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El-Cheikh Mohamad A, Möhrle D, Haddad FL, Rose A, Allman BL, Schmid S. Assessing the Cntnap2 knockout rat prepulse inhibition deficit through prepulse scaling of the baseline startle response curve. Transl Psychiatry 2023; 13:321. [PMID: 37852987 PMCID: PMC10584930 DOI: 10.1038/s41398-023-02629-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/27/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023] Open
Abstract
Many neurodevelopmental disorders, including autism spectrum disorder (ASD), are associated with changes in sensory processing and sensorimotor gating. The acoustic startle response and prepulse inhibition (PPI) of startle are widely used translational measures for assessing sensory processing and sensorimotor gating, respectively. The Cntnap2 knockout (KO) rat has proven to be a valid model for ASD, displaying core symptoms, including sensory processing perturbations. Here, we used a novel method to assess startle and PPI in Cntnap2 KO rats that allows for the identification of separate scaling components: startle scaling, which is a change in startle amplitude to a given sound, and sound scaling, which reflects a change in sound processing. Cntnap2 KO rats show increased startle due to both an increased overall response (startle scaling) and a left shift of the sound/response curve (sound scaling). In the presence of a prepulse, wildtype rats show a reduction of startle due to both startle scaling and sound scaling, whereas Cntnap2 KO rats show normal startle scaling, but disrupted sound scaling, resulting in the reported PPI deficit. These results validate that startle and sound scaling by a prepulse are indeed two independent processes, with only the latter being impaired in Cntnap2 KO rats. As startle scaling is likely related to motor output and sound scaling to sound processing, this novel approach reveals additional information on the possible cause of PPI disruptions in preclinical models.
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Affiliation(s)
- Alaa El-Cheikh Mohamad
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Dorit Möhrle
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Faraj L Haddad
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Anton Rose
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Brian L Allman
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Susanne Schmid
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.
- Department of Psychology, University of Western Ontario, London, ON, Canada.
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Wolfrum C, Peleg-Raibstein D. Maternal overnutrition leads to cognitive and neurochemical abnormalities in C57BL/6 mice. Nutr Neurosci 2018; 22:688-699. [DOI: 10.1080/1028415x.2018.1432096] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Christian Wolfrum
- Laboratory of Translational Nutrition Biology, ETH Zurich, Schwerzenbach, Switzerland
| | - Daria Peleg-Raibstein
- Laboratory of Translational Nutrition Biology, ETH Zurich, Schwerzenbach, Switzerland
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Morales-Muñoz I, Martínez-Gras I, Ponce G, de la Cruz J, Lora D, Rodríguez-Jiménez R, Jurado-Barba R, Navarrete F, García-Gutiérrez MS, Manzanares J, Rubio G. Psychological symptomatology and impaired prepulse inhibition of the startle reflex are associated with cannabis-induced psychosis. J Psychopharmacol 2017. [PMID: 28648138 DOI: 10.1177/0269881117711920] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Cannabis-induced psychotic disorder (CIPD) is a psychiatric disorder induced by cannabis consumption. The psychological and psychophysiological features of this disorder are still unknown. We aimed to examine the psychological, personality and psychophysiological features of patients with CIPD. This study is an analytical extension of our previously published data, which previously found prepulse inhibition (PPI) deficits in the CIPD group used in this current paper. METHODS We used a sample of 45 patients with CIPD. After 9 months of follow up, these patients were assessed with a Symptom Checklist-90-R (SCL-90-R) questionnaire of psychopathology, with the Eysenck Personality Questionnaire, and with a psychophysiological paradigm of inhibition of the startle reflex (PPI). These results were compared with a group of patients with schizophrenia and cannabis abuse (SCHZ) ( n = 54); patients with cannabis dependence (CD) ( n = 21); and healthy controls ( n = 50). RESULTS CIPD patients obtained significant higher scores in the SCL-90-R subscale of neuroticism. These patients showed PPI percentages similar to SCHZ patients within early attentional levels (30 ms). The variables with greater correlation, and that appeared in the CIPD group were interpersonal sensitivity, depression and phobia. CONCLUSIONS Neurotic symptomatology and difficulties in inhibition of the startle reflex might be risk factors for developing CIPD.
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Affiliation(s)
- Isabel Morales-Muñoz
- 1 Department of Health, National Institute for Health and Welfare (THL), Helsinki, Finland.,2 Research Institute 12-i, Madrid, Spain
| | - Isabel Martínez-Gras
- 2 Research Institute 12-i, Madrid, Spain.,3 Hospital Universitario 12 de Octubre, Madrid, Spain.,4 Department of Psychiatry, Complutense University of Madrid, Madrid, Spain.,5 Red temática de Investigación cooperativa en salud (RETIS-Trastornos adictivos), Instituto Carlos III, MICINN and FEDER, Madrid, Spain
| | - Guillermo Ponce
- 2 Research Institute 12-i, Madrid, Spain.,3 Hospital Universitario 12 de Octubre, Madrid, Spain.,4 Department of Psychiatry, Complutense University of Madrid, Madrid, Spain.,5 Red temática de Investigación cooperativa en salud (RETIS-Trastornos adictivos), Instituto Carlos III, MICINN and FEDER, Madrid, Spain
| | - Javier de la Cruz
- 2 Research Institute 12-i, Madrid, Spain.,3 Hospital Universitario 12 de Octubre, Madrid, Spain
| | - David Lora
- 6 Clinical Research Unit (i+12), Hospital Universitario 12 de Octubre, Madrid, Spain.,7 CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Roberto Rodríguez-Jiménez
- 2 Research Institute 12-i, Madrid, Spain.,3 Hospital Universitario 12 de Octubre, Madrid, Spain.,4 Department of Psychiatry, Complutense University of Madrid, Madrid, Spain.,8 Biomedical Research Center Network for Mental Health (CIBERSAM), Madrid, Spain
| | - Rosa Jurado-Barba
- 2 Research Institute 12-i, Madrid, Spain.,3 Hospital Universitario 12 de Octubre, Madrid, Spain.,8 Biomedical Research Center Network for Mental Health (CIBERSAM), Madrid, Spain
| | - Francisco Navarrete
- 5 Red temática de Investigación cooperativa en salud (RETIS-Trastornos adictivos), Instituto Carlos III, MICINN and FEDER, Madrid, Spain.,9 Institute for Neurosciences, Miguel Hernández University-CSIC, Alicante, Spain
| | - María Salud García-Gutiérrez
- 5 Red temática de Investigación cooperativa en salud (RETIS-Trastornos adictivos), Instituto Carlos III, MICINN and FEDER, Madrid, Spain.,9 Institute for Neurosciences, Miguel Hernández University-CSIC, Alicante, Spain
| | - Jorge Manzanares
- 5 Red temática de Investigación cooperativa en salud (RETIS-Trastornos adictivos), Instituto Carlos III, MICINN and FEDER, Madrid, Spain.,9 Institute for Neurosciences, Miguel Hernández University-CSIC, Alicante, Spain
| | - Gabriel Rubio
- 2 Research Institute 12-i, Madrid, Spain.,3 Hospital Universitario 12 de Octubre, Madrid, Spain.,4 Department of Psychiatry, Complutense University of Madrid, Madrid, Spain.,5 Red temática de Investigación cooperativa en salud (RETIS-Trastornos adictivos), Instituto Carlos III, MICINN and FEDER, Madrid, Spain
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Grimsley CA, Longenecker RJ, Rosen MJ, Young JW, Grimsley JM, Galazyuk AV. An improved approach to separating startle data from noise. J Neurosci Methods 2015; 253:206-17. [PMID: 26165984 PMCID: PMC4560645 DOI: 10.1016/j.jneumeth.2015.07.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 07/01/2015] [Accepted: 07/01/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND The acoustic startle reflex (ASR) is a rapid, involuntary movement to sound, found in many species. The ASR can be modulated by external stimuli and internal state, making it a useful tool in many disciplines. ASR data collection and interpretation varies greatly across laboratories making comparisons a challenge. NEW METHOD Here we investigate the animal movement associated with a startle in mouse (CBA/CaJ). Movements were simultaneously captured with high-speed video and a piezoelectric startle plate. We also use simple mathematical extrapolations to convert startle data (force) into center of mass displacement ("height"), which incorporates the animal's mass. RESULTS Startle plate force data revealed a stereotype waveform associated with a startle that contained three distinct peaks. This waveform allowed researchers to separate trials into 'startles' and 'no-startles' (termed 'manual classification). Fleiss' kappa and Krippendorff"s alpha (0.865 for both) indicate very good levels of agreement between researchers. Further work uses this waveform to develop an automated startle classifier. The automated classifier compares favorably with manual classification. A two-way ANOVA reveals no significant difference in the magnitude of the 3 peaks as classified by the manual and automated methods (P1: p=0.526, N1: p=0.488, P2: p=0.529). COMPARISON WITH EXISTING METHOD(S) The ability of the automated classifier was compared with three other commonly used classification methods; the automated classifier far outperformed these methods. CONCLUSIONS The improvements made allow researchers to automatically separate startle data from noise, and normalize for an individual animal's mass. These steps ease inter-animal and inter-laboratory comparisons of startle data.
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Affiliation(s)
- Calum A Grimsley
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Ryan J Longenecker
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA; Biomedical Sciences Program, Kent State University, Kent, OH, USA
| | - Merri J Rosen
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Jesse W Young
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Jasmine M Grimsley
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Alexander V Galazyuk
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
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Winton-Brown T, Kumari V, Windler F, Moscoso A, Stone J, Kapur S, McGuire P. Sensorimotor gating, cannabis use and the risk of psychosis. Schizophr Res 2015; 164:21-7. [PMID: 25801237 PMCID: PMC4435667 DOI: 10.1016/j.schres.2015.02.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 02/16/2015] [Accepted: 02/21/2015] [Indexed: 12/13/2022]
Abstract
Sensorimotor gating, measured as the modification of eye blink startle reflexes to loud acoustic stimuli by quieter preceding stimuli, is altered in those with psychosis, their relatives and those at high clinical risk for psychosis. Alterations have also been shown in cannabis users, albeit to a lesser extent, and cannabis is a known risk factor for the onset of psychosis in clinically and genetically susceptible individuals. We examined the interaction between clinical risk for psychosis and cannabis use on sensorimotor gating, both Prepulse Inhibition (PPI) and Prepulse Facilitation (PPF). We tested PPI and PPF in participants with an At Risk Mental State (ARMS) for psychosis and a matched control group. Both groups included a proportion of subjects who had recently used cannabis, as confirmed by urinary drug screening (UDS) on the day of testing. We found that ARMS participants showed reduced PPF and PPI relative to controls, the latter driven by a group by cannabis use interaction, with recent use reducing PPI in ARMS participants but not in controls. When the analysis was limited to UDS-negative participants there was significantly reduced PPF in ARMS subjects relative to controls, but no differences in PPI. Within the ARMS group reduced sensorimotor gating, measured by both PPI and PPF, related to reduced overall level of function. Cannabis use in clinical high risk individuals may increase the risk of psychosis in part through worsening PPI, while PPF is altered in ARMS individuals irrespective of cannabis use. This develops our understanding of cognitive mechanisms leading to the experience of aberrant perceptual phenomena and the subsequent development of psychotic symptoms.
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Affiliation(s)
- T. Winton-Brown
- Department of Psychosis Studies, Institute of Psychiatry, Kings College London, United Kingdom,Corresponding author at: PO 67 Institute of Psychiatry, De Crespigny Park, London, United Kingdom. Tel.: + 44 61481262243.
| | - V. Kumari
- Department of Psychology, Institute of Psychiatry, Kings College London, United Kingdom
| | - F. Windler
- Center of Advanced European Studies and Research, Bonn, Germany
| | - A. Moscoso
- Department of Child and Adolescent Psychiatry, Hospital de D. Estefânia Lisboa, Portugal
| | - J. Stone
- Department of Psychosis Studies, Institute of Psychiatry, Kings College London, United Kingdom
| | - S. Kapur
- Department of Psychosis Studies, Institute of Psychiatry, Kings College London, United Kingdom
| | - P. McGuire
- Department of Psychosis Studies, Institute of Psychiatry, Kings College London, United Kingdom
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Developmentally vitamin D-deficient rats show enhanced prepulse inhibition after acute Δ9-tetrahydrocannabinol. Behav Pharmacol 2014; 25:236-44. [PMID: 24776491 DOI: 10.1097/fbp.0000000000000041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Developmental vitamin D (DVD) deficiency has been proposed as a risk factor for schizophrenia. DVD-deficient rats show selective cognitive deficits and novelty-induced hyperlocomotion and enhanced locomotor responses from acute treatment with psychomimetic drugs, such as amphetamine and MK-801. Here we aimed to examine the effect of a drug from a different class of psychomimetic/psychoactive compounds, Δ9-tetrahydrocannabinol (THC), on tasks of relevance to the cognitive and positive symptoms of schizophrenia. The aim of this study was to investigate whether DVD deficiency modulates the behavioural effects of THC on tests of delay-dependent memory, sensorimotor gating and locomotion. Adult control and DVD-deficient rats were injected with THC (0, 0.3, 0.6, 1.25, 2.5 mg/kg) 15 min before a delay match to sample (DMTS) task using variable delays (0-24 s). A separate group of rats was injected with either 2.5 mg/kg THC or vehicle before tests of either prepulse inhibition (PPI) of the acoustic startle response or in the open field. Control and DVD-deficient rats showed a similar dose-dependent impairment in performance on the DMTS. The greatest impairment was observed at 2.5 mg/kg for all delays (0-24 s). DVD-deficient rats showed THC-induced enhancement of PPI, which was not observed in control rats. There was no effect of maternal diet on acoustic startle response or locomotor responses in the open field. This study reports the novel findings that DVD-deficient rats were more sensitive to the acute effects of THC on PPI. It appears that prenatal vitamin D deficiency has long-term effects on sensitivity to the behavioural effects of cannabinoids.
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Klug M, van den Buuse M. An investigation into "two hit" effects of BDNF deficiency and young-adult cannabinoid receptor stimulation on prepulse inhibition regulation and memory in mice. Front Behav Neurosci 2013; 7:149. [PMID: 24155701 PMCID: PMC3800788 DOI: 10.3389/fnbeh.2013.00149] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 10/01/2013] [Indexed: 11/13/2022] Open
Abstract
Reduced brain-derived neurotrophic factor (BDNF) signaling has been shown in the frontal cortex and hippocampus in schizophrenia. The aim of the present study was to investigate whether a BDNF deficit would modulate effects of chronic cannabis intake, a well-described risk factor for schizophrenia development. BDNF heterozygous mice (HET) and wild-type controls were chronically treated during weeks 6, 7, and 8 of life with the cannabinoid receptor agonist, CP55,940 (CP). After a 2-week delay, there were no CP-induced deficits in any of the groups in short-term spatial memory in a Y-maze task or novel object recognition memory. Baseline prepulse inhibition (PPI) was lower but average startle was increased in BDNF HET compared to wild-type controls. Acute CP administration before the PPI session caused a marked increase in PPI in male HET mice pre-treated with CP but not in any of the other male groups. In females, there were small increases of PPI in all groups upon acute CP administration. Acute CP administration furthermore reduced startle and this effect was greater in HET mice irrespective of chronic CP pre-treatment. Analysis of the levels of [3H]CP55,940 binding by autoradiography revealed a significant increase in the nucleus accumbens of male BDNF HET mice previously treated with CP but not in any of the other groups or in the caudate nucleus. These results show that BDNF deficiency and chronic young-adult cannabinoid receptor stimulation do not interact in this model on learning and memory later in life. In contrast, male “two hit” mice, but not females, were hypersensitive to the effect of acute CP on sensorimotor gating. These effects may be related to a selective increase of [3H]CP55,940 binding in the nucleus accumbens, reflecting up-regulation of CB1 receptor density in this region. These data could be of relevance to our understanding of differential “two hit” neurodevelopmental mechanisms in schizophrenia.
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Affiliation(s)
- Maren Klug
- Behavioural Neuroscience Laboratory, Mental Health Research Institute Melbourne, VIC, Australia ; Department of Psychology, Swinburne University of Technology Hawthorn, VIC, Australia
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Increased sensorimotor gating in recreational and dependent cocaine users is modulated by craving and attention-deficit/hyperactivity disorder symptoms. Biol Psychiatry 2013; 73:225-34. [PMID: 22959126 DOI: 10.1016/j.biopsych.2012.08.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/03/2012] [Accepted: 08/03/2012] [Indexed: 02/01/2023]
Abstract
BACKGROUND Cocaine dependence has been associated with blunted dopamine and norepinephrine signaling, but it is unknown if recreational cocaine use is also associated with alterations of catecholamine systems. Prepulse inhibition (PPI) of the acoustic startle response-a measure of sensorimotor gating-is highly sensitive for manipulations of the catecholamine system. Therefore, we investigated whether relatively pure recreational users (RCU) and dependent cocaine users (DCU) display alterations of PPI, startle reactivity, and habituation. Moreover, the influences of methylenedioxymethamphetamine and cannabis co-use, craving, and attention-deficit/hyperactivity disorder (ADHD) symptoms on startle measures were examined. METHODS In 64 RCU, 29 DCU, and 66 stimulant-naïve control subjects, PPI of acoustic startle response, startle reactivity, habituation, ADHD symptoms, and cocaine craving were assessed. Drug use of all participants was controlled by hair and urine toxicologies. RESULTS Both RCU and DCU showed increased PPI in comparison with control participants (Cohen's d=.38 and d=.67, respectively), while RCU and DCU did not differ in PPI measures (d=.12). No significant group differences were found in startle reactivity or habituation measures. In cocaine users, PPI was positively correlated with cumulative cocaine dose used, craving for cocaine, and ADHD symptoms. Users with a diagnosis of ADHD and strong craving symptoms displayed the highest PPI levels compared with control subjects (d=.78). CONCLUSIONS The augmented PPI in RCU and DCU suggests that recreational use of cocaine is associated with altered catecholamine signaling, in particular if ADHD or craving symptoms are present. Finally, ADHD might be a critical risk factor for cocaine-induced changes of the catecholamine system.
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Narang D, Kerr PM, Baserman J, Tam R, Yang W, Searle G, Manning-Fox JE, Paulsen IM, Kozuska JL, MacDonald PE, Light PE, Holt A, Plane F. Triton X-100 inhibits L-type voltage-operated calcium channels. Can J Physiol Pharmacol 2013; 91:316-24. [PMID: 23627843 DOI: 10.1139/cjpp-2012-0257] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Triton X-100 (TX-100) is a nonionic detergent frequently used at millimolar concentrations to disrupt cell membranes and solubilize proteins. At low micromolar concentrations, TX-100 has been reported to inhibit the function of potassium channels. Here, we have used electrophysiological and functional techniques to examine the effects of TX-100 on another class of ion channels, L-type voltage-operated calcium channels (VOCCs). TX-100 (30 nmol·L(-1) to 3 μmol·L(-1)) caused reversible concentration-dependent inhibition of recombinant L-type VOCC (CaV 1.2) currents and of native L-type VOCC currents recorded from rat vascular smooth muscle cells and cardiac myocytes, and murine and human pancreatic β-cells. In functional studies, TX-100 (165 nmol·L(-1) to 3.4 μmol·L(-1)) caused concentration-dependent relaxation of rat isolated mesenteric resistance arteries prestimulated with phenylephrine or KCl. This effect was independent of the endothelium. TX-100 (1.6 μmol·L(-1)) inhibited depolarization-induced exocytosis in both murine and human isolated pancreatic β-cells. These data indicate that at concentrations within the nanomolar to low micromolar range, TX-100 significantly inhibits L-type VOCC activity in a number of cell types, an effect paralleled by inhibition of cell functions dependent upon activation of these channels. This inhibition occurs at concentrations below those used to solubilize proteins and may compromise the use of solutions containing TX-100 in bioassays.
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Affiliation(s)
- Deepak Narang
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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Pharmacological effects of cannabinoids on the reference and working memory functions in mice. Psychopharmacology (Berl) 2013; 225:483-94. [PMID: 22903389 DOI: 10.1007/s00213-012-2834-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 07/30/2012] [Indexed: 10/28/2022]
Abstract
RATIONALE Evidence indicates cannabinoid receptor agonists impair performance in procedures to assess memory that may also be confounded by motivational or motor effects, both of which occur with cannabinoids. Thus, convergence of evidence from a variety of procedures that differ in motivation, attention, arousal and response requirements, but share a common reliance on memory, is required. There are no current reports on cannabinoid effects on mice tested in the radial arm maze. OBJECTIVES The objective was to determine the effects of the cannabinoid agonist CP 55940 and the dependence of any such effects on the CB1 receptor using the CB1 receptor antagonist SR 141716A on two strains of mice in the eight-arm radial maze procedure. METHODS Male C57BL/6J (N = 36) and C3H/HEJ (N = 12) mice were trained to a criterion and then were treated (IP) with vehicle + vehicle, SR 141716A + vehicle, vehicle + CP 55940 and SR 141716A + CP 55940 in a fully balanced mixed design prior to further tests in the maze. Reference (long-term) and working (short-term) memory were assessed. RESULTS CP 55940 impaired performance of the reference memory task in the C57BL/6J strain but not the C3H/HEJ strain; SR 141716A reversed the effect of CP 55940 on these measures. CP 55940 also increased working memory errors in the C57BL/6J mice only, which was not affected by SR 141716A. CONCLUSION The present study provides evidence for a strain-specific effect of a dose of CP 55940 on reference memory. While the cannabinoid agonist also impaired working memory in one strain, this effect was apparently not mediated by CB1 receptors.
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Avdesh A, Cornelisse V, Martin-Iverson MT. Corticosteroid dependent and independent effects of a cannabinoid agonist on core temperature, motor activity, and prepulse inhibition of the acoustic startle reflex in Wistar rats. Psychopharmacology (Berl) 2012; 220:405-15. [PMID: 21947354 DOI: 10.1007/s00213-011-2493-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 09/03/2011] [Indexed: 10/17/2022]
Abstract
RATIONALE There are inconsistent reports on the effects of cannabinoid agonists on prepulse inhibition of the startle reflex (PPI) with increases, decreases, and no effects. It has been hypothesized that the conflicting observations may be as a result of modulation of the effects of cannabinoid agonists by the regulation of corticosteroid release. OBJECTIVE The purpose of the present study was to determine the effects of CP55940, a cannabinoid agonist, and metyrapone, a corticosteroid synthesis inhibitor on core temperature, motor activity, the startle reflex, and PPI. METHODS Startle responses were measured in 64 male Wistar rats while varying startling stimulus intensities, analogous to dose-response curves. A stimulus potency measure (ES(50)) and a response measure, the maximal achievable response (R (MAX)) were derived from the stimulus-response curves. RESULTS CP55940 reduced core temperature and motor activity; these effects were potentiated by metyrapone. CP55940 increased R (MAX) of startle in the absence of a prepulse by a corticosteroid-dependent mechanism but decreased it when metyrapone was administered before CP55940, a corticosteroid-independent mechanism. The inverse of stimulus potency (ES(50)) was not affected by either drug alone but was increased by the combined drugs. CP55940 increased the prepulse motor gating effects and decreased the prepulse sensory gating effects of the same prepulses but only when given after metyrapone. CONCLUSIONS The most parsimonious interpretation of these effects is that CP55940 has some effects through corticosteroid-dependent actions and opposite effects by corticosteroid-independent actions. These two putative sites of actions affect stimulus gating opposite to their effects on response gating.
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Affiliation(s)
- Avdesh Avdesh
- Centre for Clinical Research in Neuropsychiatry, Graylands Hospital, The University of Western Australia, Perth, Western Australia, Australia
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Mathias CW, Blumenthal TD, Dawes MA, Liguori A, Richard DM, Bray B, Tong W, Dougherty DM. Failure to sustain prepulse inhibition in adolescent marijuana users. Drug Alcohol Depend 2011; 116:110-6. [PMID: 21196088 PMCID: PMC3091950 DOI: 10.1016/j.drugalcdep.2010.11.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 11/10/2010] [Accepted: 11/30/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND Marijuana use is typically initiated during adolescence, which is a critical period for neural development. Studies have reported reductions in prepulse inhibition (PPI) among adults who use marijuana chronically, although no human studies have been conducted during the critical adolescent period. METHODS This study tested PPI of acoustic startle among adolescents who were either frequent marijuana users or naïve to the drug (Controls). Adolescents were tested using two intensities of prepulses (70 and 85 dB) combined with a 105 dB startle stimulus, delivered across two testing blocks. RESULTS There was a significant interaction of group by block for PPI; marijuana users experienced a greater decline in the PPI across the testing session than Controls. The change in PPI of response magnitude for users was predicted by change in urine THC/creatinine after at least 18 h of abstinence, the number of joints used during the previous week before testing, as well as self-reported DSM-IV symptoms of marijuana tolerance, and time spent using marijuana rather than participating in other activities. CONCLUSIONS These outcomes suggest that adolescents who are frequent marijuana users have problems maintaining prepulse inhibition, possibly due to lower quality of information processing or sustained attention, both of may contribute to continued marijuana use as well as attrition from marijuana treatment.
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Affiliation(s)
- Charles W. Mathias
- Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | | | - Michael A. Dawes
- Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Anthony Liguori
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Dawn M. Richard
- Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Bethany Bray
- Department of Psychology, Virginia Polytechnic University, Blacksburg, VA
| | - Weiqun Tong
- Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Donald M. Dougherty
- Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX
- Corresponding author: Donald M. Dougherty, Ph.D., Division of Neurobehavioral Research, Psychiatry Department, The University of Texas Health Science Center at San Antonio, NRLC MC 7793, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA,
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Fernandez-Espejo E, Viveros MP, Núñez L, Ellenbroek BA, Rodriguez de Fonseca F. Role of cannabis and endocannabinoids in the genesis of schizophrenia. Psychopharmacology (Berl) 2009; 206:531-49. [PMID: 19629449 DOI: 10.1007/s00213-009-1612-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 07/02/2009] [Indexed: 11/25/2022]
Abstract
RATIONALE Cannabis abuse and endocannabinoids are associated to schizophrenia. OBJECTIVES It is important to discern the association between schizophrenia and exogenous Cannabis sativa, on one hand, and the endogenous cannabinoid system, on the other hand. RESULTS On one hand, there is substantial evidence that cannabis abuse is a risk factor for psychosis in genetically predisposed people, may lead to a worse outcome of the disease, or it can affect normal brain development during adolescence, increasing the risk for schizophrenia in adulthood. Regarding genetic predisposition, alterations affecting the cannabinoid CNR1 gene could be related to schizophrenia. On the other hand, the endogenous cannabinoid system is altered in schizophrenia (i.e., increased density of cannabinoid CB1 receptor binding in corticolimbic regions, enhanced cerebrospinal fluid anandamide levels), and dysregulation of this system can interact with neurotransmitter systems in such a way that a "cannabinoid hypothesis" can be integrated in the neurobiological hypotheses of schizophrenia. Finally, there is also evidence that some genetic alterations of the CNR1 gene can act as a protectant factor against schizophrenia or can induce a better pharmacological response to atypical antipsychotics. CONCLUSIONS Cannabis abuse is a risk factor for psychosis in predisposed people, it can affect neurodevelopment during adolescence leading to schizophrenia, and a dysregulation of the endocannabinoid system can participate in schizophrenia. It is also worth noting that some specific cannabinoid alterations can act as neuroprotectant for schizophrenia or can be a psychopharmacogenetic rather than a vulnerability factor.
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Affiliation(s)
- Emilio Fernandez-Espejo
- Departamento de Fisiología Médica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.
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Dissanayake DWN, Zachariou M, Marsden CA, Mason R. Auditory gating in rat hippocampus and medial prefrontal cortex: effect of the cannabinoid agonist WIN55,212-2. Neuropharmacology 2008; 55:1397-404. [PMID: 18809420 DOI: 10.1016/j.neuropharm.2008.08.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 06/25/2008] [Accepted: 08/28/2008] [Indexed: 10/21/2022]
Abstract
Sensory gating can be assessed in rodents and humans using an auditory conditioning (C)-test (T) paradigm, with schizophrenic patients exhibiting a loss of gating. Dysregulation of the endocannabinoid system has been proposed to be involved in the pathogenesis of schizophrenia. We studied auditory gating and the effects of the cannabinoid agonist WIN55,212-22 on gating in CA3 and dentate gyrus (DG) of the hippocampus and medial prefrontal cortex (mPFC) in male Lister hooded rats using in vivo electrophysiology. The effects of a single dose of WIN55,212-2 on the N2 local field potential (LFP) test/conditioning amplitude ratios (T/C ratio) and response latencies were examined. In rats that demonstrated gating of N2, mPFC showed higher T/C ratios and shorter conditioning response latencies compared to DG and CA3. WIN55,212-2 disrupted auditory gating in all three areas with a significant increase in test amplitudes in the gating rats. A group of non-gating rats demonstrated higher test amplitudes and higher T/C ratios compared to gating rats. WIN55,212-2 had no effect on T/C ratios in the non-gating rats. The cannabinoid receptor (CB1) antagonist SR141716A prevented WIN55,212-2 induced disruption of gating. This study demonstrates gated auditory-evoked responses in CA3, DG and mPFC. The mPFC showed an early phase of gating which may later be modulated by CA3 and DG activity. Furthermore, cannabinoid receptor activation disrupted auditory gating in CA3, DG and mPFC, an effect which was prevented by CB1 receptor antagonism. The results further demonstrate the presence of a non-gating rat population which responded differently to cannabinoid agonists.
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Affiliation(s)
- Dilshani W N Dissanayake
- School of Biomedical Sciences, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, Nottinghamshire NG7 2UH, UK.
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15
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Malone DT, Kearn CS, Chongue L, Mackie K, Taylor DA. Effect of social isolation on CB1 and D2 receptor and fatty acid amide hydrolase expression in rats. Neuroscience 2008; 152:265-72. [PMID: 18082330 DOI: 10.1016/j.neuroscience.2007.10.043] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 10/25/2007] [Accepted: 10/25/2007] [Indexed: 11/17/2022]
Abstract
Rearing rats in isolation has been shown to produce behavioral and neurochemical alterations similar to those observed in psychoses such as schizophrenia. Also, a dysregulation in both the endocannabinoid and dopaminergic systems has been implicated in schizophrenia. The aim of this study was to determine if there are differences in CB1 receptor and fatty acid amide hydrolase (FAAH) protein expression, as well as D2 dopamine receptor expression in different brain regions in rats reared in different environmental conditions. Twenty-one-day-old male Sprague-Dawley rats were either reared in individual cages (isolated rats) or in group cages of six per cage (group-housed rats) for 8 weeks. Quantitative fluorescence immunohistochemistry was performed on brain slices using antibodies specific to the CB1 or D2 receptor, or the enzyme FAAH. Raising rats in isolation led to a significant decrease in CB1 receptor expression in the caudate putamen and the amygdala, a significant increase in FAAH expression in the caudate putamen and the nucleus accumbens core and shell, and no significant change in D2 receptor expression in any region studied. These results indicate that the endocannabinoid system is altered in an animal model of aspects of psychosis. This implies that rearing rats under different housing conditions may provide new insight into the role of the endocannabinoid system in the development of psychoses.
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Affiliation(s)
- D T Malone
- Department of Pharmaceutical Biology, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia.
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Ballmaier M, Bortolato M, Rizzetti C, Zoli M, Gessa G, Heinz A, Spano P. Cannabinoid receptor antagonists counteract sensorimotor gating deficits in the phencyclidine model of psychosis. Neuropsychopharmacology 2007; 32:2098-107. [PMID: 17299506 DOI: 10.1038/sj.npp.1301344] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Clinical and laboratory findings suggest that cannabinoids and their receptors are implicated in schizophrenia. The role of cannabinoids in schizophrenia remains however poorly understood, as data are often contradictory. The primary aim of this study was to investigate whether the cannabinoid CB1 receptor antagonists rimonabant and AM251 are able to reverse deficits of sensorimotor gating induced by phencyclidine and to mimic the 'atypical' antipsychotic profile of clozapine. The prepulse inhibition (PPI) of the startle reflex was used to measure deficits of sensorimotor gating. PPI-disruptive effects of phencyclidine and their antagonism by rimonabant, AM251, and clozapine were studied in rats. The effects of rimonabant were carefully examined taking into account dose ranges, vehicle, and route of administration. We also examined the ability of rimonabant to reduce the PPI-disruptive effects of dizocilpine and apomorphine. Rimonabant as well as AM251 significantly counteracted the phencyclidine-disruptive model of PPI, comparable to the restoring effect of clozapine; no augmentation effect was observed with rimonabant and clozapine as cotreatment. Rimonabant also significantly attenuated the PPI disruptive effects of dizocilpine and apomorphine. Taken together, our results indicate that CB1 receptor antagonists do produce 'atypical' antipsychotic profile mimicking that of clozapine in the phencyclidine disruption of sensorimotor gating. Our findings further suggest that CB1 receptor antagonism may be involved in restoring disturbed interactions between the activity of the endocannabinoid system and glutamate neurotransmitter system implied in schizophrenia.
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Affiliation(s)
- Martina Ballmaier
- Department of Psychiatry and Psychotherapy, Charité University Medicine, Campus Mitte, Shumannstrasse 20/21, 10117 Berlin, Germany.
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17
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Boucher AA, Arnold JC, Duffy L, Schofield PR, Micheau J, Karl T. Heterozygous neuregulin 1 mice are more sensitive to the behavioural effects of Delta9-tetrahydrocannabinol. Psychopharmacology (Berl) 2007; 192:325-36. [PMID: 17333138 DOI: 10.1007/s00213-007-0721-3] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 01/22/2007] [Indexed: 02/05/2023]
Abstract
RATIONALE Cannabis use may precipitate schizophrenia especially if the individual has a genetic vulnerability to this mental disorder. Human and animal research indicates that neuregulin 1 (Nrg1) is a susceptibility gene for schizophrenia. OBJECTIVES The aim of this study was to investigate whether dysfunction in the Nrg1 gene modulates the behavioural effects of Delta(9)-tetrahydrocannabinol (THC), the major psychotropic component of cannabis. MATERIALS AND METHODS Heterozygous Nrg1 transmembrane-domain knockout mice (Nrg1 HET) were treated with acute THC (0, 5 or 10 mg/kg i.p.) 30 min before being tested using open field (OF), hole board (HB), light-dark (LD), elevated plus maze (EPM), social interaction (SI) and prepulse inhibition (PPI) tests. RESULTS Nrg1 HET mice showed differences in baseline behaviour with regard to locomotor activity, exploration and anxiety. More importantly, they were more sensitive to the locomotor suppressant actions of THC compared to wild type-like (WT) mice. In addition, Nrg1 HET mice expressed a greater THC-induced enhancement in % PPI than WT mice. The effects of THC on anxiety-related behaviour were task-dependent, with Nrg1 HET mice being more susceptible than WT mice to the anxiogenic effects of THC in LD, but not in the EPM, SI and OF tests. CONCLUSIONS Nrg1 HET mice were more sensitive to the acute effects of THC in an array of different behaviours including those that model symptoms of schizophrenia. It appears that variation in the schizophrenia-related neuregulin 1 gene alters the sensitivity to the behavioural effects of cannabinoids.
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Affiliation(s)
- A A Boucher
- Neuroscience Institute of Schizophrenia and Allied Disorders, 384 Victoria Street, Darlinghurst, NSW, 2010, Australia
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18
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Kedzior KK, Martin-Iverson MT. Chronic cannabis use is associated with attention-modulated reduction in prepulse inhibition of the startle reflex in healthy humans. J Psychopharmacol 2006; 20:471-84. [PMID: 16174673 DOI: 10.1177/0269881105057516] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Regardless of a wide research interest the nature of a relationship between cannabis use and schizophrenia is controversial. One of the physiological abnormalities in schizophrenia is attention-modulated deficit in prepulse inhibition (PPI), which is a normal reduction in the startle reflex magnitude when a non-startling stimulus (prepulse) precedes the startling stimulus (pulse). This experiment was designed to determine whether or not otherwise healthy people using cannabis would exhibit attention-modulated deficit in PPI. The startle reflex was recorded in carefully screened healthy humans attending to and ignoring auditory pulse and prepulse stimuli separated by short (20-200 ms) and long prepulse intervals (1600 ms). In contrast to 12 non-using controls, cannabis use in 16 healthy humans was associated with significant reduction in%PPI while attending to auditory stimuli, but not while ignoring them. The PPI was correlated with the duration of cannabis use but not with the concentration of cannabinoid metabolites in urine and the recency of cannabis use in the preceding 24 hours. Cannabis use was not associated with changes in prepulse facilitation of startle reflex magnitude (%PPF) at long prepulse intervals, prepulse facilitation of startle reflex latency and startle reflex magnitude in the absence of prepulses. These results suggest that chronic, but not acute, use of cannabis is associated with schizophrenia-like disruption in PPI in healthy controls. Such reduction in PPI is attention-dependent and does not reflect a global deficit in sensorimotor gating in cannabis users.
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Affiliation(s)
- Karina K Kedzior
- Centre for Clinical Research in Neuropsychiatry, Graylands Hospital, Mt Claremont WA 6190, Australia.
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19
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Pickel VM, Chan J, Kearn CS, Mackie K. Targeting dopamine D2 and cannabinoid-1 (CB1) receptors in rat nucleus accumbens. J Comp Neurol 2006; 495:299-313. [PMID: 16440297 PMCID: PMC1698281 DOI: 10.1002/cne.20881] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The nucleus accumbens (Acb) shell and core are essential components of neural circuitry mediating the reward and motor effects produced by activation of dopamine D2 or cannabinoid-1 (CB1) receptors. D2 receptors can form heterodimeric complexes with cannabinoid-1 (CB1) receptors and are also involved in control of the availability of both dopamine and endocannabinoids. Thus, the subcellular locations of D2 and CB1 receptors with respect to each other are implicit to their physiological actions in the Acb. We used electron microscopic immunocytochemistry to determine these locations in the Acb shell and core of rat brain. In each region, many neuronal profiles showed endomembrane and plasmalemmal distributions of one or both receptors. Approximately one-third of the labeled profiles were somata and dendrites, some of which showed overlapping subcellular distributions of D2 and CB1 immunoreactivities. The remaining labeled profiles were small axons and axon terminals containing CB1 and/or D2 receptors. Of the labeled terminals forming recognizable synapses, approximately 20% of those containing CB1 receptors contacted D2-labeled dendrites, while conversely, almost 15% of those containing D2 receptors contacted CB1-labeled dendrites. These results provide the first ultrastructural evidence that D2 and CB1 receptors in the Acb shell and core have subcellular distributions supporting both intracellular associations and local involvement of D2 receptors in making available endocannabinoids that are active on CB1 receptors in synaptic neurons. These distributions have direct relevance to the rewarding and euphoric as well as motor effects produced by marijuana and by addictive drugs enhancing dopamine levels in the Acb.
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Affiliation(s)
- Virgina M Pickel
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10021, USA.
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20
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Schneider M, Drews E, Koch M. Behavioral effects in adult rats of chronic prepubertal treatment with the cannabinoid receptor agonist WIN 55,212-2. Behav Pharmacol 2006; 16:447-54. [PMID: 16148450 DOI: 10.1097/00008877-200509000-00018] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Human and animal studies provide evidence for vulnerable periods of brain development for deleterious effects of cannabinoids. We have recently shown that pubertal chronic cannabinoid treatment leads to long-lasting behavioral deficits, whereas a comparable treatment in adult rats did not affect the animals' behavior. In the present study we examined the effects of an identical chronic cannabinoid treatment in juvenile rats, just before the onset of puberty. Treatment with the synthetic cannabinoid agonist WIN 55,212-2 (WIN) (1.2 mg/kg) or vehicle was extended over 25 days throughout the prepubertal period (postnatal days 15-40) in juvenile rats. The rats received a total of 20 injections intraperitoneally. Adult rats were tested for object recognition memory, performance in a progressive ratio (PR) operant behavior task, locomotor activity and prepulse inhibition (PPI) of the acoustic startle response. Juvenile chronic WIN administration had no effect on object recognition memory, PR performance and locomotor activity in adulthood. However, a PPI deficit was observed in WIN-treated rats when tested as adults that could be reversed by the acute administration of the dopamine receptor antagonist haloperidol (0.1 mg/kg). Additionally, juvenile cannabinoid treatment reduced the number of rearings, as well as the time spent in the center of the open field in adult rats, suggesting increased anxiety. Juvenile chronic cannabinoid treatment induced behavioral disturbances in adult rats that are less severe than those observed after pubertal cannabinoid administration. However, based on the observations of sensorimotor gating deficits and increased anxiety, we conclude that the prepubertal developmental phase, in addition to puberty, also represents a vulnerable time period for persistent adverse effects of cannabinoids.
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Affiliation(s)
- M Schneider
- Department of Psychiatry and Psychotherapy, University of Cologne, Cologne, Germany
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21
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Malone DT, Taylor DA. The effect of Delta9-tetrahydrocannabinol on sensorimotor gating in socially isolated rats. Behav Brain Res 2005; 166:101-9. [PMID: 16143410 DOI: 10.1016/j.bbr.2005.07.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 07/19/2005] [Accepted: 07/20/2005] [Indexed: 11/24/2022]
Abstract
Rearing rats in isolation produces behavioural and neurochemical alterations similar to those observed in schizophrenia. Cannabinoids have also been implicated in inducing psychotic symptoms. In this study, we investigate the effect of the major psychoactive constituent of cannabis and partial cannabinoid CB(1) receptor agonist Delta(9)-tetrahydrocannabinol (THC) on prepulse inhibition (%PPI) of the acoustic startle reflex and on habituation in socially isolated and grouped rats. Deficits in %PPI are reminiscent of sensorimotor gating deficits observed in psychoses. Male Sprague-Dawley rat pups (21 days old) were housed in either single cages (isolated) or in group cages of six per cage (grouped). Eight weeks later the effect of vehicle, THC and the CB(1) receptor antagonist SR 141716 on %PPI was tested. Vehicle treated isolated rats exhibited significantly reduced PPI compared with grouped rats. Isolated rats treated with THC had significantly lower %PPI than vehicle treated groups. This further decrease of %PPI by THC was reversed by pre-treatment with SR 141716, indicating that this effect was mediated by CB(1) receptors. THC had no significant effect on %PPI in grouped rats. SR 141716 had no significant effect on %PPI in either grouped or isolated rats. Habituation did not significantly alter in any treatment group in any treatment group. These results suggest that THC produces significant decreases in sensorimotor gating in rats with already dysfunctional sensorimotor gating processes, but not in normal rats. The lack of effect of SR 141716 in either grouped or isolated rats suggests that normal endocannabinoid function is not critical in sensorimotor gating processes.
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Affiliation(s)
- Daniel Thomas Malone
- Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, Parkville 3052, Vic., Australia.
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22
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Martin-Iverson MT, Stevenson KN. Apomorphine effects on emotional modulation of the startle reflex in rats. Psychopharmacology (Berl) 2005; 181:60-70. [PMID: 15772861 DOI: 10.1007/s00213-005-2217-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2004] [Accepted: 01/20/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Emotional modulation of the startle reflex in the rat may be used to assess whether activation of dopamine receptors specifically increases hedonia, incentive, fear or arousal. OBJECTIVES The objective of the study is to determine the effects of apomorphine (0.8 mg/kg s.c.) on the startle reflex of rats (72 male Sprague-Dawley rats) exposed to one of three affective conditions. These conditions were negative affective stimulus (exposure to cat smell), positive affective stimulus (availability of a 20% sucrose solution), neutral stimulus (no additional affective stimulus) and one of two appetitive "drive" states (food deprived or non-food deprived). METHODS The startle response (whole-body flinch response) was measured after presentation of a range of intensities of acoustic stimuli (65-120 dB, 40-ms duration white noise). The resulting sigmoidal stimulus intensity-response magnitude (SIRM) curves were fitted using a logistic regression procedure, and features of these functions were abstracted for analysis. RESULTS Maximal startle amplitudes were increased by the negative affect (fear) stimulus in non-food-deprived rats and decreased by the positive affect stimulus in food-deprived rats. Apomorphine mimicked the effects of food deprivation under both affect conditions, but also produced an effect in food-deprived rats similar to that of the positive affect condition. CONCLUSIONS The results are consistent with both a positive incentive effect and a direct hedonic action of apomorphine, but inconsistent with a role in general arousal. In addition, a method of analysing SIRM functions with logistic regressions is introduced as a useful means of standardising startle reflex measurements.
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Affiliation(s)
- Mathew T Martin-Iverson
- School of Medicine and Pharmacology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
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Bortolato M, Aru GN, Frau R, Orrù M, Luckey GC, Boi G, Gessa GL. The CB receptor agonist WIN 55,212-2 fails to elicit disruption of prepulse inhibition of the startle in Sprague-Dawley rats. Psychopharmacology (Berl) 2005; 177:264-71. [PMID: 15290008 DOI: 10.1007/s00213-004-1941-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Accepted: 05/19/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE A growing evidentiary body indicates cannabinoid exposure is conducive to cognitive impairment and psychotic phenomena in vulnerable individuals. In this respect, recent studies have displayed controversial results on the ability of cannabinoids to elicit sensorimotor gating alterations and attentional filtering, whose disruption is a distinctive feature of psychosis. OBJECTIVES The goal of this study was to investigate the effects of acute, subchronic, and chronic treatment with the synthetic CB receptor agonist WIN 55,212-2 (WIN) on prepulse inhibition (PPI) of the acoustic startle reflex (ASR), a powerful paradigm for evaluation of sensorimotor gating. METHODS Different groups of adult Sprague-Dawley rats were treated with 0.5, 1, and 2 mg/kg WIN (i.p.) acutely, as well as for 7 days and 21 days. All animals underwent testing 40 min after the last treatment and their evaluation was compared with that of animals treated with vehicle. In a separate group, the effects of WIN withdrawal were also analyzed, 24 h after discontinuation of a 21-day treatment. RESULTS No variation in PPI was detected in any of the test groups when compared with controls, whatever the dosage and the treatment. CONCLUSIONS These findings suggest WIN does not impair sensorimotor gating in Sprague-Dawley rats and confirm clinical evidence according to which cannabis is an unlikely causative of psychosis among non-vulnerable individuals. Nonetheless, since in other studies the same compound was shown to induce PPI alterations in Wistar rats, our results are also suggestive that genetic differences might be critical for the development of cannabis-induced cognitive disorders.
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Affiliation(s)
- Marco Bortolato
- Department of Neuroscience B.B. Brodie, Center of Excellence Neurobiology of Dependence, University of Cagliari, Cittadella Universitaria, S.S. 554 Km 4,500, 09042, Monserrato, CA, Italy.
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Fernandez-Espejo E, Galan-Rodriguez B. Sensorimotor gating in mice is disrupted after AM404, an anandamide reuptake and degradation inhibitor. Psychopharmacology (Berl) 2004; 175:220-4. [PMID: 15088080 DOI: 10.1007/s00213-004-1851-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2003] [Accepted: 02/19/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE Prepulse inhibition (PPI) represents a normal sensorimotor gating response that is typically impaired in schizophrenic patients. It is known that cannabinoid CB1 agonists reduce sensorimotor gating in rats, suggesting that the CB1 receptor and the cannabinoid system are involved in sensorimotor gating. OBJECTIVE The objective was to study the effects of AM404, an anandamide reuptake and degradation inhibitor, on PPI and startle response in Swiss mice. METHODS. AM404 was injected either acutely (0, 2.5 and 5 mg/kg i.p.) or chronically (5 mg/kg daily, 7 days). The PPI protocol was based on standard methodologies using acoustic stimuli (pulse 120 dB; prepulses 70 dB and 80 dB). SR141716A, a CB1 antagonist, was employed for further confirmation of the involvement of CB1 receptors. RESULTS Acute AM404 (5 mg/kg) disrupted PPI (70-dB prepulse, P<0.05) and enhanced the startle response after the 2.5-mg/kg dose (P<0.01). Chronic AM404 disrupted PPI after both 70-dB (P<0.01) and 80-dB prepulses (P<0.05). These effects were blocked after SR141716A cotreatment. CONCLUSIONS The data indicate that AM404 (5 mg/kg) acts as a psychodysleptic, altering PPI through stimulation of cannabinoid CB1 receptors, pointing to a possible "psychosis-like" state after enhancement of anandamide bioavailability. The startle response was enhanced only following a lower AM404 dose (2.5 mg/kg), indicating that AM404 induced hyperreactivity at a dose that did not affect PPI, further reinforcing a selective disruption of PPI.
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Affiliation(s)
- Emilio Fernandez-Espejo
- Departamento de Fisiologia Medica y Biofisica, Universidad de Sevilla, Av. Sanchez Pizjuan 4, 41009 Sevilla, Spain.
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25
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Oz M, Spivak CE, Lupica CR. The solubilizing detergents, Tween 80 and Triton X-100 non-competitively inhibit α7-nicotinic acetylcholine receptor function in Xenopus oocytes. J Neurosci Methods 2004; 137:167-73. [PMID: 15262057 DOI: 10.1016/j.jneumeth.2004.02.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Revised: 02/13/2004] [Accepted: 02/13/2004] [Indexed: 11/24/2022]
Abstract
Because many studies rely upon detergents to solubilize lipophilic agents such as cannabinoid drugs, we examined the effect of commonly employed detergents on the function of the cloned alpha(7) subunit of the nicotinic ACh receptor. Homomeric alpha(7) receptors were expressed in Xenopus oocytes and the two-microelectrode voltage-clamp technique was used to assess their electrophysiological properties. The detergents Tween 80 and Triton X-100 reversibly inhibited ACh (100 microM)-induced inward currents in a concentration-dependent manner, with IC(50) values of 610 nM and 1.4 microM, respectively. The effects of these detergents were independent of membrane potential, and they were not mediated by endogenous Ca(2+)-dependent Cl(-) channels, since they were unaffected by intracellularly injected BAPTA, and recorded in Ca(2+)-free bathing solution containing 2 mM Ba(2+). Both detergents also decreased the maximal effect of ACh, without significantly affecting its EC(50), indicating a non-competitive interaction with the nACh alpha(7) receptors. In contrast to the effects of these detergents, we found that cholic acid (10 microM), DMSO (10 microM) and Tocrisol (0.01% v/v) did not cause a significant effect on nicotinic responses. In conclusion, we demonstrate that the detergents Tween 80 and Triton X-100 are potent inhibitors of neuronal nACh alpha(7) receptors expressed in Xenopus oocytes, and we suggest that studies utilizing these detergents to solubilize lipophilic drugs should be scrutinized for such effects.
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Affiliation(s)
- Murat Oz
- National Institute on Drug Abuse, NIH/DHHS, Intramural Research Program, Cellular Neurobiology Branch, Cellular Neurophysiology Section, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA
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Quednow BB, Kühn KU, Hoenig K, Maier W, Wagner M. Prepulse inhibition and habituation of acoustic startle response in male MDMA ('ecstasy') users, cannabis users, and healthy controls. Neuropsychopharmacology 2004; 29:982-90. [PMID: 14970829 DOI: 10.1038/sj.npp.1300396] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chronic administration of 3,4-methylenedioxymethamphetamine (MDMA) is associated with long-term depletion of serotonin (5-HT) and loss of 5-HT axons in the brains of rodents and nonhuman primates. Despite the broad database concerning the selective serotonergic neurotoxicity of recreational MDMA consumption by humans, controversy still exists with respect to the question of whether the well-known functional consequences of these neurotoxic effects, such as memory impairment, were caused by chronic 5-HT deficiency. Habituation and prepulse inhibition (PPI) of the acoustic startle response (ASR) can be used as a marker of central serotonergic functioning in rodents and humans. Thus, we investigated the functional status of the central serotonergic system in chronic but abstinent MDMA users by measuring PPI and habituation of ASR. PPI and habituation of ASR were measured in three groups. The first group (MDMA group) included 20 male drug-free chronic users of MDMA; the second group (cannabis group) consisted of 20 male drug-free chronic users of cannabis; and the third group (healthy controls) comprised 20 male participants with no history of illicit drug use. Analysis revealed significantly increased PPI of MDMA users compared to those of cannabis users and healthy controls. Cannabis users and healthy controls showed comparable patterns of PPI. There were no differences in habituation among the three groups. These results suggest that the functional consequences of chronic MDMA use may be explained by 5-HT receptor changes rather than by a chronic 5-HT deficiency condition. Use of cannabis does not lead to alterations of amplitude, habituation, or PPI of ASR.
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Schneider M, Koch M. Chronic pubertal, but not adult chronic cannabinoid treatment impairs sensorimotor gating, recognition memory, and the performance in a progressive ratio task in adult rats. Neuropsychopharmacology 2003; 28:1760-9. [PMID: 12888772 DOI: 10.1038/sj.npp.1300225] [Citation(s) in RCA: 305] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
There is evidence from studies in humans and animals that a vulnerable period for chronic cannabinoid administration exists during certain phases of development. The present study tested the hypothesis that long-lasting interference of cannabinoids with the developing endogenous cannabinoid system during puberty causes persistent behavioral alterations in adult rats. Chronic treatment with the synthetic cannabinoid agonist WIN 55,212-2 (WIN) (1.2 mg/kg) or vehicle was extended over 25 days either throughout the rats' puberty or for a similar time period in adult rats. The rats received 20 injections intraperitoneally (i.p.), which were not delivered regularly. Adult rats were tested for object recognition memory, performance in a progressive ratio (PR) operant behavior task, locomotor activity, and prepulse inhibition (PPI) of the acoustic startle response (ASR). PPI was significantly disrupted only by chronic peripubertal cannabinoid treatment. This long-lasting PPI deficit was reversed by the acute administration of the dopamine antagonist haloperidol. Furthermore, we found deficits in recognition memory of pubertal-treated rats and these animals showed lower break points in a PR schedule, whereas food preference and locomotion were not affected. Adult chronic cannabinoid treatment had no effect on the behaviors tested. Therefore, we conclude that puberty in rats is a vulnerable period with respect to the adverse effects of cannabinoid treatment. Since PPI deficits, object recognition memory impairments, and anhedonia/avolition are among the endophenotypes of schizophrenia, we propose chronic cannabinoid administration during pubertal development as an animal model for some aspects of the etiology of schizophrenia.
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Affiliation(s)
- Miriam Schneider
- Brain Research Institute, Department of Neuropharmacology, University of Bremen, Bremen, Germany.
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