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Montiel-Herrera F, Batanero-Geraldo A, López JC, Vargas JP, Quintero E, Díaz E. Effects of acute and chronic methylphenidate on prepulse inhibition: A sex difference study in Wistar rats. Physiol Behav 2024; 278:114526. [PMID: 38531426 DOI: 10.1016/j.physbeh.2024.114526] [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: 01/25/2024] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/28/2024]
Abstract
BACKGROUND The utilization of methylphenidate (MPH) is experiencing a notable surge within the adult population. This growth can be attributed to two key factors: its recreational and cognitive enhancement purposes, as well as the rising prevalence of ADHD diagnoses within this population. This study examined acute and chronic oral MPH effects on attention in male and female Wistar rats. To this end, we used a prepulse inhibition (PPI) task, which is widely used to assess psychoactive drug effects in both humans and rodents. This task allowed us to evaluate changes in attention by analyzing sensorimotor gating associated with stimulus selection process. METHODS Animals were administered a clinically relevant dose of MPH (5 mg/kg) daily for seven days. The estrous cycle phases of the female rats were measured during behavioral sessions. The PPI task was conducted 20 min after drug administration on day 1 (acute), day 7 (chronic), and 48 h post-treatment. RESULTS Results indicated that both acute and chronic MPH treatment impaired PPI expression in male rats, but not in female rats, regardless of their estrous cycle phase. Furthermore, a differential effect of chronic MPH treatment on the PPI task was found in male rats. Specifically, on the seventh treatment day, the PPI effect was observed when animals undertook the PPI task for the first time but was impaired in those animals in which the initial PPI session occurred under the acute influence of the drug (day 1). CONCLUSIONS These findings suggest that the impact of MPH on sensorimotor gating responses may vary based on sex and task experience, possibly leading to state-dependent effects in healthy individuals.
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Affiliation(s)
- F Montiel-Herrera
- Laboratory of Animal Behavior and Neuroscience, Department of Experimental Psychology, University of Seville, Seville, Spain
| | - A Batanero-Geraldo
- Laboratory of Animal Behavior and Neuroscience, Department of Experimental Psychology, University of Seville, Seville, Spain
| | - J C López
- Laboratory of Animal Behavior and Neuroscience, Department of Experimental Psychology, University of Seville, Seville, Spain
| | - J P Vargas
- Laboratory of Animal Behavior and Neuroscience, Department of Experimental Psychology, University of Seville, Seville, Spain
| | - E Quintero
- Laboratory of Animal Behavior and Neuroscience, Department of Experimental Psychology, University of Seville, Seville, Spain
| | - E Díaz
- Laboratory of Animal Behavior and Neuroscience, Department of Experimental Psychology, University of Seville, Seville, Spain.
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López-Taboada I, Sal-Sarria S, Vallejo G, Coto-Montes A, Conejo NM, González-Pardo H. Sexual dimorphism in spatial learning and brain metabolism after exposure to a western diet and early life stress in rats. Physiol Behav 2022; 257:113969. [PMID: 36181786 DOI: 10.1016/j.physbeh.2022.113969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/17/2022] [Accepted: 09/22/2022] [Indexed: 01/06/2023]
Abstract
Prolonged daily intake of Western-type diet rich in saturated fats and sugars, and exposure to early life stress have been independently linked to impaired neurodevelopment and behaviour in animal models. However, sex-specific effects of both environmental factors combined on spatial learning and memory, behavioural flexibility, and brain oxidative capacity have still not been addressed. The current study aimed to evaluate the impact of maternal and postnatal exposure to a high-fat and high-sugar diet (HFS), and exposure to early life stress by maternal separation in adult male and female Wistar rats. For this purpose, spatial learning and memory and behavioural flexibility were evaluated in the Morris water maze, and regional brain oxidative capacity and oxidative stress levels were measured in the hippocampus and medial prefrontal cortex. Spatial memory, regional brain oxidative metabolism, and levels of oxidative stress differed between females and males, suggesting sexual dimorphism in the effects of a HFS diet and early life stress. Males fed the HFS diet performed better than all other experimental groups independently of early life stress exposure. However, behavioural flexibility evaluated in the spatial reversal leaning task was impaired in males fed the HFS diet. In addition, exposure to maternal separation or the HFS diet increased the metabolic capacity of the prefrontal cortex and dorsal hippocampus in males and females. Levels of oxidative stress measured in the latter brain regions were also increased in groups fed the HFS diet, but maternal separation seemed to dampen regional brain oxidative stress levels. Therefore, these results suggest a compensatory effect resulting from the interaction between prolonged exposure to a HFS diet and early life stress.
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Affiliation(s)
- Isabel López-Taboada
- Laboratory of Neuroscience, Department of Psychology, Faculty of Psychology, University of Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain; Institute of Neurosciences of the Principality of Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Av. del Hospital Universitario s/n, 33011 Oviedo, Spain
| | - Saúl Sal-Sarria
- Laboratory of Neuroscience, Department of Psychology, Faculty of Psychology, University of Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain; Institute of Neurosciences of the Principality of Asturias (INEUROPA), Oviedo, Spain
| | - Guillermo Vallejo
- Methodology area, Department of Psychology, Faculty of Psychology, University of Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain
| | - Ana Coto-Montes
- Institute of Neurosciences of the Principality of Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Av. del Hospital Universitario s/n, 33011 Oviedo, Spain; Department of Morphology and Cell Biology, Faculty of Medicine, University of Oviedo, Julián Clavería s/n, 33006 Oviedo, Spain
| | - Nélida M Conejo
- Laboratory of Neuroscience, Department of Psychology, Faculty of Psychology, University of Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain; Institute of Neurosciences of the Principality of Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Av. del Hospital Universitario s/n, 33011 Oviedo, Spain.
| | - Héctor González-Pardo
- Laboratory of Neuroscience, Department of Psychology, Faculty of Psychology, University of Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain; Institute of Neurosciences of the Principality of Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Av. del Hospital Universitario s/n, 33011 Oviedo, Spain
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Polli FS, Kohlmeier KA. Prenatal nicotine alters development of the laterodorsal tegmentum: Possible role for attention-deficit/hyperactivity disorder and drug dependence. World J Psychiatry 2022; 12:212-235. [PMID: 35317337 PMCID: PMC8900586 DOI: 10.5498/wjp.v12.i2.212] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 08/07/2021] [Accepted: 01/14/2022] [Indexed: 02/06/2023] Open
Abstract
As we cycle between the states of wakefulness and sleep, a bilateral cholinergic nucleus in the pontine brain stem, the laterodorsal tegmentum (LDT), plays a critical role in controlling salience processing, attention, behavioral arousal, and electrophysiological signatures of the sub- and microstates of sleep. Disorders involving abnormal alterations in behavioral and motivated states, such as drug dependence, likely involve dysfunctions in LDT signaling. In addition, as the LDT exhibits connectivity with the thalamus and mesocortical circuits, as well as receives direct, excitatory input from the prefrontal cortex, a role for the LDT in cognitive symptoms characterizing attention-deficit/hyperactivity disorder (ADHD) including impulsivity, inflexibility, and dysfunctions of attention is suggested. Prenatal nicotine exposure (PNE) is associated with a higher risk for later life development of drug dependence and ADHD, suggesting alteration in development of brain regions involved in these behaviors. PNE has been shown to alter glutamate and cholinergic signaling within the LDT. As glutamate and acetylcholine are major excitatory mediators, these alterations would likely alter excitatory output to target regions in limbic motivational circuits and to thalamic and cortical networks mediating executive control. Further, PNE alters neuronal development and transmission within prefrontal cortex and limbic areas that send input to the LDT, which would compound effects of differential processing within the PNE LDT. When taken together, alterations in signaling in the LDT are likely to play a role in negative behavioral outcomes seen in PNE individuals, including a heightened risk of drug dependence and ADHD behaviors.
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Affiliation(s)
- Filip S Polli
- Drug Design and Pharmacology, University of Copenhagen, Copenhagen 2100, Denmark
| | - Kristi A Kohlmeier
- Drug Design and Pharmacology, University of Copenhagen, Copenhagen 2100, Denmark
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miR-124 dosage regulates prefrontal cortex function by dopaminergic modulation. Sci Rep 2019; 9:3445. [PMID: 30837489 PMCID: PMC6401137 DOI: 10.1038/s41598-019-38910-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/07/2019] [Indexed: 01/13/2023] Open
Abstract
MicroRNA-124 (miR-124) is evolutionarily highly conserved among species and one of the most abundantly expressed miRNAs in the developing and mature central nervous system (CNS). Previous studies reported that miR-124 plays a role in CNS development, such as neuronal differentiation, maturation, and survival. However, the role of miR-124 in normal brain function has not yet been revealed. Here, we subjected miR-124-1+/− mice, to a comprehensive behavioral battery. We found that miR-124-1+/− mice showed impaired prepulse inhibition (PPI), methamphetamine-induced hyperactivity, and social deficits. Whole cell recordings using prefrontal cortex (PFC) slices showed enhanced synaptic transmission in layer 5 pyramidal cells in the miR-124-1+/− PFC. Based on the results of behavioral and electrophysiological analysis, we focused on genes involved in the dopaminergic system and identified a significant increase of Drd2 expression level in the miR-124-1+/− PFC. Overexpression or knockdown of Drd2 in the control or miR-124-1+/− PFC demonstrates that aberrant Drd2 signaling leads to impaired PPI. Furthermore, we identified that expression of glucocorticoid receptor gene Nr3c1, which enhances Drd2 expression, increased in the miR-124-1+/− PFC. Taken together, the current study suggests that miR-124 dosage modulates PFC function through repressing the Drd2 pathway, suggesting a critical role of miR-124 in normal PFC function.
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Pérez-Díaz F, Díaz E, Sánchez N, Vargas JP, Pearce JM, López JC. Different involvement of medial prefrontal cortex and dorso-lateral striatum in automatic and controlled processing of a future conditioned stimulus. PLoS One 2017; 12:e0189630. [PMID: 29240804 PMCID: PMC5730208 DOI: 10.1371/journal.pone.0189630] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/29/2017] [Indexed: 11/30/2022] Open
Abstract
Recent studies support the idea that stimulus processing in latent inhibition can vary during the course of preexposure. Controlled attentional mechanisms are said to be important in the early stages of preexposure, while in later stages animals adopt automatic processing of the stimulus to be used for conditioning. Given this distinction, it is possible that both types of processing are governed by different neural systems, affecting differentially the retrieval of information about the stimulus. In the present study we tested if a lesion to the dorso-lateral striatum or to the medial prefrontal cortex has a selective effect on exposure to the future conditioned stimulus (CS). With this aim, animals received different amounts of exposure to the future CS. The results showed that a lesion to the medial prefrontal cortex enhanced latent inhibition in animals receiving limited preexposure to the CS, but had no effect in animals receiving extended preexposure to the CS. The lesion of the dorso-lateral striatum produced a decrease in latent inhibition, but only in animals with an extended exposure to the future conditioned stimulus. These results suggest that the dorsal striatum and medial prefrontal cortex play essential roles in controlled and automatic processes. Automatic attentional processes appear to be impaired by a lesion to the dorso-lateral striatum and facilitated by a lesion to the prefrontal cortex.
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Affiliation(s)
- Francisco Pérez-Díaz
- Animal Behav & Neurosci Lab, Dpt. Psicología Experimental, Universidad de Sevilla, c/ Camilo Jose Cela s/n, Seville, Spain
| | - Estrella Díaz
- Animal Behav & Neurosci Lab, Dpt. Psicología Experimental, Universidad de Sevilla, c/ Camilo Jose Cela s/n, Seville, Spain
| | - Natividad Sánchez
- Animal Behav & Neurosci Lab, Dpt. Psicología Experimental, Universidad de Sevilla, c/ Camilo Jose Cela s/n, Seville, Spain
| | - Juan Pedro Vargas
- Animal Behav & Neurosci Lab, Dpt. Psicología Experimental, Universidad de Sevilla, c/ Camilo Jose Cela s/n, Seville, Spain
| | - John M. Pearce
- School of Psychology, Cardiff University, Cardiff, Wales, United Kingdom
- School of Psychology, University of Sydney, Sydney, Australia
| | - Juan Carlos López
- Animal Behav & Neurosci Lab, Dpt. Psicología Experimental, Universidad de Sevilla, c/ Camilo Jose Cela s/n, Seville, Spain
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Alkam T, Mamiya T, Kimura N, Yoshida A, Kihara D, Tsunoda Y, Aoyama Y, Hiramatsu M, Kim HC, Nabeshima T. Prenatal nicotine exposure decreases the release of dopamine in the medial frontal cortex and induces atomoxetine-responsive neurobehavioral deficits in mice. Psychopharmacology (Berl) 2017; 234:1853-1869. [PMID: 28332006 DOI: 10.1007/s00213-017-4591-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/05/2017] [Indexed: 02/06/2023]
Abstract
Increased risk of attention-deficit/hyperactivity disorder (AD/HD) is partly associated with the early developmental exposure to nicotine in tobacco smoke. Emerging reports link tobacco smoke exposure or prenatal nicotine exposure (PNE) with AD/HD-like behaviors in rodent models. We have previously reported that PNE induces cognitive behavioral deficits in offspring and decreases the contents of dopamine (DA) and its turnover in the prefrontal cortex (PFC) of offspring It is well known that the dysfunction of DAergic system in the brain is one of the core factors in the pathophysiology of AD/HD. Therefore, we examined whether the effects of PNE on the DAergic system underlie the AD/HD-related behavioral changes in mouse offspring. PNE reduced the release of DA in the medial PFC (mPFC) in mouse offspring. PNE reduced the number of tyrosine hydroxylase (TH)-positive varicosities in the mPFC and in the core as well as the shell of nucleus accumbens, but not in the striatum. PNE also induced behavioral deficits in cliff avoidance, object-based attention, and sensorimotor gating in offspring. These behavioral deficits were attenuated by acute treatment with atomoxetine (3 mg/kg, s.c.) or partially attenuated by acute treatment with MPH (1 mg/kg, s.c.). Taken together, our findings support the notion that PNE induces neurobehavioral abnormalities in mouse offspring by disrupting the DAergic system and improve our understanding about the incidence of AD/HD in children whose mothers were exposed to nicotine during their pregnancy.
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Affiliation(s)
- Tursun Alkam
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, USA
| | - Takayoshi Mamiya
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
- Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan
| | - Nami Kimura
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Aya Yoshida
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Daisuke Kihara
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Yuki Tsunoda
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Yuki Aoyama
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Masayuki Hiramatsu
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
- Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, South Korea
| | - Toshitaka Nabeshima
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan.
- Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan.
- Advanced Diagnostic System Research Laboratory, Graduate School of Health Sciences, Fujita Health University, Toyoake, Aichi, 470-1192, Japan.
- Aino University, Ibaraki, Japan.
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Managò F, Mereu M, Mastwal S, Mastrogiacomo R, Scheggia D, Emanuele M, De Luca MA, Weinberger DR, Wang KH, Papaleo F. Genetic Disruption of Arc/Arg3.1 in Mice Causes Alterations in Dopamine and Neurobehavioral Phenotypes Related to Schizophrenia. Cell Rep 2016; 16:2116-2128. [PMID: 27524619 DOI: 10.1016/j.celrep.2016.07.044] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 06/29/2016] [Accepted: 07/16/2016] [Indexed: 01/08/2023] Open
Abstract
Human genetic studies have recently suggested that the postsynaptic activity-regulated cytoskeleton-associated protein (Arc) complex is a convergence signal for several genes implicated in schizophrenia. However, the functional significance of Arc in schizophrenia-related neurobehavioral phenotypes and brain circuits is unclear. Here, we find that, consistent with schizophrenia-related phenotypes, disruption of Arc in mice produces deficits in sensorimotor gating, cognitive functions, social behaviors, and amphetamine-induced psychomotor responses. Furthermore, genetic disruption of Arc leads to concomitant hypoactive mesocortical and hyperactive mesostriatal dopamine pathways. Application of a D1 agonist to the prefrontal cortex or a D2 antagonist in the ventral striatum rescues Arc-dependent cognitive or psychomotor abnormalities, respectively. Our findings demonstrate a role for Arc in the regulation of dopaminergic neurotransmission and related behaviors. The results also provide initial biological support implicating Arc in dopaminergic and behavioral abnormalities related to schizophrenia.
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Affiliation(s)
- Francesca Managò
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Maddalena Mereu
- Dipartimento di Scienze del Farmaco, Università degli Studi di Padova, Largo Meneghetti 2, 35131 Padova, Italy
| | - Surjeet Mastwal
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, Bethesda, MD 20892, USA
| | - Rosa Mastrogiacomo
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Diego Scheggia
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Marco Emanuele
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Maria A De Luca
- Department of Biomedical Sciences, Università di Cagliari, 09124 Cagliari, Italy
| | - Daniel R Weinberger
- Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, MD 21205, USA; Departments of Psychiatry, Neurology, and Neuroscience and McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Kuan Hong Wang
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, Bethesda, MD 20892, USA.
| | - Francesco Papaleo
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy.
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Eells JB, Varela-Stokes A, Guo-Ross SX, Kummari E, Smith HM, Cox AD, Lindsay DS. Chronic Toxoplasma gondii in Nurr1-null heterozygous mice exacerbates elevated open field activity. PLoS One 2015; 10:e0119280. [PMID: 25855987 PMCID: PMC4391871 DOI: 10.1371/journal.pone.0119280] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/20/2015] [Indexed: 12/19/2022] Open
Abstract
Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population) and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%), genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/-) mice and wild-type (+/+) mice were evaluate using an emergence test, activity in an open field and with a novel object, response to bobcat urine and prepulse inhibition of the acoustic startle response (PPI) prior to and 6 weeks after infection with T. gondii. In the emergence test, T. gondii infection significantly decreased the amount of time spent in the cylinder. Toxoplasma gondii infection significantly elevated open field activity in both +/+ and +/- mice but this increase was significantly exacerbated in +/- mice. T. gondii infection reduced PPI in male +/- mice but this was not statistically significant. Aversion to bobcat urine was abolished by T. gondii infection in +/+ mice. In female +/- mice, aversion to bobcat urine remained after T. gondii infection while the male +/- mice showed no aversion to bobcat urine. Antibody titers of infected mice were a critical variable associated with changes in open field activity, such that an inverted U shaped relationship existed between antibody titers and the percent change in open field activity with a significant increase in activity at low and medium antibody titers but no effect at high antibody titers. These data demonstrate that the Nurr1 +/- genotype predisposes mice to T. gondii-induced alterations in behaviors that involve dopamine neurotransmission and are associated with symptoms of schizophrenia. We propose that these alterations in murine behavior were due to further exacerbation of the altered dopamine neurotransmission in Nurr1 +/- mice.
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Affiliation(s)
- Jeffrey B. Eells
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
- * E-mail:
| | - Andrea Varela-Stokes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Shirley X. Guo-Ross
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Evangel Kummari
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Holly M. Smith
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Arin D. Cox
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - David S. Lindsay
- Department of Biomedical Sciences & Pathobiology, Virginia–Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States of America
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Cassaday HJ, Nelson AJD, Pezze MA. From attention to memory along the dorsal-ventral axis of the medial prefrontal cortex: some methodological considerations. Front Syst Neurosci 2014; 8:160. [PMID: 25249948 PMCID: PMC4157611 DOI: 10.3389/fnsys.2014.00160] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 08/15/2014] [Indexed: 12/16/2022] Open
Abstract
Distinctions along the dorsal-ventral axis of medial prefrontal cortex (mPFC), between anterior cingulate (AC), prelimbic (PL), and infralimbic (IL) sub-regions, have been proposed on a variety of neuroanatomical and neurophysiological grounds. Conventional lesion approaches (as well as some electrophysiological studies) have shown that these distinctions relate to function in that a number behavioral dissociations have been demonstrated, particularly using rodent models of attention, learning, and memory. For example, there is evidence to suggest that AC has a relatively greater role in attention, whereas IL is more involved in executive function. However, the well-established methods of behavioral neuroscience have the limitation that neuromodulation is not addressed. The neurotoxin 6-hydroxydopamine has been used to deplete dopamine (DA) in mPFC sub-regions, but these lesions are not selective anatomically and noradrenalin is typically also depleted. Microinfusion of drugs through indwelling cannulae provides an alternative approach, to address the role of neuromodulation and moreover that of specific receptor subtypes within mPFC sub-regions, but the effects of such treatments cannot be assumed to be anatomically restricted either. New methodological approaches to the functional delineation of the role of mPFC in attention, learning and memory will also be considered. Taken in isolation, the conventional lesion methods which have been a first line of approach may suggest that a particular mPFC sub-region is not necessary for a particular aspect of function. However, this does not exclude a neuromodulatory role and more neuropsychopharmacological approaches are needed to explain some of the apparent inconsistencies in the results.
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Affiliation(s)
| | - Andrew J D Nelson
- School of Psychology, University of Nottingham Nottingham, UK ; School of Psychology, Cardiff University Cardiff, UK
| | - Marie A Pezze
- School of Psychology, University of Nottingham Nottingham, UK
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Piccart E, De Backer JF, Gall D, Lambot L, Raes A, Vanhoof G, Schiffmann S, D’Hooge R. Genetic deletion of PDE10A selectively impairs incentive salience attribution and decreases medium spiny neuron excitability. Behav Brain Res 2014; 268:48-54. [DOI: 10.1016/j.bbr.2014.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 03/02/2014] [Accepted: 03/12/2014] [Indexed: 01/04/2023]
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Hayen A, Meese-Tamuri S, Gates A, Ito R. Opposing roles of prelimbic and infralimbic dopamine in conditioned cue and place preference. Psychopharmacology (Berl) 2014; 231:2483-92. [PMID: 24429871 PMCID: PMC4039995 DOI: 10.1007/s00213-013-3414-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 12/16/2013] [Indexed: 11/29/2022]
Abstract
RATIONALE Increasing evidence points to the prelimbic (PL) and infralimbic (IL) cortices of the medial prefrontal cortex (mPFC) and their dopaminergic innervations subserving opposing roles in the regulation of instrumental behavior. However, it is at present unclear if they hold similar roles in the regulation of Pavlovian learning. OBJECTIVE The present study investigated the role of the dopaminergic innervations of the PL and IL in the modulation of Pavlovian appetitive cue and place conditioning, previously shown to be dependent on the basolateral amygdala and hippocampus, respectively. METHODS Rats received preconditioning microinfusions of D-amphetamine, cis-flupenthixol, or vehicle solution directly into the PL or IL and were trained to simultaneously acquire conditioned cue and place preference in a radial maze. RESULTS Preconditioning blockade of dopamine neurotransmission in the PL and amphetamine microinfusions in the IL had the same effect of attenuating place conditioning. In contrast, place conditioning remained intact following preconditioning amphetamine microinfusions in the PL and dopamine receptor blockade in the IL. Instead, conditioned cue preference was attenuated following IL dopamine receptor blockade. CONCLUSION These data indicate that PL dopaminergic mechanisms are critical for the acquisition of appetitive place learning, while IL dopamine may oppose the influence of PL dopamine upon hippocampal-dependent learning. Furthermore, they implicate a functional reciprocity between mPFC and associated subregions of the nucleus accumbens in the regulation of limbic information processing.
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Affiliation(s)
- Anja Hayen
- Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, OX1 3UD UK
| | - Saira Meese-Tamuri
- Department of Psychology, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4 Canada
| | - Amy Gates
- Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, OX1 3UD UK
| | - Rutsuko Ito
- Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, OX1 3UD UK
- Department of Psychology, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4 Canada
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Meyer F, Louilot A. Consequences at adulthood of transient inactivation of the parahippocampal and prefrontal regions during early development: new insights from a disconnection animal model for schizophrenia. Front Behav Neurosci 2014; 8:118. [PMID: 24778609 PMCID: PMC3985036 DOI: 10.3389/fnbeh.2014.00118] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 03/21/2014] [Indexed: 11/16/2022] Open
Abstract
The psychic disintegration characteristic of schizophrenia is thought to result from a defective connectivity, of neurodevelopmental origin, between several integrative brain regions. The parahippocampal region and the prefrontal cortex are described as the main regions affected in schizophrenia. Interestingly, latent inhibition (LI) has been found to be reduced in patients with schizophrenia, and the existence of a dopaminergic dysfunction is also generally well accepted in this disorder. In the present review, we have integrated behavioral and neurochemical data obtained in a LI protocol involving adult rats subjected to neonatal functional inactivation of the entorhinal cortex, the ventral subiculum or the prefrontal cortex. The data discussed suggest a subtle and transient functional blockade during early development of the aforementioned brain regions is sufficient to induce schizophrenia-related behavioral and dopaminergic abnormalities in adulthood. In summary, these results support the view that our conceptual and methodological approach, based on functional disconnections, is valid for modeling some aspects of the pathophysiology of schizophrenia from a neurodevelopmental perspective.
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Affiliation(s)
- Francisca Meyer
- 1Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Nijmegen, Netherlands
| | - Alain Louilot
- 2INSERM U 1114, Faculty of Medicine, FMTS, University of Strasbourg Strasbourg, France
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13
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De Luca MA. Habituation of the responsiveness of mesolimbic and mesocortical dopamine transmission to taste stimuli. Front Integr Neurosci 2014; 8:21. [PMID: 24624065 PMCID: PMC3941202 DOI: 10.3389/fnint.2014.00021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 02/13/2014] [Indexed: 11/15/2022] Open
Abstract
The presentation of novel, remarkable, and unpredictable tastes increases dopamine (DA) transmission in different DA terminal areas such as the nucleus accumbens (NAc) shell and core and the medial prefrontal cortex (mPFC), as estimated by in vivo microdialysis studies in rats. This effect undergoes adaptive regulation, as there is a decrease in DA responsiveness after a single pre-exposure to the same taste. This phenomenon termed habituation has been described as peculiar to NAc shell but not to NAc core and mPFC DA transmission. On this basis, it has been proposed that mPFC DA codes for generic motivational stimulus value and, together with the NAc core DA, is more consistent with a role in the expression of motivation. Conversely, NAc shell DA is specifically activated by unfamiliar or novel taste stimuli and rewards, and might serve to associate the sensory properties of the rewarding stimulus with its biological effect (Bassareo etal., 2002; Di Chiara etal., 2004). Notably, habituation of the DA response to intraoral sweet or bitter tastes is not associated with a reduction in hedonic or aversive taste reactions, thus indicating that habituation is unrelated to satiety-induced hedonic devaluation and that it is not influenced by DA alteration or depletion. This mini-review describes specific circumstances of disruption of the habituation of NAc shell DA responsiveness (De Luca etal., 2011; Bimpisidis etal., 2013). In particular, we observed an abolishment of NAc shell DA habituation to chocolate (sweet taste) by morphine sensitization and mPFC 6-hydroxy-dopamine hydrochloride (6-OHDA) lesion. Moreover, morphine sensitization was associated with the appearance of the habituation in the mPFC, and with an increased and delayed response of NAc core DA to taste in naive rats, but not in pre-exposed animals. The results here described shed light on the mechanism of the habituation phenomenon of mesolimbic and mesocortical DA transmission, and its putative role as a marker of cortical dysfunction in specific conditions such as addiction.
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Affiliation(s)
- Maria A De Luca
- Department of Biomedical Sciences, Neuropsychopharmacology Section, University of Cagliari Cagliari, Italy ; National Institute of Neuroscience, University of Cagliari Cagliari, Italy
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Reichelt AC, Lee JLC. Memory reconsolidation in aversive and appetitive settings. Front Behav Neurosci 2013; 7:118. [PMID: 24058336 PMCID: PMC3766793 DOI: 10.3389/fnbeh.2013.00118] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/20/2013] [Indexed: 11/16/2022] Open
Abstract
Memory reconsolidation has been observed across species and in a number of behavioral paradigms. The majority of memory reconsolidation studies have been carried out in Pavlovian fear conditioning and other aversive memory settings, with potential implications for the treatment of post-traumatic stress disorder. However, there is a growing literature on memory reconsolidation in appetitive reward-related memory paradigms, including translational models of drug addiction. While there appears to be substantial similarity in the basic phenomenon and underlying mechanisms of memory reconsolidation across unconditioned stimulus valence, there are also notable discrepancies. These arise both when comparing aversive to appetitive paradigms and also across different paradigms within the same valence of memory. We review the demonstration of memory reconsolidation across different aversive and appetitive memory paradigms, the commonalities and differences in underlying mechanisms and the conditions under which each memory undergoes reconsolidation. We focus particularly on whether principles derived from the aversive literature are applicable to appetitive settings, and also whether the expanding literature in appetitive paradigms is informative for fear memory reconsolidation.
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Affiliation(s)
- Amy C Reichelt
- School of Psychology, University of Birmingham Birmingham, UK
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15
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Abstract
Drugs that induce psychosis, such as D-amphetamine (AMP), and those that alleviate it, such as antipsychotics, are suggested to exert behavioral effects via dopamine receptor D2 (D2). All antipsychotic drugs are D2 antagonists, but D2 antagonism underlies the severe and debilitating side effects of these drugs; it is therefore important to know whether D2 is necessary for their behavioral effects. Using D2-null mice (Drd2-/-), we first investigated whether D2 is required for AMP disruption of latent inhibition (LI). LI is a process of learning to ignore irrelevant stimuli. Disruption of LI by AMP models impaired attention and abnormal salience allocation consequent to dysregulated dopamine relevant to schizophrenia. AMP disruption of LI was seen in both wild-type (WT) and Drd2-/-. This was in contrast to AMP-induced locomotor hyperactivity, which was reduced in Drd2-/-. AMP disruption of LI was attenuated in mice lacking dopamine receptor D1 (Drd1-/-), suggesting that D1 may play a role in AMP disruption of LI. Further supporting this possibility, we found that D1 antagonist SKF83566 attenuated AMP disruption of LI in WT. Remarkably, both haloperidol and clozapine attenuated AMP disruption of LI in Drd2-/-. This demonstrates that antipsychotic drugs can attenuate AMP disruption of learning to ignore irrelevant stimuli in the absence of D2 receptors. Data suggest that D2 is not essential either for AMP to disrupt or for antipsychotic drugs to reverse AMP disruption of learning to ignore irrelevant stimuli and further that D1 merits investigation in the mediation of AMP disruption of these processes.
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Bimpisidis Z, De Luca MA, Pisanu A, Di Chiara G. Lesion of medial prefrontal dopamine terminals abolishes habituation of accumbens shell dopamine responsiveness to taste stimuli. Eur J Neurosci 2012; 37:613-22. [PMID: 23216547 DOI: 10.1111/ejn.12068] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/25/2012] [Accepted: 10/26/2012] [Indexed: 11/28/2022]
Abstract
Taste stimuli increase extracellular dopamine (DA) in the nucleus accumbens (NAc) and in the medial prefrontal cortex (mPFC). This effect shows single-trial habituation in NAc shell but not in core or in mPFC. Morphine sensitization abolishes habituation of DA responsiveness in NAc shell but induces it in mPFC. These observations support the hypothesis of an inhibitory influence of mPFC DA on NAc DA. To test this hypothesis, we used in vivo microdialysis to investigate the effect of mPFC 6-hydroxy-dopamine (6-OHDA) lesions on the NAc DA responsiveness to taste stimuli. 6-OHDA was infused bilaterally in the mPFC of rats implanted with guide cannulae. After 1 week, rats were implanted with an intraoral catheter, microdialysis probes were inserted into the guide cannulae, and dialysate DA was monitored in NAc shell/core after intraoral chocolate. 6-OHDA infusion reduced tissue DA in the mPFC by 75%. Tyrosine hydroxylase immunohistochemistry showed that lesions were confined to the mPFC. mPFC 6-OHDA lesion did not affect the NAc shell DA responsiveness to chocolate in naive rats but abolished habituation in rats pre-exposed to the taste. In the NAc core, mPFC lesion potentiated, delayed and prolonged the stimulatory DA response to taste but failed to affect DA in pre-exposed rats. Behavioural taste reactions and motor activity were not affected. The results indicate a top-down control of NAc DA by mPFC and a reciprocal relationship between DA transmission in these two areas. Moreover, habituation of DA responsiveness in the NAc shell is dependent upon an intact DA input to the mPFC.
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Affiliation(s)
- Zisis Bimpisidis
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
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17
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Brown RW, Maple AM, Perna MK, Sheppard AB, Cope ZA, Kostrzewa RM. Schizophrenia and Substance Abuse Comorbidity: Nicotine Addiction and the Neonatal Quinpirole Model. Dev Neurosci 2012; 34:140-51. [DOI: 10.1159/000338830] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 04/12/2012] [Indexed: 01/06/2023] Open
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Salum C, Issy AC, Brandão ML, Guimarães FS, Bel EAD. Nitric oxide modulates dopaminergic regulation of prepulse inhibition in the basolateral amygdala. J Psychopharmacol 2011; 25:1639-48. [PMID: 20837567 DOI: 10.1177/0269881110379282] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Systemic injection of the nitric oxide (NO) synthase inhibitor N(G)-nitro-L-arginine (LNO) prevents the disruptive effect of amphetamine (Amph) on prepulse inhibition (PPI), a sensorimotor gating model in which the amplitude of the acoustic startle response (ASR) to a startling sound (pulse) is reduced when preceded immediately by a weaker stimulus (prepulse). Given that dopamine (DA) projections to the basolateral amygdala (BLA) are involved in the control of information processing, our aim was to investigate if intra-BLA administration of LNO would modify the disruption caused by the DA agonists, Amph, apomorphine (Apo) and quinpirole (QNP), on PPI. Male Wistar rats received bilateral intra-BLA microinjections (0.2 µL/min/side) of combined treatments (saline or LNO 11 µg followed by saline, QNP 3 µg, Apo 10 µg or Amph 30 µg). PPI was disrupted by intra-BLA Apo, QNP or Amph but not by LNO. Prior bilateral intra-BLA injection of LNO prevented the Apo- and QNP-induced disruption of PPI but did not affect that caused by Amph. APO- or QNP-induced increases in ASR to prepulse + pulse were also restored by LNO. Since local inhibition of NO formation affected the effects of direct, but not indirect, DA agonists, the results suggest that this modulation is not occurring at the level of DA release but may involve complex interactions with other neurotransmitter systems.
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Affiliation(s)
- C Salum
- Centro de Matemática, Computação e Cognição, Núcleo de Cognição e Sistemas Complexos, Universidade Federal do ABC, São Paulo, Brazil.
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Brosda J, Dietz F, Koch M. Impairment of cognitive performance after reelin knockdown in the medial prefrontal cortex of pubertal or adult rats. Neurobiol Dis 2011; 44:239-47. [PMID: 21784155 DOI: 10.1016/j.nbd.2011.07.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 06/16/2011] [Accepted: 07/08/2011] [Indexed: 12/17/2022] Open
Abstract
The glycoprotein reelin is important for embryonic neuronal migration. During adulthood reelin possibly acts as a modulator of synaptic plasticity. Several studies link reduced levels of reelin messenger RNA and protein to the pathophysiology of certain neuropsychiatric disorders. However, little is known about reelin's role for behavioral and cognitive functions in vivo. Therefore, the effect of a reelin knockdown in the medial prefrontal cortex (mPFC) of Wistar rats was examined in behavioral tasks related to neuropsychiatric disorders, such as schizophrenia. Rats treated with reelin antisense phosphothioate oligonucleotides in the mPFC during puberty or adulthood were tested for prepulse inhibition (PPI) of the acoustic startle reflex, spatial working memory, object recognition, and locomotor activity. Reelin quantification in the mPFC was assessed by Western blotting. Local reelin knockdown during puberty or adulthood induced (1) a PPI deficit as well as (2) an impairment of spatial working memory and object recognition following pubertal injections. Western blot analyses showed a distinct and highly selective reelin knockdown in the rats' mPFC. These results indicate that mPFC reelin signaling plays an important role in behavioral tasks with relevance to e.g. schizophrenia. Understanding reelin's function as a neurotrophic modulator of the extracellular matrix may help to achieve new insights into the etiology of certain neuropsychiatric diseases and foster prospective treatment strategies.
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Affiliation(s)
- Jan Brosda
- University of Bremen, Brain Research Institute, Department of Neuropharmacology, Germany.
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20
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Enomoto T, Tse MT, Floresco SB. Reducing prefrontal gamma-aminobutyric acid activity induces cognitive, behavioral, and dopaminergic abnormalities that resemble schizophrenia. Biol Psychiatry 2011; 69:432-41. [PMID: 21146155 DOI: 10.1016/j.biopsych.2010.09.038] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 09/23/2010] [Accepted: 09/24/2010] [Indexed: 12/15/2022]
Abstract
BACKGROUND Perturbations in gamma-aminobutyric acid (GABA)-related markers have been reported in the prefrontal cortex of schizophrenic patients. However, a preclinical assessment of how suppression of prefrontal cortex GABA activity may reflect behavioral and cognitive pathologies observed in schizophrenia is forthcoming. METHODS We assessed the effects of pharmacologic blockade of prefrontal cortex GABA(A) receptors in rats on executive functions and other behaviors related to schizophrenia, as well as neural activity of midbrain dopamine neurons. RESULTS Blockade of prefrontal cortex GABA(A) receptors with bicuculline (12.5-50 ng) did not affect working memory accuracy but did increase response latencies, resembling speed of processing deficits observed in schizophrenia. Prefrontal cortex GABA(A) blockade did not impede simple discrimination or reversal learning but did impair set-shifting in a manner dependent on when these treatments were given. Reducing GABA activity before the set-shift impaired the ability to acquire a novel strategy, whereas treatment before the initial discrimination increased perseveration during the shift. Latent inhibition was unaffected by bicuculline infusions before the preexposure/conditioning phases, suggesting that reduced prefrontal cortex GABA activity does not impair "learned irrelevance." GABA(A) blockade increased locomotor activity and showed synergic effects with a subthreshold dose of amphetamine. Furthermore, reducing medial prefrontal cortex GABA activity selectively increased phasic burst firing of ventral tegmental area dopamine neurons, without altering the their overall population activity. CONCLUSIONS These results suggest that prefrontal cortex GABA hypofunction may be a key contributing factor to deficits in speed of processing, cognitive flexibility, and enhanced phasic dopamine activity observed in schizophrenia.
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Affiliation(s)
- Takeshi Enomoto
- Department of Psychology and Brain Research Centre, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada
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21
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Nelson AJD, Thur KE, Horsley RR, Spicer C, Marsden CA, Cassaday HJ. Reduced dopamine function within the medial shell of the nucleus accumbens enhances latent inhibition. Pharmacol Biochem Behav 2010; 98:1-7. [PMID: 21146557 PMCID: PMC3038261 DOI: 10.1016/j.pbb.2010.11.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 11/22/2010] [Accepted: 11/29/2010] [Indexed: 11/27/2022]
Abstract
Latent inhibition (LI) manifests as poorer conditioning to a CS that has previously been presented without consequence. There is some evidence that LI can be potentiated by reduced mesoaccumbal dopamine (DA) function but the locus within the nucleus accumbens of this effect is as yet not firmly established. Experiment 1 tested whether 6-hydroxydopamine (6-OHDA)-induced lesions of DA terminals within the core and medial shell subregions of the nucleus accumbens (NAc) would enhance LI under conditions that normally disrupt LI in controls (weak pre-exposure). LI was measured in a thirst motivated conditioned emotional response procedure with 10 pre-exposures (to a noise CS) and 2 conditioning trials. The vehicle-injected and core-lesioned animals did not show LI and conditioned to the pre-exposed CS at comparable levels to the non-pre-exposed controls. 6-OHDA lesions to the medial shell, however, produced potentiation of LI, demonstrated across two extinction tests. In a subsequent experiment, haloperidol microinjected into the medial shell prior to conditioning similarly enhanced LI. These results underscore the dissociable roles of core and shell subregions of the NAc in mediating the expression of LI and indicate that reduced DA function within the medial shell leads to enhanced LI.
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Affiliation(s)
- A J D Nelson
- Institute of Neuroscience, School of Psychology, University of Nottingham, United Kingdom
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Ventral striatal noradrenergic mechanisms contribute to sensorimotor gating deficits induced by amphetamine. Neuropsychopharmacology 2010; 35:2346-56. [PMID: 20686455 PMCID: PMC2955791 DOI: 10.1038/npp.2010.106] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The psychotomimetic drug D-amphetamine (AMPH), disrupts prepulse inhibition (PPI) of the startle response, an operational measure of sensorimotor gating that is deficient in schizophrenia patients. Historically, this effect has been attributed to dopaminergic substrates; however, AMPH also increases norepinephrine (NE) levels, and enhancement of central NE transmission has been shown recently to disrupt PPI. This study examined the extent to which NE might participate in AMPH-induced disruptions of PPI and increases in locomotor activity, another classic behavioral effect of AMPH, by determining whether antagonism of postsynaptic NE receptors blocked these effects. Separate groups of male Sprague-Dawley rats received either the α1 receptor antagonist, prazosin (0, 0.3, 1 mg/kg), or the β receptor antagonist timolol (0, 3, 10 mg/kg) before administration of AMPH (0 or 1 mg/kg) before testing for PPI or locomotor activity. As an initial exploration of the anatomical substrates underlying possible α1 receptor-mediated effects on AMPH-induced PPI deficits, the α1 receptor antagonist terazosin (0 or 40 μg/0.5 μl) was microinfused into the nucleus accumbens shell (NAccSh) in conjunction with systemic AMPH administration before startle testing in a separate experiment. Prazosin, but not timolol, blocked AMPH-induced hyperactivity; both drugs reversed AMPH-induced PPI deficits without altering baseline startle responses. Interestingly, AMPH-induced PPI deficits also were partially blocked by terazosin in NAccSh. Thus, behavioral sequelae of AMPH (PPI disruption and hyperactivity) may be mediated in part by NE receptors, with α1 receptors in NAccSh possibly having an important role in the sensorimotor gating deficits induced by this psychotomimetic drug.
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Catecholaminergic depletion within the prelimbic medial prefrontal cortex enhances latent inhibition. Neuroscience 2010; 170:99-106. [PMID: 20619321 PMCID: PMC2930211 DOI: 10.1016/j.neuroscience.2010.06.066] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 06/21/2010] [Accepted: 06/25/2010] [Indexed: 11/24/2022]
Abstract
Latent inhibition (LI) refers to the reduction in conditioning to a stimulus that has received repeated non-reinforced pre-exposure. Investigations into the neural substrates of LI have focused on the nucleus accumbens (NAc) and its inputs from the hippocampal formation and adjacent cortical areas. Previous work has suggested that lesions to the medial prefrontal cortex (mPFC), another major source of input to the NAc, do not disrupt LI. However, a failure to observe disrupted LI does not preclude the possibility that a particular brain region is involved in the expression of LI. Moreover, the mPFC is a heterogeneous structure and there has been no investigation of a possible role of different regions within the mPFC in regulating LI under conditions that prevent LI in controls. Here, we tested whether 6-hydroxydopamine (6-OHDA)-induced lesions of dopamine (DA) terminals within the prelimbic (PL) and infralimbic (IL) mPFC would lead to the emergence of LI under conditions that do produce LI in controls (weak pre-exposure). LI was measured in a thirst motivated conditioned emotional response procedure with 10 pre-exposures to a noise conditioned stimulus (CS) and two conditioning trials. Sham-operated and IL-lesioned animals did not show LI and conditioned to the pre-exposed CS at comparable levels to the non-pre-exposed controls. 6-OHDA lesions to the PL, however, produced potentiation of LI. These results provide the first demonstration that the PL mPFC is a component of the neural circuitry underpinning LI.
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Loskutova LV, Kostyunina NV, Dubrovina NI. Involvement of different types of dopamine receptors in the formation of latent inhibition of a conditioned passive avoidance reaction in rats. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 2010; 40:483-7. [PMID: 20490693 DOI: 10.1007/s11055-010-9285-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2008] [Accepted: 10/20/2008] [Indexed: 01/09/2023]
Abstract
The effects of systemic injections of dopaminergic agents on normal and weak latent inhibition of a conditioned passive avoidance reaction were studied in rats. Formation of normal latent inhibition was induced using 20 pre-exposures to a contextual conditioned stimulus prior to training. Weak latent inhibition was modeled using 10 pre-exposures. The effects of the D(2)/D(3) receptor agonist quinpirole (1 mg/kg) and the D(1) receptor agonist SKF 38393 (1 mg/kg) separately and in combination with haloperidol (0.5 mg/kg) were tested. Quinpirole induced the expression of normal latent inhibition but had no effect on weak latent inhibition. Activation of D(1) receptors with SKF 38393 had no effect on the formation of latent inhibition regardless of the number of pre-exposures. Haloperidol significantly strengthened weak latent inhibition but impaired normal latent inhibition. Administration of haloperidol in combination with SKF 38393 prevented this impairment. These results suggest that while D(1) receptors have no influence as an independent substrate on the formation of latent inhibition, activation of these receptors is required for the complete manifestation of D(2)-mediated modulation of this process.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Avoidance Learning/drug effects
- Avoidance Learning/physiology
- Conditioning, Operant/drug effects
- Conditioning, Operant/physiology
- Dopamine D2 Receptor Antagonists
- Haloperidol/pharmacology
- Male
- Quinpirole/pharmacology
- Rats
- Rats, Wistar
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/physiology
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Affiliation(s)
- L V Loskutova
- State Research Institute of Physiology, Siberian Branch, Russian Academy of Medical Sciences, Novosibirsk, Russia.
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25
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George DN, Duffaud AM, Pothuizen HHJ, Haddon JE, Killcross S. Lesions to the ventral, but not the dorsal, medial prefrontal cortex enhance latent inhibition. Eur J Neurosci 2010; 31:1474-82. [PMID: 20384772 DOI: 10.1111/j.1460-9568.2010.07178.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The acquisition of a conditioned response to a stimulus when it is paired with a reinforcer is retarded if the stimulus has previously been repeatedly pre-exposed in the absence of the reinforcer. This effect, called latent inhibition, has previously been found to be insensitive to lesions of the medial prefrontal cortex (mPFC) in rats. Using an on-baseline conditioned emotional response procedure, which is especially sensitive to small variations in the absolute magnitude of latent inhibition, we found increased latent inhibition following excitotoxic lesions of the mPFC (Experiment 1) or the ventral mPFC alone (Experiment 2) as compared with sham-operated control rats. Lesions restricted to the dorsal mPFC, however, were without effect (Experiment 2). These results are consistent with those of experiments employing another type of interference procedure, extinction. Together, these findings suggest that when different contingencies between a stimulus and a reinforcer are established in separate learning phases, lesions to the ventral mPFC result in increased interference between first-learned and second-learned contingencies. As a consequence, retrieval of the second-learned contingency is impaired, and performance is dominated by the first-learned contingency. These findings are discussed in light of the use of latent inhibition to model cognitive deficits in schizophrenia.
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Schellekens AFA, Grootens KP, Neef C, Movig KLL, Buitelaar JK, Ellenbroek B, Verkes RJ. Effect of apomorphine on cognitive performance and sensorimotor gating in humans. Psychopharmacology (Berl) 2010; 207:559-69. [PMID: 19834690 PMCID: PMC2784073 DOI: 10.1007/s00213-009-1686-1] [Citation(s) in RCA: 17] [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: 02/19/2009] [Accepted: 09/23/2009] [Indexed: 01/04/2023]
Abstract
INTRODUCTION Dysfunction of brain dopamine systems is involved in various neuropsychiatric disorders. Challenge studies with dopamine receptor agonists have been performed to assess dopamine receptor functioning, classically using the release of growth hormone (GH) from the hindbrain as primary outcome measure. The objective of the current study was to assess dopamine receptor functioning at the forebrain level. METHODS Fifteen healthy male volunteers received apomorphine sublingually (2 mg), subcutaneously (0.005 mg/kg), and placebo in a balanced, double-blind, cross-over design. Outcome measures were plasma GH levels, performance on an AX continuous performance test, and prepulse inhibition of the acoustic startle. The relation between central outcome measures and apomorphine levels observed in plasma and calculated in the brain was modeled using a two-compartmental pharmacokinetic-pharmacodynamic analysis. RESULTS After administration of apomorphine, plasma GH increased and performance on the AX continuous performance test deteriorated, particularly in participants with low baseline performance. Apomorphine disrupted prepulse inhibition (PPI) on high-intensity (85 dB) prepulse trials and improved PPI on low intensity (75 dB) prepulse trials, particularly in participants with low baseline PPI. High cognitive performance at baseline was associated with reduced baseline sensorimotor gating. Neurophysiological measures correlated best with calculated brain apomorphine levels after subcutaneous administration. CONCLUSION The apomorphine challenge test appears a useful tool to assess dopamine receptor functioning at the forebrain level. Modulation of the effect of apomorphine by baseline performance levels may be explained by an inverted U-shape relation between prefrontal dopamine functioning and cognitive performance, and mesolimbic dopamine functioning and sensorimotor gating. Future apomorphine challenge tests preferentially use multiple outcome measures, after subcutaneous administration of apomorphine.
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Affiliation(s)
- Arnt F. A. Schellekens
- Department of Psychiatry, Radboud Medical Centre Nijmegen, Reinier Postlaan 10, 966 P.O. Box 9101, 6500 HB Nijmegen, The Netherlands ,Department of Psychiatry, University Medical Centre, Nijmegen, The Netherlands ,Donders Centre for Brain and Cognition, Nijmegen, The Netherlands
| | - K. P. Grootens
- Department of Psychiatry, Radboud Medical Centre Nijmegen, Reinier Postlaan 10, 966 P.O. Box 9101, 6500 HB Nijmegen, The Netherlands ,Department of Psychiatry, University Medical Centre, Nijmegen, The Netherlands ,Donders Centre for Brain and Cognition, Nijmegen, The Netherlands
| | - C. Neef
- Department of Pharmacy and Toxicology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Kris L. L. Movig
- Department of Clinical Pharmacy, Medisch Spectrum Twente, Enschede, The Netherlands
| | - J. K. Buitelaar
- Department of Psychiatry, Radboud Medical Centre Nijmegen, Reinier Postlaan 10, 966 P.O. Box 9101, 6500 HB Nijmegen, The Netherlands ,Department of Psychiatry, University Medical Centre, Nijmegen, The Netherlands ,Donders Centre for Brain and Cognition, Nijmegen, The Netherlands
| | | | - R. J. Verkes
- Department of Psychiatry, Radboud Medical Centre Nijmegen, Reinier Postlaan 10, 966 P.O. Box 9101, 6500 HB Nijmegen, The Netherlands ,Department of Psychiatry, University Medical Centre, Nijmegen, The Netherlands ,Donders Centre for Brain and Cognition, Nijmegen, The Netherlands
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Prenatal exposure to infection: a primary mechanism for abnormal dopaminergic development in schizophrenia. Psychopharmacology (Berl) 2009; 206:587-602. [PMID: 19277608 DOI: 10.1007/s00213-009-1504-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 02/23/2009] [Indexed: 10/21/2022]
Abstract
RATIONALE Prenatal exposure to infection is a notable environmental risk factor in the development of schizophrenia. One prevalent hypothesis suggests that infection-induced disruption of early prenatal brain development predisposes the organism to long-lasting structural and functional brain abnormalities. Many of the prenatal infection-induced functional brain abnormalities appear to be closely associated with imbalances in the mesocorticolimbic dopamine system in adult life, suggesting that disruption of functional and structural dopaminergic development may be at the core of the developmental neuropathology associated with psychosis-related abnormalities induced by prenatal exposure to infection. OBJECTIVES In this review, we integrate recent findings derived from experimental models in animals with parallel research in humans which supports this hypothesis. We thereby highlight the developmental perspective of abnormal DA functions following in-utero exposure to infection in relation to the developmental and maturational mechanisms potentially involved in schizophrenia. RESULTS Experimental investigations show that early prenatal immune challenge can lead to the emergence of early structural and functional alterations in the mesocorticolimbic DA system, long before the onset of the full spectrum of psychosis-associated behavioral and cognitive abnormalities in adulthood. CONCLUSIONS Dopaminergic mal-development in general, and following prenatal immune activation in particular, may represent a primary etiopathological mechanism in the development of schizophrenia and related disorders. This hypothesis differs from the view that dopaminergic abnormalities in schizophrenia may be secondary to abnormalities in other brain structures and/or neurotransmitter systems. The existence of primary dopaminergic mechanisms may have important implications for the identification and early treatment of individuals prodromally symptomatic for schizophrenia.
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Quednow BB, Schmechtig A, Ettinger U, Petrovsky N, Collier DA, Vollenweider FX, Wagner M, Kumari V. Sensorimotor gating depends on polymorphisms of the serotonin-2A receptor and catechol-O-methyltransferase, but not on neuregulin-1 Arg38Gln genotype: a replication study. Biol Psychiatry 2009; 66:614-20. [PMID: 19545856 PMCID: PMC3184478 DOI: 10.1016/j.biopsych.2009.05.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 05/12/2009] [Accepted: 05/12/2009] [Indexed: 01/04/2023]
Abstract
BACKGROUND Prepulse inhibition (PPI) of the acoustic startle response (ASR) is an operational measure of sensorimotor gating and a promising endophenotype of schizophrenia. We have recently shown that the linked serotonin-2A receptor (5-HT(2A)R) A-1438 G and T102C polymorphisms modulate PPI in schizophrenia patients. Moreover, it was shown that genetic variation in the catechol-O-methyltransferase (COMT) and the neuregulin-1 (NRG-1) proteins influences PPI in schizophrenia patients and healthy volunteers. Therefore, we aimed to replicate these results and investigated the impact of the related polymorphisms on PPI in healthy human volunteers. METHODS We analyzed the 5-HT(2A)R A-1438 G/T102C (rs6311/rs6313), the COMT Val158Met (rs4680), and the NRG-1 Arg38Gln (rs3924999) polymorphisms, assessing startle reactivity, habituation, and PPI of ASR in 107 healthy Caucasian volunteers. RESULTS Subjects homozygous for the 5-HT(2A)R T102C-T/A-1438 G-A allele showed increased PPI levels. In particular, male subjects with the COMT Met158Met-genotype also showed elevated PPI. The NRG-1 Arg38Gln genotype did not have a significant impact on PPI. Startle reactivity was not affected by any of the investigated polymorphisms. CONCLUSIONS We confirmed in an independent sample of healthy volunteers that PPI is influenced by genetic variation in the 5-HT(2A)R gene. The influence of the COMT Val158Met genotype on PPI appears to be sex-specific. These results underscore the significance of the serotonin and dopamine systems in the modulation of sensorimotor gating.
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1-Methyl-1,2,3,4-tetrahydroisoquinoline Antagonizes a Rise in Brain Dopamine Metabolism, Glutamate Release in Frontal Cortex and Locomotor Hyperactivity Produced by MK-801 but not the Disruptions of Prepulse Inhibition, and Impairment of Working Memory in Rat. Neurotox Res 2009; 16:390-407. [DOI: 10.1007/s12640-009-9097-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 02/10/2009] [Accepted: 02/10/2009] [Indexed: 10/20/2022]
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Affiliation(s)
- Peter Dayan
- Gatsby Computational Neuroscience Unit, University College London, London, WC1N 3AR, UK;
| | - Quentin J.M. Huys
- Gatsby Computational Neuroscience Unit, University College London, London, WC1N 3AR, UK;
- Center for Theoretical Neuroscience, Columbia University, New York, NY 10025;
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Prenatal immune activation leads to multiple changes in basal neurotransmitter levels in the adult brain: implications for brain disorders of neurodevelopmental origin such as schizophrenia. Int J Neuropsychopharmacol 2009; 12:513-24. [PMID: 18752727 DOI: 10.1017/s1461145708009206] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Maternal infection during pregnancy enhances the offspring's risk for severe neuropsychiatric disorders in later life, including schizophrenia. Recent attempts to model this association in animals provided further experimental evidence for a causal relationship between in-utero immune challenge and the postnatal emergence of a wide spectrum of behavioural, pharmacological and neuroanatomical dysfunctions implicated in schizophrenia. However, it still remains unknown whether the prenatal infection-induced changes in brain and behavioural functions may be associated with multiple changes at the neurochemical level. Here, we tested this hypothesis in a recently established mouse model of viral-like infection. Pregnant dams on gestation day 9 were exposed to viral mimetic polyriboinosinic-polyribocytidilic acid (PolyI:C, 5 mg/kg i.v.) or vehicle treatment, and basal neurotransmitter levels were then compared in the adult brains of animals born to PolyI:C- or vehicle-treated mothers by high-performance liquid chromatography on post-mortem tissue. We found that prenatal immune activation significantly increased the levels of dopamine and its major metabolites in the lateral globus pallidus and prefrontal cortex, whilst at the same time it decreased serotonin and its metabolite in the hippocampus, nucleus accumbens and lateral globus pallidus. In addition, a specific reduction of the inhibitory amino acid taurine in the hippocampus was noted in prenatally PolyI:C-exposed offspring relative to controls, whereas central glutamate and gamma-aminobutyric acid (GABA) content was largely unaffected by prenatal immune activation. Our results thus confirm that maternal immunological stimulation during early/middle pregnancy is sufficient to induce long-term changes in multiple neurotransmitter levels in the brains of adult offspring. This further supports the possibility that infection-mediated interference with early fetal brain development may predispose the developing organism to the emergence of neurochemical imbalances in adulthood, which may be critically involved in the precipitation of adult behavioural and pharmacological abnormalities after prenatal immune challenge.
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Effects of microinjections of apomorphine and haloperidol into the inferior colliculus on the latent inhibition of the conditioned emotional response. Exp Neurol 2009; 216:16-21. [DOI: 10.1016/j.expneurol.2008.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 10/28/2008] [Accepted: 10/30/2008] [Indexed: 11/20/2022]
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Roussos P, Giakoumaki SG, Bitsios P. The dopamine D(3) receptor Ser9Gly polymorphism modulates prepulse inhibition of the acoustic startle reflex. Biol Psychiatry 2008; 64:235-40. [PMID: 18325483 DOI: 10.1016/j.biopsych.2008.01.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 01/02/2008] [Accepted: 01/27/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND The dopamine D(3) receptor (DRD(3)) is suspected to modulate prepulse inhibition (PPI) in animals and humans, but definite conclusions cannot be drawn due to lack of selective DRD(3) ligands. The Ser9Gly polymorphism is a common variant of the DRD(3) gene and determines the gain of function of the D(3) receptor. This is the first study to examine the influence of the DRD(3) Ser9Gly polymorphism on human PPI. METHODS Prepulse inhibition was measured in 101 healthy male subjects presented with 75-dB and 85-dB prepulses at 30-, 60-, and 120-msec prepulse-pulse intervals. Subjects were grouped according to their DRD(3) status into a Gly/Gly, a Ser/Gly, and a Ser/Ser group. RESULTS Analyses of variance showed that at all prepulse and interval conditions, Gly/Gly individuals had the lowest PPI and the greatest onset latency facilitation and Ser/Ser individuals had the highest PPI and the lowest onset latency facilitation, while Ser/Gly individuals were intermediate. CONCLUSIONS These results suggest that PPI is modulated by the D(3) receptor and its levels depend on the Ser9Gly polymorphism.
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Affiliation(s)
- Panos Roussos
- Department of Psychiatry and Behavioral Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece
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Wójcikowski J, Gołembiowska K, Daniel WA. Regulation of liver cytochrome P450 by activation of brain dopaminergic system: Physiological and pharmacological implications. Biochem Pharmacol 2008; 76:258-67. [DOI: 10.1016/j.bcp.2008.04.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 04/25/2008] [Accepted: 04/25/2008] [Indexed: 11/25/2022]
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Alcaro A, Huber R, Panksepp J. Behavioral functions of the mesolimbic dopaminergic system: an affective neuroethological perspective. BRAIN RESEARCH REVIEWS 2007; 56:283-321. [PMID: 17905440 PMCID: PMC2238694 DOI: 10.1016/j.brainresrev.2007.07.014] [Citation(s) in RCA: 295] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 07/03/2007] [Accepted: 07/03/2007] [Indexed: 12/11/2022]
Abstract
The mesolimbic dopaminergic (ML-DA) system has been recognized for its central role in motivated behaviors, various types of reward, and, more recently, in cognitive processes. Functional theories have emphasized DA's involvement in the orchestration of goal-directed behaviors and in the promotion and reinforcement of learning. The affective neuroethological perspective presented here views the ML-DA system in terms of its ability to activate an instinctual emotional appetitive state (SEEKING) evolved to induce organisms to search for all varieties of life-supporting stimuli and to avoid harms. A description of the anatomical framework in which the ML system is embedded is followed by the argument that the SEEKING disposition emerges through functional integration of ventral basal ganglia (BG) into thalamocortical activities. Filtering cortical and limbic input that spreads into BG, DA transmission promotes the "release" of neural activity patterns that induce active SEEKING behaviors when expressed at the motor level. Reverberation of these patterns constitutes a neurodynamic process for the inclusion of cognitive and perceptual representations within the extended networks of the SEEKING urge. In this way, the SEEKING disposition influences attention, incentive salience, associative learning, and anticipatory predictions. In our view, the rewarding properties of drugs of abuse are, in part, caused by the activation of the SEEKING disposition, ranging from appetitive drive to persistent craving depending on the intensity of the affect. The implications of such a view for understanding addiction are considered, with particular emphasis on factors predisposing individuals to develop compulsive drug seeking behaviors.
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Affiliation(s)
- Antonio Alcaro
- Department of Biological Sciences and J.P. Scott Center for Neuroscience, Mind & Behavior, Bowling Green State University, Life Science Building, Bowling Green, OH, 43403, USA
- Santa Lucia Foundation, European Centre for Brain Research (CERC), Via del Fosso di Fiorano 65, 00143 Rome, Italy
| | - Robert Huber
- Department of Biological Sciences and J.P. Scott Center for Neuroscience, Mind & Behavior, Bowling Green State University, Life Science Building, Bowling Green, OH, 43403, USA
| | - Jaak Panksepp
- Department of Biological Sciences and J.P. Scott Center for Neuroscience, Mind & Behavior, Bowling Green State University, Life Science Building, Bowling Green, OH, 43403, USA
- Department of VCAPP, Center for the Study of Animal Well-Being, College of Veterinary Medicine, Washington State University, Pullman, WA 99163, USA
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Featherstone RE, Kapur S, Fletcher PJ. The amphetamine-induced sensitized state as a model of schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:1556-71. [PMID: 17884274 DOI: 10.1016/j.pnpbp.2007.08.025] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Schizophrenia is a serious psychiatric disorder which impacts a broad range of cognitive, behavioural and emotional domains. In animals, exposure to an intermittent, escalating dose regimen of amphetamine induces a sensitized state that appears to share a number of behavioural and neurochemical similarities with schizophrenia. In humans repeated exposure to amphetamine, or other psychomotor stimulants, can induce sensitization as well as psychosis. The following paper evaluates the evidence for the amphetamine-induced sensitized state as an animal model of schizophrenia, focussing separately on the positive, cognitive and negative symptoms associated with this disease. Current evidence supports the use of amphetamine sensitization as a model of the positive symptoms observed in schizophrenia. Additionally, there is increasing evidence for long-lasting cognitive deficits in sensitized animals, especially in the area of attention and/or cognitive flexibility. Other areas of cognition, such as long-term memory, appear to be unaltered in sensitized animals. Finally, little evidence currently exists to either support or refute the use of amphetamine sensitization as a model of negative symptoms. It is concluded that amphetamine sensitization likely impacts behaviour by altering the functioning of mesolimbic dopamine systems and prefrontal cortical function and can serve as a model of certain domains of schizophrenia.
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Affiliation(s)
- R E Featherstone
- Section of Biopsychology, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, Canada M5T 1R8.
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Stevens A, Peschk I, Schwarz J. Implicit learning, executive function and hedonic activity in chronic polydrug abusers, currently abstinent polydrug abusers and controls. Addiction 2007; 102:937-46. [PMID: 17523989 DOI: 10.1111/j.1360-0443.2007.01823.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS The study seeks to evaluate impairments of implicit learning and executive function in chronic polydrug abusers. It was hypothesized that implicit learning and executive function correlate with anhedonia. DESIGN A cross-sectional group comparison. SETTINGS Department of Psychiatry, University of Tübingen, Germany. Participants A total of 25 male polydrug abusers with opiate dependence, n = 26 polydrug abusers abstinent for more than 3 months and n = 26 non-drug-using healthy males. SETTING Abstinent polydrug abusers were recruited from a community treatment centre, current polydrug abusers from local drug counselling services and controls through advertisements. MEASUREMENTS A psychological battery assessing implicit learning (serial reaction-time task), various executive functions (latent inhibition, delayed matching-to-sample, Trail Making Test, acquisition and modification of conditioned responses, figural reasoning) and verbal logic memory was administered. Hedonic thoughts and activities as well as depressive symptoms were assessed through questionnaires. FINDINGS In chronic polydrug abusers, there were moderate impairments of implicit learning, of acquisition, reversal and extinction of conditioned responses, of latent inhibition as well as anhedonia, while working memory was spared. In the abstinent group, cognitive performance was normal except for latent inhibition and more anhedonia and depression than in controls. CONCLUSIONS The findings suggest that current polydrug abusers suffer from impairment of many cognitive functions and from anhedonia. During abstinence, there is near normal cognitive function but still anhedonia. Anhedonia was correlated with implicit learning but not with executive function.
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Affiliation(s)
- Andreas Stevens
- Klinik für Psychiatrie und Psychotherapie, Universität Tübingen, Tübingen, Germany
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Turvin JC, Messer WS, Kritzer MF. On again, off again effects of gonadectomy on the acoustic startle reflex in adult male rats. Physiol Behav 2006; 90:473-82. [PMID: 17169383 PMCID: PMC2517218 DOI: 10.1016/j.physbeh.2006.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 09/02/2006] [Accepted: 10/24/2006] [Indexed: 10/23/2022]
Abstract
Numerous studies have shown sex and/or estrous cycle differences in the acoustic startle reflex (ASR) and its prepulse inhibition (PPI) in humans and animals. However, few have examined the effects of hormone manipulations on these behaviors. This study paired gonadectomy (GDX) in adult male rats with testing for ASR and PPI at 2, 4, 9, 16, 23, 30 and 37 days after surgery. Initial studies of control, GDX and GDX rats given testosterone propionate revealed no group differences in PPI, but did reveal phasic facilitation of the ASR in GDX rats that was greatest on the first and final testing sessions and that was attenuated by testosterone. A second study addressing roles for estrogen and androgen signaling tested new control and GDX rats along with GDX rats given estradiol or the non-aromatizable androgen, 5-alpha-dihydrotestosterone and revealed no group differences in PPI, and increases in ASR in GDX rats that were largest during the first and final testing sessions and that were attenuated by both hormone replacements. However, while responses in GDX rats given testosterone were similar to those of controls, ASR in estradiol- and to a lesser extent in dihydrotestosterone-treated GDX rats were typically lower than in controls. This may suggest that hormone modulation of the ASR requires synergistic estrogen and androgen actions. In the male brain where this can be achieved by local steroid metabolism, the enzymes responsible, e.g., aromatase, could help identify loci in the startle circuitry that may be especially relevant for the hormone modulation observed.
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Affiliation(s)
- Jack C Turvin
- Graduate Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, NY, USA
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Glenthoj BY, Mackeprang T, Svarer C, Rasmussen H, Pinborg LH, Friberg L, Baaré W, Hemmingsen R, Videbaek C. Frontal dopamine D(2/3) receptor binding in drug-naive first-episode schizophrenic patients correlates with positive psychotic symptoms and gender. Biol Psychiatry 2006; 60:621-9. [PMID: 16580642 DOI: 10.1016/j.biopsych.2006.01.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 12/12/2005] [Accepted: 01/10/2006] [Indexed: 12/21/2022]
Abstract
BACKGROUND The aim of the study was to examine extrastriatal dopamine D(2/3) receptor binding and psychopathology in schizophrenic patients, and to relate binding potential (BP) values to psychopathology. METHODS Twenty-five drug-naive schizophrenic patients and 20 healthy controls were examined with single-photon emission computerized tomography (SPECT) using the D(2/3)-receptor ligand [123I]epidepride. RESULTS In the hitherto largest study on extrastriatal D(2/3) receptors we detected a significant correlation between frontal D(2/3) BP values and positive schizophrenic symptoms in the larger group of male schizophrenic patients, higher frontal BP values in male (n = 17) compared to female (n = 8) patients, and - in accordance with this - significantly fewer positive schizophrenic symptoms in the female patients. No significant differences in BP values were observed between patients and controls; the patients, however, had significantly higher BP in the right compared to the left thalamus, whereas no significant hemispheric imbalances were observed in the healthy subjects. CONCLUSIONS The present data are the first to confirm a significant correlation between frontal D(2/3) receptor BP values and positive symptoms in male schizophrenic patients. They are in agreement with the hypothesis that frontal D(2/3) receptor activity is significant for positive psychotic symptoms. Additionally, the data support a thalamic hemispheric imbalance in schizophrenia.
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Affiliation(s)
- Birte Y Glenthoj
- Center for Neuropsychiatric Schizophrenia Research, University of Copenhagen, Department of Psychiatry E, Bispebjerg Hospital, Copenhagen, Denmark.
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de Jong IEM, van den Buuse M. SCH 23390 in the prefrontal cortex enhances the effect of apomorphine on prepulse inhibition of rats. Neuropharmacology 2006; 51:438-46. [PMID: 16740279 DOI: 10.1016/j.neuropharm.2006.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 03/30/2006] [Accepted: 04/04/2006] [Indexed: 10/24/2022]
Abstract
The aim of this study was to investigate the role of dopaminergic activity in the prefrontal cortex in the regulation of prepulse inhibition (PPI) of acoustic startle. Rats were instrumented with permanent indwelling cannulas into the prefrontal cortex region and tested at least one week after surgery using a randomized sequence, repeated-measures protocol. Doses of apomorphine (0.1 mg/kg subcutaneously, s.c.) and MK-801 (0.03 mg/kg s.c.) were obtained from preliminary dose-response studies. Intracerebral injection of 0.5 microg/side of the dopamine D1 receptor antagonist, SCH 23390, significantly enhanced the disruptive effect of apomorphine on PPI, but had no effect on its own or on startle amplitude or habituation. Furthermore, the effect of SCH 23390 on PPI was not seen with a lower dose (0.2 microg/side) or in combination with the NMDA receptor antagonist, MK-801. These data confirm and extend previous reports on the importance of dopaminergic innervation of the prefrontal cortex in the regulation of PPI. It is suggested that apomorphine treatment directly or indirectly activates dopamine D1 receptors in the prefrontal cortex to inhibit its own action on PPI elsewhere in the brain, presumably in the nucleus accumbens. Antagonism of this inhibitory component by SCH 23390 therefore leads to a larger disruption of PPI.
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Affiliation(s)
- Inge E M de Jong
- Behavioural Neuroscience Laboratory, The Mental Health Research Institute of Victoria, Parkville, Melbourne, Vic. 3052, Australia
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Del Arco A, Mora F, Mohammed AH, Fuxe K. Stimulation of D2 receptors in the prefrontal cortex reduces PCP-induced hyperactivity, acetylcholine release and dopamine metabolism in the nucleus accumbens. J Neural Transm (Vienna) 2006; 114:185-93. [PMID: 16897609 DOI: 10.1007/s00702-006-0533-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Accepted: 06/18/2006] [Indexed: 10/24/2022]
Abstract
The aim of the present study was to investigate the effects of stimulation of D2 receptors in the prefrontal cortex (PFC) on spontaneous motor activity and the hyperactivity induced by the psychomimetic phencyclidine (PCP). In addition, the effects of prefrontal D2 stimulation under PCP treatment on dialysate concentrations of acetylcholine, choline, dopamine, DOPAC and HVA in the nucleus accumbens were also investigated. Sprague-Dawley male rats were implanted with guide cannulae to perform bilateral injections into the medial PFC of the D2 agonist quinpirole (1.5 and 5 microg/side). Horizontal and vertical spontaneous motor activity and the motor activity induced by systemic injections of the PCP (5 mg/kg i.p.) were monitored in the open field. PFC injections of quinpirole (1.5 and 5 microg/side) significantly decreased horizontal and vertical spontaneous motor activity in a dose-related manner. These effects were blocked by the D2 antagonist raclopride (5 microg/side). Microinjections of quinpirole (1.5 and 5 microg/side) into the PFC also significantly attenuated the hyperactivity produced by PCP (5 mg/kg i.p.). PCP also increased dialysate concentrations of acetylcholine, and dopamine metabolites in the nucleus accumbens. These increases were also reduced by injections of quinpirole (5 microg/side) into the PFC. These results suggest that the stimulation of prefrontal D2 receptors plays an inhibitory role in regulating spontaneous and PCP-induced motor activity and also in the neurochemical changes produced by PCP in the nucleus accumbens.
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Affiliation(s)
- A Del Arco
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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Salum C, Guimarães FS, Brandão ML, Del Bel EA. Dopamine and nitric oxide interaction on the modulation of prepulse inhibition of the acoustic startle response in the Wistar rat. Psychopharmacology (Berl) 2006; 185:133-41. [PMID: 16402193 DOI: 10.1007/s00213-005-0277-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Accepted: 11/14/2005] [Indexed: 12/28/2022]
Abstract
RATIONALE The nitric oxide (NO)-arginine pathway is intimately connected to the release of dopamine (DA), a neurotransmitter system that may be dysfunctional in schizophrenia. Both schizophrenic patients and rats treated with DA agonists present deficits in sensorimotor gating measured by prepulse inhibition (PPI). OBJECTIVE Our aim was to investigate the interaction between a NO synthase inhibitor, N(G)-nitro-L-arginine (L-NOARG), and the DA agonists, amphetamine (Amph), apomorphine (Apo), bromocriptine (BRC), quinpirole (QNP) and SKF38393, on the modulation of the PPI. METHODS Male Wistar rats received two injections of either L-NOARG (40 mg/kg, i.p.) or saline, 1 h before the test, and the DA agonists or vehicle. Testing began 5 min after treatment with Amph (2 mg/kg, i.p.), Apo (0.5 mg/kg, s.c.) or QNP (0.3 mg/kg and 1.0 mg/kg, s.c.), 120 min after BRC (1 and 40 mg/kg, i.p.) and 15 min after SKF38393 (10 mg/kg, s.c.). The PPI test consisted of 60 presentations divided into pulse (100 dB), prepulse (65, 70, 75 and/or 80 dB) and prepulse + pulse. RESULTS L-NOARG prevented the PPI disruption caused by Amph (2 mg/kg). Apo, QNP and BRC disrupted PPI, but these effects were not significantly changed by L-NOARG. SKF38393 had no significant effect on PPI whether or not preceded by L-NOARG. CONCLUSIONS Our findings show that L-NOARG interacted with Amph, an indirect DA agonist, but not with the direct DA agonists on PPI, suggesting that NO is involved on the dopaminergic modulation of sensorimotor gating, probably by a presynaptic mechanism.
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Affiliation(s)
- C Salum
- Department of Physiology, FORP, University of São Paulo, Av. Café S/N, 14040-904 Ribeirão Preto, SP, Brazil.
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Pothuizen HHJ, Neumann KR, Feldon J, Yee BK. Selective nucleus accumbens core lesions enhance dizocilpine-induced but not apomorphine-induced disruption of prepulse inhibition in rats. Behav Pharmacol 2006; 17:107-17. [PMID: 16495719 DOI: 10.1097/01.fbp.0000190683.00232.ec] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Prepulse inhibition refers to the reduction in startle reaction to a startle-eliciting 'pulse' when it is shortly preceded by a weak 'prepulse' stimulus. The nucleus accumbens plays a pivotal role in the regulation of prepulse inhibition in rats, but the relative contributions of its subregions remain unclear. Here, we investigated the effects of selective excitotoxic lesion restricted to the nucleus accumbens core on prepulse inhibition and its sensitivity to dopaminergic and glutamatergic manipulations known to disrupt prepulse inhibition. We first assessed the effects of selective core lesions on prepulse inhibition, before going on to evaluate whether the lesions affect the sensitivity to the prepulse inhibition-disruptive effects of systemic treatment of the dopamine agonist, apomorphine (0.025 mg/kg, subcutaneous) and of the non-competitive N-methyl-D-aspartate receptor antagonist, dizocilpine (0.1 mg/kg, subcutaneous). Contrary to our expectations, core lesions failed to disrupt prepulse inhibition. The lesions, however, enhanced the disruptive effect of dizocilpine, but not of apomorphine, on prepulse inhibition. Our results thus suggest that nucleus accumbens core can indeed lead to deregulation of prepulse inhibition, perhaps via a disturbance of normal glutamatergic activity.
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Affiliation(s)
- Helen H J Pothuizen
- Laboratory of Behavioural Neurobiology, Swiss Federal Institute of Technology Zurich, Schwerzenbach, Switzerland
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Grottick AJ, Bagnol D, Phillips S, McDonald J, Behan DP, Chalmers DT, Hakak Y. Neurotransmission- and cellular stress-related gene expression associated with prepulse inhibition in mice. ACTA ACUST UNITED AC 2005; 139:153-62. [PMID: 15961183 DOI: 10.1016/j.molbrainres.2005.05.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 05/06/2005] [Accepted: 05/12/2005] [Indexed: 10/25/2022]
Abstract
Prepulse inhibition (PPI) is a cross-species measure of sensorimotor gating. PPI deficits have been associated with a number of neuropsychiatric disorders, including schizophrenia. Differential PPI has been demonstrated also across various inbred mouse strains; however, the molecular mechanisms underlying these differences in sensorimotor gating remain unclear. Here, we sought to identify gene expression in the medial prefrontal cortex (mPFC) of mice associated with PPI using a laser microdissection and microarray analysis-based approach. C57BL/6 mouse substrains were used for the study as they have dramatically different PPI. Transcriptional analysis of closely related substrains was predicted to reduce the detection of genetic variation incidental to the phenotype. Microarray analysis comparing the mPFC of C57BL/6J to C57BL/6NHsd mice revealed neurotransmission- and cellular stress-related transcriptional responses associated with lower PPI. Down-regulation of metabotropic glutamate receptor 5, phospholipase C, and inositol monophosphatase 1 gene expression suggest altered phosphoinositide signaling, while decreased expression of a gamma-amino-butyric acid (GABA)A receptor subunit implies changes in GABAergic signaling. Genes involved in neuronal excitation and protection were also differentially expressed, including up-regulation of five immediate early genes and anti-apoptotic/survival factors as Bcl2-associated athanogene 3 and brain-derived neurotrophic factor. These data support previous findings of genetic influences on PPI, and provide novel insights into the molecular mechanisms regulating sensorimotor gating.
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Affiliation(s)
- Andrew J Grottick
- Arena Pharmaceuticals, Inc., 6166 Nancy Ridge Drive, San Diego, CA 92121, USA
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Peterschmitt Y, Hoeltzel A, Louilot A. Striatal dopaminergic responses observed in latent inhibition are dependent on the hippocampal ventral subicular region. Eur J Neurosci 2005; 22:2059-68. [PMID: 16262643 DOI: 10.1111/j.1460-9568.2005.04366.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We showed recently that behavioural and striatal dopaminergic (DA) responses obtained in latent inhibition are crucially dependent on the parahippocampal region, the entorhinal cortex. In the present study, we investigated the influence exerted by the hippocampal ventral subicular region (SUB) on the DA responses in the anterior part of the dorsal striatum using in vivo voltammetry in freely moving rats and the same latent inhibition paradigm. To that end, the left SUB was temporarily blocked with tetrodotoxin (TTX) during pre-exposure to a new olfactory stimulus (banana odour). During the second session the animals were aversively conditioned to banana odour. With respect to the results obtained during the test session (third presentation of banana odour), similar changes in behaviour and DA levels were obtained in control and conditioned rats microinjected with the solvent, phosphate-buffered saline (PBS), in the SUB, consistently with a latent inhibition phenomenon. In contrast, after reversible inactivation of the SUB during the pre-exposure session, TTX-pre-exposed conditioned animals displayed aversive behaviour in the test session, and anterior striatal DA variations in these animals differed significantly from those obtained in pre-exposed rats injected locally with PBS. Striatal DA variations obtained in conditioned animals microinjected with TTX were also significantly different from those observed in conditioned non-pre-exposed animals. The present data suggest that, in parallel to the entorhinal cortex, the SUB regulates the latent inhibition-related behavioural and DA responses in the anterior part of the dorsal striatum. These data may provide new insight into the pathophysiology of schizophrenic psychoses.
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Affiliation(s)
- Y Peterschmitt
- INSERM U 666 and Institute of Physiology, Louis Pasteur University, Faculty of Medicine, 11 rue Humann, 67085 Strasbourg CEDEX, France
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Bitsios P, Giakoumaki SG, Frangou S. The effects of dopamine agonists on prepulse inhibition in healthy men depend on baseline PPI values. Psychopharmacology (Berl) 2005; 182:144-52. [PMID: 16010540 DOI: 10.1007/s00213-005-0056-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 04/27/2005] [Indexed: 11/24/2022]
Abstract
RATIONALE AND OBJECTIVES Dopamine (DA) agonists reliably disrupt prepulse inhibition (PPI) of the startle reflex in animals but less so in humans despite cross-species similarities in the neural regulation of PPI. This study examines whether individual variation in baseline PPI may account for the inconsistencies in DA agonist-induced PPI disruption in humans. METHODS Baseline PPI measures were obtained from 32 healthy adult men. Subjects were subsequently tested in three sessions after ingestion of placebo or active drug in a balanced double-blind design. Seventeen subjects were given 0.05 and 0.1 mg of pergolide (a direct DA agonist) and 15 subjects were given 100 and 200 mg of amantadine (an indirect DA agonist). In each treatment group, subjects were assigned to "high" and "low" PPI subgroups based on the median split of their baseline PPI. RESULTS Amantadine and pergolide disrupted PPI in high- but not in low-PPI subjects. In contrast, low-PPI subjects showed a trend towards PPI facilitation especially with pergolide. CONCLUSIONS Our results suggest that baseline PPI is an important determinant of the effect of DA agonists on PPI.
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Affiliation(s)
- Panos Bitsios
- Department of Psychiatry and Behavioural Sciences, Faculty of Medicine, University of Crete, P.O. BOX 2208, Heraklion, 71003, Crete, Greece.
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Meyer U, Feldon J, Schedlowski M, Yee BK. Towards an immuno-precipitated neurodevelopmental animal model of schizophrenia. Neurosci Biobehav Rev 2005; 29:913-47. [PMID: 15964075 DOI: 10.1016/j.neubiorev.2004.10.012] [Citation(s) in RCA: 370] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2004] [Revised: 10/19/2004] [Accepted: 10/19/2004] [Indexed: 01/18/2023]
Abstract
Epidemiological studies have indicated an association between maternal bacterial and viral infections during pregnancy and the higher incidence of schizophrenia in the resultant offspring post-puberty. One hypothesis asserts that the reported epidemiological link is mediated by prenatal activation of the foetal immune system in response to the elevation of maternal cytokine level due to infection. Here, we report that pregnant mouse dams receiving a single exposure to the cytokine-releasing agent, polyriboinosinic-polyribocytidilic acid (PolyI:C; at 2.5, 5.0, or 10.0 mg/kg) on gestation day 9 produced offspring that subsequently exhibited multiple schizophrenia-related behavioural deficits in adulthood, in comparison to offspring from vehicle injected or non-injected control dams. The efficacy of the PolyI:C challenge to induce cytokine responses in naïve non-pregnant adult female mice and in foetal brain tissue when injected to pregnant mice were further ascertained in separate subjects: (i) a dose-dependent elevation of interleukin-10 was detected in the adult female mice at 1 and 6h post-injection, (ii) 12 h following prenatal PolyI:C challenge, the foetal levels of interleukin-1beta were elevated. The spectrum of abnormalities included impairments in exploratory behaviour, prepulse inhibition, latent inhibition, the US-pre-exposure effect, spatial working memory; and enhancement in the locomotor response to systemic amphetamine (2.5 mg/kg, i.p.) as well as in discrimination reversal learning. The neuropsychological parallels between prenatal PolyI:C treatment in mice and psychosis in humans, demonstrated here, leads us to conclude that prenatal PolyI:C treatment represents one of the most powerful environmental-developmental models of schizophrenia to date. The uniqueness of this model lies in its epidemiological and immunological relevance. It is, sui generis, ideally suited for the investigation of the neuropsychoimmunological mechanisms implicated in the developmental aetiology and disease processes of schizophrenia.
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Affiliation(s)
- Urs Meyer
- Laboratory of Behavioural Neurobiology, Swiss Federal Institute of Technology Zurich, Schorenstrasse 16, Schwerzenbach 8603, Switzerland
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Role of prefrontal cortex in stress responsivity. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0921-0709(05)80043-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Leng A, Feldon J, Ferger B. Long-term social isolation and medial prefrontal cortex: dopaminergic and cholinergic neurotransmission. Pharmacol Biochem Behav 2004; 77:371-9. [PMID: 14751467 DOI: 10.1016/j.pbb.2003.11.011] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Rearing rats in social isolation has been suggested as an animal model of schizophrenia, based mainly on the similarity between the attenuation of prepulse inhibition (PPI) in isolated rats and in schizophrenic patients. The medial prefrontal cortex (mPFC) plays a major role in the pathophysiology of schizophrenia. Thus, a postmortem micropunch analysis measuring dopamine (DA), DOPAC (3,4-dihydroxyphenylacetic acid) and homovanillic acid (HVA) in the dorsal and ventral subregion of the mPFC, the caudate putamen (CPu) and nucleus accumbens (NAc) was carried out on socially isolated or group-housed male Sprague-Dawley (SD) rats. Additionally, in vivo microdialysis with D-amphetamine (1 mg/kg ip) stimulation was performed in isolated animals and their controls, examining the ventral mPFC for acetylcholine (ACh), DOPAC and HVA levels. Simultaneously, recording of motor activity was performed. In the neurochemical postmortem tissue analysis we found no difference in any of the brain regions tested between isolated and group-reared animals. Amphetamine increased ACh levels in the mPFC, induced a decrease in DOPAC and HVA levels, and increased motor activity. A close to significant Drug x Housing interaction reflected the fact that the amphetamine-induced decrease of DOPAC was confined to the group-housed animals. In conclusion, social isolation leads only to moderate changes in the dopaminergic system in the mPFC, whereas the cholinergic system remains unaffected.
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Affiliation(s)
- Andreas Leng
- Behavioral Neurobiology Laboratory, Swiss Federal Institute of Technology Zurich, Schorenstrasse 16, CH-8603, Schwerzenbach, Switzerland
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Schiller D, Weiner I. Lesions to the basolateral amygdala and the orbitofrontal cortex but not to the medial prefrontal cortex produce an abnormally persistent latent inhibition in rats. Neuroscience 2004; 128:15-25. [PMID: 15450350 DOI: 10.1016/j.neuroscience.2004.06.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2004] [Indexed: 11/23/2022]
Abstract
Repeated nonreinforced preexposure to a stimulus interferes with the establishment of conditioned responding to this stimulus when it is subsequently paired with reinforcement. This stimulus-preexposure effect is known as latent inhibition (LI). Rather remarkably, LI appears to be resistant to the effects of numerous lesions, including the prefrontal cortex (PFC) and the basolateral amygdala (BLA). However, intact behavioral expression of LI following damage to given brain regions does not preclude the possibility that such regions participate in the regulation of LI expression in the intact brain. The present study showed that lesions of the BLA and the orbitofrontal cortex (OFC) but not of the medial PFC (mPFC) led to an abnormally persistent LI which emerged under conditions that disrupted LI in control rats. LI was measured in a thirst motivated conditioned emotional response procedure by comparing suppression of drinking in response to a tone in rats which received 0 (nonpreexposed) or 40 tone presentations (preexposed) followed by either two or five tone-shock pairings. Control rats showed LI with 40 preexposures and two conditioning trials, but raising the number of conditioning trials to five disrupted LI. OFC- and BLA-lesioned rats showed LI under the former condition but in addition persisted in exhibiting LI under the latter condition. Rats with lesion of the mPFC did not show persistent LI. Thus, although LI does not depend on the integrity of BLA and OFC (because it is present in BLA- and OFC- lesioned rats even under conditions disrupting the phenomenon in normal rats), these regions play an important role in the modulation of its expression, more specifically, in the control of the non-expression of LI when the impact of conditioning increases beyond a certain level.
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Affiliation(s)
- D Schiller
- Department of Psychology, Tel-Aviv University, Ramat Aviv, Tel-Aviv 69978, P.O.B. 39040, Israel
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