-dependent potassium current, and normalizes mPFC neurons' firing frequency. These effects are accompanied by significant decreased expression of astrocytes and activated microglia in the mPFC, reduced NLRP3 inflammasome activation and mRNA expression levels of the pro-inflammatory cytokine interleukin 1β (IL-1β), as well as increased mRNA expression of the anti-inflammatory cytokine transforming growth factor β (TGF-β). Minocycline also prevents toluene-induced memory impairment in adolescent rats in the passive avoidance task and the temporal order memory test in which the mPFC plays a central role. These results show that neuroinflammation produces several effects of repeated toluene administration at high concentrations, and minocycline can significantly prevent them.
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Soares MV, Charão MF, Jacques MT, Dos Santos ALA, Luchese C, Pinton S, Ávila DS. Airborne toluene exposure causes germline apoptosis and neuronal damage that promotes neurobehavioural changes in Caenorhabditis elegans. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 256:113406. [PMID: 31662251 DOI: 10.1016/j.envpol.2019.113406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
Toluene is a highly volatile organic solvent present in gasoline. Exposure mainly occurs by absorption via the pulmonary tract and easily reaches the central nervous system, which causes toxic effects. Toluene toxicity has been described but not well established. The present work aimed to evaluate the effects of airborne exposure to toluene, the in vivo model Caenorhabditis elegans was assessed to determine whether nematode could be used to evaluate the effects of exposure to toluene and the possible mechanisms of toxicity of the solvent. Worms at the first or fourth larval stages were exposed to toluene for 48 or 24 h, respectively, in a laboratory-developed vapor chamber at concentrations of 450, 850, 1250 and 1800 ppm. We observed increases in worm mortality and significant developmental delays that occurred in a concentration-dependent manner. An increased incidence of apoptotic events in treated germline cells was shown, which was consistent with observed reductions in reproductive capacity. In addition, toluene promoted significant behavioural changes affecting swimming movements and radial locomotion, which were associated with changes in the fluorescence intensity and morphology of GABAergic and cholinergic neurons. We conclude that toluene exposure was toxic to C. elegans, with effects produced by the induction of apoptosis and neuronal damage.
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Affiliation(s)
- Marcell Valandro Soares
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil
| | - Mariele Feiffer Charão
- Laboratório de Toxicologia Analítica, Universidade Feevale, Rua Rubem Berta, nº 200, Novo Hamburgo, CEP: 93525-090, RS, Brazil
| | - Mauricio Tavares Jacques
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil; Laboratório de Experimentação em Neuropatologia - Departamento de Bioquímica, CCB, Universidade Federal de Santa Catarina, Bloco C, Trindade, Florianópolis, SC, CEP 88040-900, Brazil
| | - Ana Laura Anibaletto Dos Santos
- Laboratório de Toxicologia Analítica, Universidade Feevale, Rua Rubem Berta, nº 200, Novo Hamburgo, CEP: 93525-090, RS, Brazil
| | - Cristiane Luchese
- Programa de Pós-Graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Universidade Federal de Pelotas, Pelotas, RS, 96010-900, Brazil
| | - Simone Pinton
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil
| | - Daiana Silva Ávila
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil.
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The Abused Inhalant Toluene Impairs Medial Prefrontal Cortex Activity and Risk/Reward Decision-Making during a Probabilistic Discounting Task. J Neurosci 2019; 39:9207-9220. [PMID: 31548237 DOI: 10.1523/jneurosci.1674-19.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/11/2019] [Accepted: 09/17/2019] [Indexed: 12/29/2022] Open
Abstract
Inhalant (e.g., toluene) misuse is linked to behavioral and cognitive deficits in humans, yet preclinical studies of the effect of inhalants on higher-order cognition are limited. We addressed this gap in the literature by examining the effect of toluene vapor exposure on risk/reward decision-making in male and female Sprague-Dawley rats using a probabilistic discounting task. In this task, rodents chose a risky/large reward or a safe/small reward, with the odds of risky reinforcement descending or ascending throughout the test session. We observed a dose-dependent, sex-independent deficit in behavioral flexibility during probabilistic discounting caused by acute toluene exposure. Rats exposed to toluene vapor during adolescence and tested as adults performed comparably to air-treated controls and were susceptible to the effects of an acute toluene challenge. These behavioral flexibility deficits observed suggests dysfunctional medial prefrontal cortex (mPFC) activity. To address this hypothesis, we virally expressed the genetically encoded calcium sensor GCaMP6f in glutamatergic mPFC neurons and monitored calcium transients in real-time using in vivo fiber photometry. mPFC activity peaked before either lever press during free-choice trials in toluene- and air-treated animals. During forced-choice trials, GCaMP6f transients shifted from pre-risky to pre-safe choice, an effect mitigated by acute toluene exposure. mPFC activity decreased during rewarded trials, with larger decreases following risky/large wins compared with safe/small wins. Toluene-treated animals also had decreased mPFC activity during rewarded trials, but there was no distinction between risky/large wins and safe/small wins. These results provide physiological evidence for mPFC-dependent behavioral deficits caused by toluene.SIGNIFICANCE STATEMENT Inhalants (e.g., toluene) are an understudied class of drugs of abuse that cause devastating behavioral and cognitive deficits in humans. Understanding the neurobiological interactions of toluene vapor using animal models is important for developing effective treatment strategies for inhalant addicts. Here we find that toluene vapor reduces behavioral flexibility in rodents making risk/reward-based decisions. The medial prefrontal cortex (mPFC) drives behavioral flexibility during this type of decision-making and we show that toluene reduces the ability of mPFC neurons to track optimal choices as reward probabilities change. Toluene also reduces these neurons' ability to distinguish between small and large rewards. A combination of these factors likely leads to the impaired performance in probabilistic discounting following acute toluene exposure.
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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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20
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Acute and Chronic Exposure of Toluene Induces Genotoxicity in Different Regions of the Brain in Normal and Allergic Mouse Models. Neurotox Res 2019; 36:669-678. [PMID: 30888611 DOI: 10.1007/s12640-019-00024-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 10/27/2022]
Abstract
Toluene is a widely used industrial organic solvent and is ubiquitous in our environment. The neurobehavioral and neurotoxic effects of toluene are well recognized; however, its genotoxicity is still under discussion. Toluene biotransformation leads to the generation of reactive oxygen species that cause oxidative stress and DNA damages. Individuals with different immunogenetic backgrounds have different sensitivities to toxic chemical exposure. Previous studies have suggested that allergic stimulation may influence the threshold for toluene sensitivity due to the modulation of neurotrophin-related genes. Therefore, we aimed to investigate toluene-induced genotoxicity in different brain regions following acute and chronic exposure in vivo and to further examine whether allergic stimulation may influence the sensitivity to toluene-induced genotoxicity. In this present study, we found that exposure of toluene induced oxidative DNA damages resulting in genotoxicity in different brain regions including cortex, cerebellum, and hippocampus using comet assay. Higher genotoxicity induced by toluene was observed in the hippocampus of control mice compared to OVA-immunized mice. These results provide evidence that toluene-induced genotoxicity may contribute to its neurotoxicity in different immunogenetic individuals.
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21
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Crossin R, Scott D, Witt KG, Duncan JR, Smith K, Lubman DI. Acute harms associated with inhalant misuse: Co-morbidities and trends relative to age and gender among ambulance attendees. Drug Alcohol Depend 2018; 190:46-53. [PMID: 29981942 DOI: 10.1016/j.drugalcdep.2018.05.026] [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: 03/23/2018] [Revised: 05/17/2018] [Accepted: 05/17/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND Inhalant misuse is the deliberate inhalation of products containing toluene to induce intoxication. Chronic harms associated with inhalant misuse are well described; including alcohol and other drug use, mental health disorders, and suicidal behaviours. However, the nature of the acute harms from inhalants and characteristics of people who experience those harms are not well understood. Therefore, this study aimed to identify the acute harms associated with inhalant misuse attendances, and to determine whether these differ by age or gender. METHODS Ambulance attendance data (Victoria, Australia) from January 2012 to June 2017 were extracted from a database of coded ambulance records. 779 ambulance attendances involving inhalant misuse were identified. Attendance characteristics were categorised by age and gender. Co-morbidities of current mental health, self-harm and suicidal behaviour were assessed, plus the involvement of alcohol and other drugs. RESULTS Overall, attendances related to the acute harms of inhalant misuse have decreased over time, although that trend has reversed from January 2015. Gender differentiated the acute harms associated with inhalant misuse. Males were older and presented with concurrent alcohol and other drug use. Females were younger and presented with concurrent suicidal ideation and self-injury. Attendances for under 15-year-olds are increasing; this age group was over-represented, predominantly female, with a strong association with self-injury. CONCLUSIONS Ambulance presentations related to inhalant misuse were associated with acute and serious harms. This study highlights that the acute treatment needs of those misusing inhalants are complex and may need to be tailored to gender and age groups.
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Affiliation(s)
- Rose Crossin
- Eastern Health Clinical School, Monash University, Box Hill, VIC, 3128, Australia; Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia; Turning Point, Eastern Health, Richmond, VIC, 3121, Australia.
| | - Debbie Scott
- Eastern Health Clinical School, Monash University, Box Hill, VIC, 3128, Australia; Turning Point, Eastern Health, Richmond, VIC, 3121, Australia.
| | - Katrina G Witt
- Eastern Health Clinical School, Monash University, Box Hill, VIC, 3128, Australia; Turning Point, Eastern Health, Richmond, VIC, 3121, Australia.
| | - Jhodie R Duncan
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.
| | - Karen Smith
- Ambulance Victoria, Doncaster, VIC, 3108, Australia; Department of Community Emergency Health and Paramedic Practice, Monash University, Frankston, VIC, 3199, Australia.
| | - Dan I Lubman
- Eastern Health Clinical School, Monash University, Box Hill, VIC, 3128, Australia; Turning Point, Eastern Health, Richmond, VIC, 3121, Australia.
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Malloul H, Bennis M, Ba-M'hamed S. Positive reinforcement and c-Fos expression following abuse-like thinner inhalation in mice: Behavioural and immunohistochemical assessment. Eur J Neurosci 2018; 48:2182-2198. [PMID: 30070747 DOI: 10.1111/ejn.14095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 07/01/2018] [Accepted: 07/18/2018] [Indexed: 01/11/2023]
Abstract
Thinners are organic solvents widely used in industrial applications, but they have also been subject to abuse by inhalation for their psychoactive and rewarding properties. In spite of the prevalence of inhalant abuse, the addictive potential and pathways mediating their reinforcing effects are not yet fully understood and thus still subject of further investigations. Here, we assessed in mice the locomotor activity and the ability of paint thinner to reinforce the conditioning in the place preference paradigm following acute (1 day), subchronic (6 weeks) and chronic (12 weeks) exposures to 300 and 600 ppm of thinner vapor. While locomotor activity was unaffected by the different thinner treatments, a positive conditioned place preference to inhaled thinner was found upon subchronic and chronic exposures. To investigate the activated brain structures underlying such behavioural changes, we analyzed the distribution of c-Fos immunoreactivity, a marker for neuronal activation, following acute and repeated exposures to 600 ppm of thinner. Notably, thinner exposure increased the number of c-Fos immunoreactive neurons with increasing duration of exposure in the majority of structures examined; including those typically involved in the processing of rewarding or emotionally stimuli (e.g., ventral tegmental area, core and shell of nucleus accumbens, amygdala, bed nucleus of the stria terminalis, and cingulate cortex), and olfactory stimuli (e.g., piriform cortex and olfactory tubercle). Moreover, prolonged, but not acute thinner inhalation significantly increased c-Fos immunoreactivity in all hippocampal subregions. Taken together, the expanded distribution of thinner-induced c-Fos expression may underlie the observed positive reinforcement upon long-term thinner inhalation.
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Affiliation(s)
- Hanaa Malloul
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Mohammed Bennis
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Saadia Ba-M'hamed
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
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Repeated toluene exposure increases the excitability of layer 5 pyramidal neurons in the prefrontal cortex of adolescent rats. Neurotoxicol Teratol 2018; 68:27-35. [DOI: 10.1016/j.ntt.2018.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/26/2018] [Accepted: 04/27/2018] [Indexed: 12/11/2022]
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Delfino-Pereira P, Bertti-Dutra P, de Lima Umeoka EH, de Oliveira JAC, Santos VR, Fernandes A, Marroni SS, Del Vecchio F, Garcia-Cairasco N. Intense olfactory stimulation blocks seizures in an experimental model of epilepsy. Epilepsy Behav 2018; 79:213-224. [PMID: 29346088 DOI: 10.1016/j.yebeh.2017.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022]
Abstract
There are reports of patients whose epileptic seizures are prevented by means of olfactory stimulation. Similar findings were described in animal models of epilepsy, such as the electrical kindling of amygdala, where olfactory stimulation with toluene (TOL) suppressed seizures in most rats, even when the stimuli were 20% above the threshold to evoke seizures in already kindled animals. The Wistar Audiogenic Rat (WAR) strain is a model of tonic-clonic seizures induced by acute acoustic stimulation, although it also expresses limbic seizures when repeated acoustic stimulation occurs - a process known as audiogenic kindling (AK). The aim of this study was to evaluate whether or not the olfactory stimulation with TOL would interfere on the behavioral expression of brainstem (acute) and limbic (chronic) seizures in the WAR strain. For this, animals were exposed to TOL or saline (SAL) and subsequently exposed to acoustic stimulation in two conditions that generated: I) acute audiogenic seizures (only one acoustic stimulus, without previous seizure experience before of the odor test) and II) after AK (20 acoustic stimuli [2 daily] before of the protocol test). We observed a decrease in the seizure severity index of animals exposed only to TOL in both conditions, with TOL presented 20s before the acoustic stimulation in both protocols. These findings were confirmed by behavioral sequential analysis (neuroethology), which clearly indicated an exacerbation of clusters of specific behaviors such as exploration and grooming (self-cleaning), as well as significant decrease in the expression of brainstem and limbic seizures in response to TOL. Thus, these data demonstrate that TOL, a strong olfactory stimulus, has anticonvulsant properties, detected by the decrease of acute and AK seizures in WARs.
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Affiliation(s)
- Polianna Delfino-Pereira
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil
| | - Poliana Bertti-Dutra
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Eduardo Henrique de Lima Umeoka
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - José Antônio Cortes de Oliveira
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Victor Rodrigues Santos
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Artur Fernandes
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil; Genetics Department, Ribeirão Preto School of Medicine, University of São Paulo, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Simone Saldanha Marroni
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Flávio Del Vecchio
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Norberto Garcia-Cairasco
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil.
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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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Wang B, Yang J, Chen J, Kang Y, Yang LH, Liu J, Zhang WS. An Etomidate Analogue With Less Adrenocortical Suppression, Stable Hemodynamics, and Improved Behavioral Recovery in Rats. Anesth Analg 2017; 125:442-450. [PMID: 28514325 DOI: 10.1213/ane.0000000000002063] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND ET-26 hydrochloride (ET-26HCl) is a novel etomidate analogue designed to alleviate the adrenocortical suppression caused by etomidate while retaining the rapid sedative-hypnotic onset and stable hemodynamic features of etomidate. This study compared the anesthetic effect, hemodynamic stability, and recovery profiles of ET-26HCl, etomidate, and the sedative-hypnotic drug propofol in rats. METHODS The metabolic half-life of ET-26HCl was determined in vitro using high performance liquid chromatography analysis of samples of rat plasma and liver homogenates taken from 3 animals. Hypnotic median effective doses (HD50) of ET-26HCl, etomidate, and propofol were determined by up-and-down methods. Anesthesia effect and mean arterial pressure were estimated using equivalent intravenous (IV) doses of propofol, etomidate, and ET-26HCl in the rats. Serum concentrations of corticosterone were analyzed by enzyme-linked immunosorbent assay. The ability of rats to recover from the sedative-hypnotic effects of the drugs was evaluated using open field and Morris water maze tests at equipotent doses of propofol, etomidate, ET-26HCl, and normal saline. RESULTS The metabolic half-life of ET-26HCl was 81 ± 6 minutes in rat plasma and 126 ± 12 minutes in incubation liver homogenate (mean ± standard deviation), respectively. In vivo experiments showed that the potency of ET-26HCl to cause a loss of righting reflex in rats was 3 times lower than that of etomidate in the rats. IV propofol caused a greater decrease in mean arterial pressure relative to the baseline (-27.9 mm Hg) than did ET-26HCl (-10.7 mm Hg) and etomidate (-19.4 mm Hg) at equipotent doses. Serum corticosterone levels after drug administration were significantly higher in the ET-26HCl group than in the etomidate group at equivalent doses when measured 15 (P < .001), 30 (P < .001), and 60 (P = .002) minutes after stimulation with adrenocorticotropic hormone (ACTH1-24). Recovery of spatial orientation from anesthesia induced by an IV bolus injection was faster with ET-26HCl than with propofol, but recovery of spontaneous activity was slower. CONCLUSIONS ET-26HCl has anesthetic potency and hemodynamic stability similar to etomidate, but it caused less adrenocortical hormone synthesis suppression than etomidate and faster spatial orientation recovery from anesthesia than propofol, which was similar to etomidate.
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Affiliation(s)
- Bin Wang
- From the *Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, The People's Republic of China; †Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, The People's Republic of China; and ‡Laboratory Department Guizhou Provincial Corps Hospital of PAPF, Guiyang, Guizhou, China
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Montes S, Solís-Guillén RDC, García-Jácome D, Páez-Martínez N. Environmental enrichment reverses memory impairment induced by toluene in mice. Neurotoxicol Teratol 2017; 61:7-16. [DOI: 10.1016/j.ntt.2017.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 04/12/2017] [Accepted: 04/18/2017] [Indexed: 01/02/2023]
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Callan SP, Hannigan JH, Bowen SE. Prenatal toluene exposure impairs performance in the Morris Water Maze in adolescent rats. Neuroscience 2017; 342:180-187. [PMID: 26318334 PMCID: PMC4769973 DOI: 10.1016/j.neuroscience.2015.08.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 08/11/2015] [Accepted: 08/21/2015] [Indexed: 11/17/2022]
Abstract
Volatile organic solvent abuse continues to be a worldwide health problem, including the neurobehavioral teratogenic sequelae of toluene abuse during pregnancy. Although abuse levels of prenatal toluene exposure can lead to a Fetal Solvent Syndrome, there is little research examining these effects on memory. Consumption of toluene can have detrimental effects on the developing hippocampus which could lead to specific spatial learning and memory deficits. This study used a rat model to determine how prenatal exposure to abuse levels of toluene would affect performance in a spatial learning and memory task, the Morris Water Maze (MWM). Pregnant Sprague-Dawley rats were exposed to 0, 8000 or 12,000ppm (ppm) of toluene for 15min twice daily from gestation day 8 (GD8) through GD20. Male and female offspring (N=104) were observed in the MWM for 5days beginning on postnatal day (PN) 28 and again on PN44. While prenatal toluene-exposed animals did not differ in initial acquisition in the MWM, rats prenatally exposed to 12,000ppm toluene displayed performance deficits during a probe trial and in reversal learning on PN44. Overall, this study indicates that prenatal exposure to repeated inhaled abuse patterns of high concentrations of toluene can impair spatial memory function that persists into adolescence.
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Affiliation(s)
- S P Callan
- Department of Psychology, Wayne State University, Detroit, MI, United States; Behavioral Pharmacology and Toxicology Laboratory, Wayne State University, Detroit, MI, United States
| | - J H Hannigan
- Department of Psychology, Wayne State University, Detroit, MI, United States; Department of Obstetrics & Gynecology, Wayne State University, Detroit, MI, United States; Merrill Palmer Skillman Institute for Child and Family Development, Wayne State University, Detroit, MI, United States
| | - S E Bowen
- Department of Psychology, Wayne State University, Detroit, MI, United States; Behavioral Pharmacology and Toxicology Laboratory, Wayne State University, Detroit, MI, United States.
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Cruz SL, Gauthereau-Torres MY, Rivera-García MT. Structure-activity relationship for the anticonvulsant effects of organic solvents. Neurotoxicology 2016; 57:121-127. [DOI: 10.1016/j.neuro.2016.09.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 09/19/2016] [Accepted: 09/19/2016] [Indexed: 02/01/2023]
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Li Y, Song Z, Ding Y, Xin Y, Wu T, Su T, He R, Tai F, Lian Z. Effects of formaldehyde exposure on anxiety-like and depression-like behavior, cognition, central levels of glucocorticoid receptor and tyrosine hydroxylase in mice. CHEMOSPHERE 2016; 144:2004-2012. [PMID: 26551198 DOI: 10.1016/j.chemosphere.2015.10.102] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 10/21/2015] [Accepted: 10/25/2015] [Indexed: 06/05/2023]
Abstract
Formaldehyde exposure is toxic to the brains of mammals, but the mechanism remains unclear. We investigated the effects of inhaled formaldehyde on anxiety, depression, cognitive capacity and central levels of glucocorticoid receptor and tyrosine hydroxylase in mice. After exposure to 0, 1 or 2 ppm gaseous formaldehyde for one week, we measured anxiety-like behavior using open field and elevated plus-maze tests, depression-like behavior using a forced swimming test, learning and memory using novel object recognition tests, levels of glucocorticoid receptors in the hippocampus and tyrosine hydroxylase in the Arc, MPOA, ZI and VTA using immuhistochemistry. We found that inhalation of 1 ppm formaldehyde reduced levels of anxiety-like behavior. Inhalation of 2 ppm formaldehyde reduced body weight, but increased levels of depression-like behavior, impaired novel object recognition, and lowered the numbers of glucocorticoid receptor immonureactive neurons in the hippocampus and tyrosine hydroxylase immonureactive neurons in the ventral tegmental area and the zona incerta, medial preoptic area. Different concentrations of gaseous formaldehyde result in different effects on anxiety, depression-like behavior and cognition ability which may be associated with alterations in hippocampal glucocorticoid receptors and brain tyrosine hydroxylase levels.
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Affiliation(s)
- Yani Li
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China; College of Energy and Environmental Engineering, Yan'an University, Yan'an, Shaanxi 716000, China
| | - Zhuoyi Song
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China
| | - Yujuan Ding
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China
| | - Ye Xin
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China
| | - Tong Wu
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China
| | - Tao Su
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongqiao He
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Fadao Tai
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China.
| | - Zhenmin Lian
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China
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Levicheva NA, Titkova AM. FEATURES OF LIMBIC-NEOCORTICAL AND MONOAMINERGIC CORRELATIONS IN THE DEVELOPMENT OF WITHDRAWAL SYNDROME OF INHALATIONS OF VAPORS OF ORGANIC SOLVENT «646» IN RATS. FIZIOLOHICHNYI ZHURNAL (KIEV, UKRAINE : 1994) 2016; 62:60-65. [PMID: 29569887 DOI: 10.15407/fz62.03.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The aim of the work was to study the limbic-neocortical and monoaminergic features of the development of withdrawal syndrome of volatile organic compounds (VOC) inhalations in rats. The study was carried out in 30 three months old male rats with dependence on inhalations of organic solvent “646” which contains up to 50 % mix of toluene and acetone. It has been shown that the withdrawal syndrome of inhalant is characterized by increased excitability and behavioral manifestations of equivalents of convulsive reactions such as oral hyperkinesis, head shaking and changes in the frequencyamplitude spectrum of the biopotentials in structures of the brain limbic-neocortical system with the initiation in the medial olfactory region and hippocampus. At the hypothalamus level, withdrawal of VOC inhalations produces the depleting impact on the catecholaminergic structures with a stronger effect in neuronal endings with adrenaline as neurotransmitter. Withdrawal syndrome evokes a significant decrease in dopamine content by 61 %, noradrenaline by 77 % and adrenaline by 92 % in the hypothalamus and increase in serotonin concentration in blood serum by 16 % in rats with initial preference to inhalations of organic solvent “646”. In rats with the absence of initial preference to inhalations of organic solvent “646” a decrease in adrenaline level in the hypothalamus by 77 % was detected.
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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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Apawu AK, Mathews TA, Bowen SE. Striatal dopamine dynamics in mice following acute and repeated toluene exposure. Psychopharmacology (Berl) 2015; 232:173-84. [PMID: 24994552 DOI: 10.1007/s00213-014-3651-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 06/02/2014] [Indexed: 02/02/2023]
Abstract
RATIONALE The abused inhalant toluene has potent behavioral effects, but only recently has progress been made in understanding the neurochemical actions that mediate the action of toluene in the brain. Available evidence suggests that toluene inhalation alters dopamine (DA) neurotransmission, but toluene's mechanism of action is unknown. OBJECTIVE The present study evaluated the effect of acute and repeated toluene inhalation (0, 2,000, or 4,000 ppm) on locomotor activity as well as striatal DA release and uptake using slice fast-scan cyclic voltammetry. RESULTS Acutely, 2,000 and 4,000 ppm toluene increased locomotor activity, while neurochemically only 4,000 ppm toluene potentiated electrically evoked DA release across the caudate-putamen and the nucleus accumbens. Repeated administration of toluene resulted in sensitization to toluene's locomotor activity effects. Brain slices obtained from mice repeatedly exposed to toluene demonstrated no difference in stimulated DA release in the caudate-putamen as compared to control animals. Repeated exposure to 2,000 and 4,000 ppm toluene caused a concentration-dependent decrease of 25-50 % in evoked DA release in the nucleus accumbens core and shell relative to air-exposed mice. CONCLUSIONS These voltammetric neurochemical findings following repeated toluene exposure suggest that there may be a compensatory downregulation of the DA system. Acute or repeated toluene exposure had no effect on the DA uptake kinetics. Taken together, these results demonstrate that acute toluene inhalation potentiates DA release, while repeated toluene exposure attenuates DA release in the nucleus accumbens only.
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Affiliation(s)
- Aaron K Apawu
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI, 48202, USA
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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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Cruz SL, Rivera-García MT, Woodward JJ. Review of toluene action: clinical evidence, animal studies and molecular targets. ACTA ACUST UNITED AC 2014; 3. [PMID: 25360325 DOI: 10.4303/jdar/235840] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
It has long been known that individuals will engage in voluntary inhalation of volatile solvents for their rewarding effects. However, research into the neurobiology of these agents has lagged behind that of more commonly used drugs of abuse such as psychostimulants, alcohol and nicotine. This imbalance has begun to shift in recent years as the serious effects of abused inhalants, especially among children and adolescents, on brain function and behavior have become appreciated and scientifically documented. In this review, we discuss the physicochemical and pharmacological properties of toluene, a representative member of a large class of organic solvents commonly used as inhalants. This is followed by a brief summary of the clinical and pre-clinical evidence showing that toluene and related solvents produce significant effects on brain structures and processes involved in the rewarding aspects of drugs. This is highlighted by tables highlighting toluene's effect on behaviors (reward, motor effects, learning, etc.) and cellular proteins (e.g. voltage and ligand-gated ion channels) closely associated the actions of abused substances. These sections demonstrate not only the significant progress that has been made in understanding the neurobiological basis for solvent abuse but also reveal the challenges that remain in developing a coherent understanding of this often overlooked class of drugs of abuse.
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Affiliation(s)
- Silvia L Cruz
- Departamento de Farmacobiología, Cinvestav, México, D.F., University of South Carolina, Charleston, SC
| | | | - John J Woodward
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC
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Beckley JT, Woodward JJ. Volatile solvents as drugs of abuse: focus on the cortico-mesolimbic circuitry. Neuropsychopharmacology 2013; 38:2555-67. [PMID: 23954847 PMCID: PMC3828545 DOI: 10.1038/npp.2013.206] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/12/2013] [Accepted: 08/13/2013] [Indexed: 12/15/2022]
Abstract
Volatile solvents such as those found in fuels, paints, and thinners are found throughout the world and are used in a variety of industrial applications. However, these compounds are also often intentionally inhaled at high concentrations to produce intoxication. While solvent use has been recognized as a potential drug problem for many years, research on the sites and mechanisms of action of these compounds lags behind that of other drugs of abuse. In this review, we first discuss the epidemiology of voluntary solvent use throughout the world and then consider what is known about their basic pharmacology and how this may explain their use as drugs of abuse. We next present data from preclinical and clinical studies indicating that these substances induce common addiction sequelae such as dependence, withdrawal, and cognitive impairments. We describe how toluene, the most commonly studied psychoactive volatile solvent, alters synaptic transmission in key brain circuits such as the mesolimbic dopamine system and medial prefrontal cortex (mPFC) that are thought to underlie addiction pathology. Finally, we make the case that activity in mPFC circuits is a critical regulator of the mesolimbic dopamine system's ability to respond to volatile solvents like toluene. Overall, this review provides evidence that volatile solvents have high abuse liability because of their selective effects on critical nodes of the addiction neurocircuitry, and underscores the need for more research into how these compounds induce adaptations in neural circuits that underlie addiction pathology.
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Affiliation(s)
- Jacob T Beckley
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA,Center for Drug and Alcohol Programs, Department of Psychiatry/Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - John J Woodward
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA,Center for Drug and Alcohol Programs, Department of Psychiatry/Neurosciences, Medical University of South Carolina, Charleston, SC, USA,Department of Neurosciences, Medical University of South Carolina, IOP 4 North, 67 President Street, MSC 861, Charleston, SC 29425, USA, Tel: +(843) 792 5225, Fax: +(843) 792 7353, E-mail:
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Environmental enrichment increases doublecortin-associated new neurons and decreases neuronal death without modifying anxiety-like behavior in mice chronically exposed to toluene. Behav Brain Res 2013; 256:432-40. [DOI: 10.1016/j.bbr.2013.09.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 08/28/2013] [Accepted: 09/01/2013] [Indexed: 11/20/2022]
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Tomaszycki ML, Aulerich KE, Bowen SE. Repeated toluene exposure increases c-Fos in catecholaminergic cells of the nucleus accumbens shell. Neurotoxicol Teratol 2013; 40:28-34. [PMID: 24036183 DOI: 10.1016/j.ntt.2013.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/03/2013] [Accepted: 09/05/2013] [Indexed: 11/26/2022]
Abstract
Toluene is a frequently abused solvent. Previous studies have suggested that toluene acts like other drugs of abuse, specifically on the dopaminergic system in the nucleus accumbens (NAc) and ventral tegmental area (VTA) of the mesolimbic pathway. Although changes in dopamine (DA) levels and c-Fos have been observed in both acute and repeated exposure paradigms, the extent to which c-Fos is localized to catecholaminergic cells is unknown. The present study tested the effects of repeated toluene exposure (1000-4000ppm) on locomotor activity and cells containing c-Fos, tyrosine hydroxylase (TH), or both in the core and shell of the NAc, as well as the anterior and posterior VTA. We focused our study on adolescents, since adolescence is a time of great neural change and a time when individuals tend to be more susceptible to drug abuse. In early tests, toluene dose-dependently increased locomotor activity. Repeated exposure to the highest concentration of toluene resulted in sensitization to toluene's effects on locomotor activity. Although the number of cells immunopositive for c-Fos or TH did not significantly differ across groups, cells immunopositive for TH+c-Fos were higher in the NAc shell of animals exposed to 4000ppm than in animals exposed to air (control) or 1000ppm. Taken together, these findings demonstrate that repeated high dose toluene exposure increases locomotor activity as well as activation of catecholaminergic cells in the shell of the NAc.
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Affiliation(s)
- Michelle L Tomaszycki
- Department of Psychology, Wayne State University, Detroit, MI, United States; The Behavioral Neuroscience of Social Relationships Laboratory, Wayne State University, Detroit, MI, United States.
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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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Adolescent toluene inhalation in rats affects white matter maturation with the potential for recovery following abstinence. PLoS One 2012; 7:e44790. [PMID: 23028622 PMCID: PMC3445546 DOI: 10.1371/journal.pone.0044790] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 08/13/2012] [Indexed: 12/16/2022] Open
Abstract
Inhalant misuse is common during adolescence, with ongoing chronic misuse associated with neurobiological and cognitive abnormalities. While human imaging studies consistently report white matter abnormalities among long-term inhalant users, longitudinal studies have been lacking with limited data available regarding the progressive nature of such abnormalities, including the potential for recovery following periods of sustained abstinence. We exposed adolescent male Wistar rats (postnatal day 27) to chronic intermittent inhaled toluene (3,000 ppm) for 1 hour/day, 3 times/week for 8 weeks to model abuse patterns observed in adolescent and young adult human users. This dosing regimen resulted in a significant retardation in weight gain during the exposure period (p<0.05). In parallel, we performed longitudinal magnetic resonance imaging (T₂-weighted) and diffusion tensor imaging prior to exposure, and after 4 and 8 weeks, to examine the integrity of white matter tracts, including the anterior commissure and corpus callosum. We also conducted imaging after 8 weeks of abstinence to assess for potential recovery. Chronic intermittent toluene exposure during adolescence and early adulthood resulted in white matter abnormalities, including a decrease in axial (p<0.05) and radial (p<0.05) diffusivity. These abnormalities appeared region-specific, occurring in the anterior commissure but not the corpus callosum and were not present until after at least 4 weeks of exposure. Toluene-induced effects on both body weight and white matter parameters recovered following abstinence. Behaviourally, we observed a progressive decrease in rearing activity following toluene exposure but no difference in motor function, suggesting cognitive function may be more sensitive to the effects of toluene. Furthermore, deficits in rearing were present by 4 weeks suggesting that toluene may affect behaviour prior to detectable white matter abnormalities. Consequently, exposure to inhalants that contain toluene during adolescence and early adulthood appear to differentially affect white matter maturation and behavioural outcomes, although recovery can occur following abstinence.
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Conti AC, Lowing JL, Susick LL, Bowen SE. Investigation of calcium-stimulated adenylyl cyclases 1 and 8 on toluene and ethanol neurobehavioral actions. Neurotoxicol Teratol 2012; 34:481-8. [PMID: 22789433 DOI: 10.1016/j.ntt.2012.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 06/25/2012] [Accepted: 06/29/2012] [Indexed: 11/26/2022]
Abstract
The abused inhalant toluene has potent behavioral effects, but only recently has progress been made in understanding the molecular pathways that mediate the action of toluene in the brain. Toluene and ethanol induce similar behavioral effects and share some targets including NMDA and GABA receptors. In studies examining neuronal actions of ethanol, mice lacking the calcium-stimulated adenylyl cyclases (ACs), AC1 and AC8 (DKO), show increased sedation durations and impaired protein kinase A (PKA) phosphorylation following acute ethanol treatment. Therefore, using DKO mice, we compared the neurobehavioral responses following toluene exposure to that of ethanol exposure to determine if these abused substances share molecular mechanisms of action. In the present study, acute sensitivity to toluene- or ethanol-induced changes in locomotor activity was evaluated in DKO and wild type (WT) mice. Mice were exposed to toluene vapor (0, 500, 1000, 2000, 6000, or 8000ppm) for 30min in static exposure chambers equipped with activity monitors. Both WT and DKO mice demonstrated increased ambulatory distance during exposure to a 2000-ppm concentration of toluene compared to respective air-exposed (0ppm) controls. Significant increases in locomotor activity were also observed during an air-only recovery period following toluene exposure in WT and DKO mice that had been exposed to 2000ppm of toluene compared to respective air controls. Sedative effects of toluene were equivalent in WT and DKO mice, both during exposure and afterwards during recovery. Although no significant differences in locomotor activity were detected in DKO compared to WT mice at individual doses tested, a significant main effect of toluene was achieved, with DKO mice demonstrating a generalized reduction in locomotor activity during the post-toluene recovery period compared to WT mice (when analyzing all doses collectively). For comparison to toluene, additional WT and DKO mice were treated with 1.0 or 2.0g/kg ethanol (i.p.) and monitored for locomotor activation. In WT mice, both doses of ethanol increased distance traveled compared to saline controls. Conversely, DKO mice demonstrated no increase in locomotor activation at 1.0g/kg, with significantly reduced distances traveled at both doses compared to ethanol-treated WT mice. These behavioral activity results suggest that acute effects of ethanol and toluene are distinct in the mechanisms by which they induce acute sedating effects with respect to AC1 and AC8 activity, but may be similar in the mechanisms subserving locomotor stimulation.
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Affiliation(s)
- Alana C Conti
- John D. Dingell VA Medical Center, Detroit, MI 48201, USA.
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Huerta-Rivas A, López-Rubalcava C, Sánchez-Serrano SL, Valdez-Tapia M, Lamas M, Cruz SL. Toluene impairs learning and memory, has antinociceptive effects, and modifies histone acetylation in the dentate gyrus of adolescent and adult rats. Pharmacol Biochem Behav 2012; 102:48-57. [DOI: 10.1016/j.pbb.2012.03.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 03/14/2012] [Accepted: 03/24/2012] [Indexed: 12/18/2022]
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Zhvania MG, Chilachava LR, Japaridze NJ, Gelazonia LK, Lordkipanidze TG. Immediate and persisting effect of toluene chronic exposure on hippocampal cell loss in adolescent and adult rats. Brain Res Bull 2012; 87:187-92. [DOI: 10.1016/j.brainresbull.2011.10.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 10/26/2011] [Accepted: 10/30/2011] [Indexed: 01/13/2023]
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Bosse KE, Maina FK, Birbeck JA, France MM, Roberts JJP, Colombo ML, Mathews TA. Aberrant striatal dopamine transmitter dynamics in brain-derived neurotrophic factor-deficient mice. J Neurochem 2011; 120:385-95. [PMID: 21988371 DOI: 10.1111/j.1471-4159.2011.07531.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) modulates the synaptic transmission of several monoaminergic neuronal systems, including forebrain dopamine-containing neurons. Recent evidence shows a strong correlation between neuropsychiatric disorders and BDNF hypofunction. The aim of the present study was to characterize the effect of low endogenous levels of BDNF on dopamine system function in the caudate-putamen using heterozygous BDNF (BDNF(+/-) ) mice. Apparent extracellular dopamine levels in the caudate-putamen, determined by quantitative microdialysis, were significantly elevated in BDNF(+/-) mice compared with wildtype controls (12 vs. 5 nM, respectively). BDNF(+/-) mice also had a potentiated increase in dopamine levels following potassium (120 mM)-stimulation (10-fold) relative to wildtype controls (6-fold). Slice fast-scan cyclic voltammetry revealed that BDNF(+/-) mice had reductions in both electrically evoked dopamine release and dopamine uptake rates in the caudate-putamen. Superfusion of BDNF led to partial recovery of the electrically stimulated dopamine release response in BDNF(+/-) mice. Conversely, tissue accumulation of L-3,4-dihydroxyphenylalanine, extracellular levels of dopamine metabolites, and spontaneous locomotor activity were unaltered. Together, this study indicates that endogenous BDNF influences dopamine system homeostasis by regulating the release and uptake dynamics of pre-synaptic dopamine transmission.
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Affiliation(s)
- Kelly E Bosse
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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Binge toluene exposure alters glutamate, glutamine and GABA in the adolescent rat brain as measured by proton magnetic resonance spectroscopy. Drug Alcohol Depend 2011; 115:101-6. [PMID: 21126832 PMCID: PMC3071441 DOI: 10.1016/j.drugalcdep.2010.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 09/07/2010] [Accepted: 11/01/2010] [Indexed: 12/23/2022]
Abstract
Despite the high incidence of toluene abuse in adolescents, little is known regarding the effect of binge exposure on neurochemical profiles during this developmental stage. In the current study, the effects of binge toluene exposure during adolescence on neurotransmitter levels were determined using high-resolution proton magnetic resonance spectroscopy ex vivo at 11.7T. Adolescent male Sprague-Dawley rats were exposed to toluene (0, 8000, or 12,000 ppm) for 15 min twice daily from postnatal day 28 (P28) through P34 and then euthanized either 1 or 7 days later (on P35 or P42) to assess glutamate (GLU), glutamine, and GABA levels in intact tissue punches from the medial prefrontal cortex (mPFC), anterior striatum and hippocampus. In the mPFC, toluene reduced GLU 1 day after exposure, with no effect on GABA, while after 7 days, GLU was no longer affected but there was an increase in GABA levels. In the hippocampus, neither GABA nor GLU was altered 1 day after exposure, whereas 7 days after exposure, increases were observed in GABA and GLU. Striatal GLU and GABA levels measured after either 1 or 7 days were not altered after toluene exposure. These findings show that 1 week of binge toluene inhalation selectively alters these neurotransmitters in the mPFC and hippocampus in adolescent rats, and that some of these effects endure at least 1 week after the exposure. The results suggest that age-dependent, differential neurochemical responses to toluene may contribute to the unique behavioral patterns associated with drug abuse among older children and young teens.
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