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Yegla B, Rani A, Kumar A. Viral vector-mediated upregulation of serine racemase expression in medial prefrontal cortex improves learning and synaptic function in middle age rats. Aging (Albany NY) 2023; 15:2433-2449. [PMID: 37052995 PMCID: PMC10120901 DOI: 10.18632/aging.204652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
An age-associated decrease in N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic function contributes to impaired synaptic plasticity and is associated with cognitive impairments. Levels of serine racemase (SR), an enzyme that synthesizes D-serine, an NMDAR co-agonist, decline with age. Thus, enhancing NMDAR function via increased SR expression in middle age, when subtle declines in cognition emerge, was predicted to enhance performance on a prefrontal cortex-mediated task sensitive to aging. Middle-aged (~12 mo) male Fischer-344 rats were injected bilaterally in the medial prefrontal cortex (mPFC) with viral vector (LV), SR (LV-SR) or control (LV-GFP). Rats were trained on the operant attentional set-shift task (AST) to examine cognitive flexibility and attentional function. LV-SR rats exhibited a faster rate of learning compared to controls during visual discrimination of the AST. Extradimensional set shifting and reversal were not impacted. Immunohistochemical analyses demonstrated that LV-SR significantly increased SR expression in the mPFC. Electrophysiological characterization of synaptic transmission in the mPFC slices obtained from LV-GFP and LV-SR animals indicated a significant increase in isolated NMDAR-mediated synaptic responses in LV-SR slices. Thus, results of the current study demonstrated that prefrontal SR upregulation in middle age rats can improve learning of task contingencies for visual discrimination and increase glutamatergic synaptic transmission, including NMDAR activity.
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Affiliation(s)
- Brittney Yegla
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Asha Rani
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
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Thonnard D, Dreesen E, Callaerts-Vegh Z, D'Hooge R. NMDA receptor dependence of reversal learning and the flexible use of cognitively demanding search strategies in mice. Prog Neuropsychopharmacol Biol Psychiatry 2019; 90:235-244. [PMID: 30529376 DOI: 10.1016/j.pnpbp.2018.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 11/29/2018] [Accepted: 12/05/2018] [Indexed: 10/27/2022]
Abstract
Cognitive flexibility helps organisms to respond adaptively to environmental changes. Deficits in this executive function have been associated with a variety of brain disorders, and it has been shown to rely on various concomitant neurobiological mechanisms. However, the involvement of the glutamatergic system in general, and NMDA receptors in particular, has been debated. Therefore, we injected C57BL/6 mice repeatedly with low-doses of the non-competitive NMDA receptor antagonist MK-801 (dizocilpine, 0.1 mg/kg, i.p.). Reversal learning and the use of specific cognitive strategies were assessed in a non-spatial discrimination touchscreen task and the Morris water maze (MWM) spatial learning task. In addition, mice were subjected to a non-mnemonic test battery. Although initial acquisition learning was not affected by MK-801 administration, it did induce deficits in reversal learning, both in the non-spatial and spatial task. Defects in non-spatial reversal learning appeared to be caused by perseverative errors. Also, MK-801 administration induced perseverative behaviours as well as inefficient spatial strategy use during MWM reversal learning. These effects could not be reduced to changes in exploratory (anxiety-related) behaviours, nor to motor deficits. This was consistent with results in the non-mnemonic test battery, during which MK-801 evoked hyperlocomotion and subtle motor defects, but failed to alter general motor activity and exploratory behaviours. In conclusion, NMDA receptors appear to be involved in the flexible cognitive processes that underlie reversal learning in spatial as well as non-spatial tasks. Our results also indicate that reversal learning as well as the use of cognitively demanding strategies are more sensitive to NMDA receptor blockage than some other functions that have been suggested to be NMDA receptor dependent.
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Affiliation(s)
- David Thonnard
- Laboratory of Biological Psychology, University of Leuven, Belgium
| | - Eline Dreesen
- Laboratory of Biological Psychology, University of Leuven, Belgium
| | | | - Rudi D'Hooge
- Laboratory of Biological Psychology, University of Leuven, Belgium.
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Yates JR, Gunkel BT, Rogers KK, Hughes MN, Prior NA. Effects of N-methyl-D-aspartate receptor ligands on sensitivity to reinforcer magnitude and delayed reinforcement in a delay-discounting procedure. Psychopharmacology (Berl) 2017; 234:461-473. [PMID: 27837332 PMCID: PMC5226882 DOI: 10.1007/s00213-016-4469-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 11/02/2016] [Indexed: 11/26/2022]
Abstract
RATIONALE The N-methyl-D-aspartate (NMDA) receptor has been recently identified as an important mediator of impulsive choice, as assessed in delay discounting. Although discounting is independently influenced by sensitivity to reinforcer magnitude and delayed reinforcement, few studies have examined how NMDA receptor ligands differentially affect these parameters. OBJECTIVES The current study examined the effects of various NMDA receptor ligands on sensitivity to reinforcer magnitude and delayed reinforcement in a delay-discounting procedure. METHODS Following behavioral training, rats received treatments of the following NMDA receptor ligands: the uncompetitive antagonists ketamine (0, 1.0, 5.0, or 10.0 mg/kg; i.p.), MK-801 (0, 0.003, 0.01, or 0.03 mg/kg; s.c.), and memantine (0, 2.5, 5.0, or 10.0 mg/kg; i.p.), the competitive antagonist CGS 19755 (0, 5.0, 10.0, or 20.0 mg/kg; s.c.), the non-competitive NR2B subunit-selective antagonist ifenprodil (0, 1.0, 3.0, or 10.0 mg/kg; i.p), and the partial agonist D-cycloserine (0, 3.25, 15.0, or 30.0 mg/kg; s.c.). RESULTS When an exponential model was used to describe discounting, CGS 19755 (5.0 mg/kg) increased impulsive choice without altering sensitivity to reinforcer magnitude. Conversely, ketamine (10.0 mg/kg), memantine (5.0 mg/kg), and ifenprodil (10.0 mg/kg) decreased sensitivity to reinforcer magnitude without altering impulsive choice. MK-801 and D-cycloserine did not alter delay-discounting performance, although two-way ANOVA analyses indicated D-cycloserine (15.0 mg/kg) decreased impulsive choice. CONCLUSIONS The behavioral changes observed in delay discounting following administration of NMDA receptor antagonists do not always reflect an alteration in impulsive choice. These results emphasize the utility in employing quantitative methods to assess drug effects in delay discounting.
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Affiliation(s)
- Justin R Yates
- Department of Psychological Science, Northern Kentucky University, 1 Nunn Drive, Highland Heights, KY, 41099, USA.
| | - Benjamin T Gunkel
- Department of Psychological Science, Northern Kentucky University, 1 Nunn Drive, Highland Heights, KY, 41099, USA
| | - Katherine K Rogers
- Department of Psychological Science, Northern Kentucky University, 1 Nunn Drive, Highland Heights, KY, 41099, USA
| | - Mallory N Hughes
- Department of Psychological Science, Northern Kentucky University, 1 Nunn Drive, Highland Heights, KY, 41099, USA
| | - Nicholas A Prior
- Department of Psychological Science, Northern Kentucky University, 1 Nunn Drive, Highland Heights, KY, 41099, USA
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Hvoslef-Eide M, Mar AC, Nilsson SRO, Alsiö J, Heath CJ, Saksida LM, Robbins TW, Bussey TJ. The NEWMEDS rodent touchscreen test battery for cognition relevant to schizophrenia. Psychopharmacology (Berl) 2015. [PMID: 26202612 DOI: 10.1007/s00213-015-4007-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
RATIONALE The NEWMEDS initiative (Novel Methods leading to New Medications in Depression and Schizophrenia, http://www.newmeds-europe.com ) is a large industrial-academic collaborative project aimed at developing new methods for drug discovery for schizophrenia. As part of this project, Work package 2 (WP02) has developed and validated a comprehensive battery of novel touchscreen tasks for rats and mice for assessing cognitive domains relevant to schizophrenia. OBJECTIVES This article provides a review of the touchscreen battery of tasks for rats and mice for assessing cognitive domains relevant to schizophrenia and highlights validation data presented in several primary articles in this issue and elsewhere. METHODS The battery consists of the five-choice serial reaction time task and a novel rodent continuous performance task for measuring attention, a three-stimulus visual reversal and the serial visual reversal task for measuring cognitive flexibility, novel non-matching to sample-based tasks for measuring spatial working memory and paired-associates learning for measuring long-term memory. RESULTS The rodent (i.e. both rats and mice) touchscreen operant chamber and battery has high translational value across species due to its emphasis on construct as well as face validity. In addition, it offers cognitive profiling of models of diseases with cognitive symptoms (not limited to schizophrenia) through a battery approach, whereby multiple cognitive constructs can be measured using the same apparatus, enabling comparisons of performance across tasks. CONCLUSION This battery of tests constitutes an extensive tool package for both model characterisation and pre-clinical drug discovery.
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Affiliation(s)
- M Hvoslef-Eide
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK. .,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK.
| | - A C Mar
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK.,Department of Neuroscience and Physiology, New York University Medical Center, New York, NY, 10016, USA
| | - S R O Nilsson
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
| | - J Alsiö
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK.,Department of Neuroscience, Unit of Functional Neurobiology, University of Uppsala, 75124, Uppsala, Sweden
| | - C J Heath
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
| | - L M Saksida
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
| | - T W Robbins
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
| | - T J Bussey
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.,MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
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Talpos JC, Riordan J, Olley J, Waddell J, Steckler T. Opposing effects of glutamatergic and GABAergic pharmacological manipulations on a visual perception task with relevance to schizophrenia. Psychopharmacology (Berl) 2015; 232:3967-76. [PMID: 26014109 DOI: 10.1007/s00213-015-3964-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/07/2015] [Indexed: 12/12/2022]
Abstract
RATIONALE Numerous psychiatric disorders and neurodegenerative diseases have been associated with differences in visual perception, and it has been proposed that the treatment of these differences may represent a novel means to treat disorders like schizophrenia. Unfortunately, few methods exist to study visual perception in pre-clinical species. OBJECTIVE The purpose of the present study was to adapt a task of visual integration by proximity with relevance to schizophrenia to a rodent touchscreen environment to determine the effects of glutamatergic and GABAergic compounds. In this way, we could evaluate the effects of common models of cognitive impairment, as well as the effects of net excitation versus inhibition, on a task of visual integration. METHOD Rats were trained to perform a visual discrimination where the stimuli were composed of rows of dots differing only in there horizontal and vertical proximity. Once stable performance had been achieved, animals were tested under the influence of glutamatergic or GABAergic drugs (ketamine, MK-801, PCP, memantine, chlordiazepoxide, or diazepam) while attempting to perform a visual discrimination with altered stimuli. RESULTS Ketamine appeared to impair perceptual grouping in this paradigm, while the GABA agonist chlordiazepoxide enhanced grouping even in the presence of non-selective effects. CONCLUSIONS In general, these findings support the theory that NMDA antagonists may disrupt visual grouping by proximity and highlight a potential beneficial effect of enhanced GABA activity in perception. However, additional research will be required to confirm the stimulus selectivity of this effect, and the clinical significance of this approach.
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Affiliation(s)
- John C Talpos
- Department of Neuroscience, Janssen Research and Development, 30 Turnhoutseweg, 2340, Beerse, Belgium.
| | - John Riordan
- Department of Neuroscience, Janssen Research and Development, 30 Turnhoutseweg, 2340, Beerse, Belgium
| | - Joseph Olley
- Department of Neuroscience, Janssen Research and Development, 30 Turnhoutseweg, 2340, Beerse, Belgium
| | - Jason Waddell
- Open Analytics, 20 Jupiterstraat, 2600, Antwerp, Belgium
| | - Thomas Steckler
- Department of Neuroscience, Janssen Research and Development, 30 Turnhoutseweg, 2340, Beerse, Belgium
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