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The effects of acute Cannabis smoke or Δ9-THC injections on the trial-unique, nonmatching-to- location and five-choice serial reaction time tasks in male Long-Evans rats. Neurobiol Learn Mem 2022; 192:107624. [DOI: 10.1016/j.nlm.2022.107624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 04/08/2022] [Accepted: 04/24/2022] [Indexed: 11/18/2022]
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2
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Smith SM, Zequeira S, Ravi M, Johnson SA, Hampton AM, Ross AM, Pyon W, Maurer AP, Bizon JL, Burke SN. Age-related impairments on the touchscreen paired associates learning (PAL) task in male rats. Neurobiol Aging 2022; 109:176-191. [PMID: 34749169 PMCID: PMC9351724 DOI: 10.1016/j.neurobiolaging.2021.09.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/25/2021] [Accepted: 09/27/2021] [Indexed: 02/01/2023]
Abstract
Discovery research in rodent models of cognitive aging is instrumental for identifying mechanisms of behavioral decline in old age that can be therapeutically targeted. Clinically relevant behavioral paradigms, however, have not been widely employed in aged rats. The current study aimed to bridge this translational gap by testing cognition in a cross-species touchscreen-based platform known as paired-associates learning (PAL) and then utilizing a trial-by-trial behavioral analysis approach. This study found age-related deficits in PAL task acquisition in male rats. Furthermore, trial-by-trial analyses and testing rats on a novel interference version of PAL suggested that age-related impairments were not due to differences in vulnerability to an irrelevant distractor, motivation, or to forgetting. Rather, impairment appeared to arise from vulnerability to accumulating, proactive interference, with aged animals performing worse than younger rats in later trial blocks within a single testing session. The detailed behavioral analysis employed in this study provides new insights into the etiology of age-associated cognitive deficits.
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Affiliation(s)
- Samantha M Smith
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA; Graduate Program in Biomedical Sciences, Neuroscience Concentration, University of Florida College of Medicine, Gainesville, FL, USA
| | - Sabrina Zequeira
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA; Graduate Program in Biomedical Sciences, Neuroscience Concentration, University of Florida College of Medicine, Gainesville, FL, USA
| | - Meena Ravi
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA
| | - Sarah A Johnson
- Department of Neuroscience and Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, Chicago, IL, USA
| | - Andriena M Hampton
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA
| | - Aleyna M Ross
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA; Graduate Program in Biomedical Sciences, Neuroscience Concentration, University of Florida College of Medicine, Gainesville, FL, USA
| | - Wonn Pyon
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA; Graduate Program in Biomedical Sciences, Neuroscience Concentration, University of Florida College of Medicine, Gainesville, FL, USA
| | - Andrew P Maurer
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jennifer L Bizon
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA
| | - Sara N Burke
- Department of Neuroscience, Center for Cognitive Aging and Memory, University of Florida College of Medicine, Gainesville, FL, USA; Institute on Aging, University of Florida, Gainesville, FL, USA.
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Onofrychuk TJ, Cai S, McElroy DL, Roebuck AJ, Greba Q, Garai S, Thakur GA, Laprairie RB, Howland JG. Effects of the cannabinoid receptor 1 positive allosteric modulator GAT211 and acute MK-801 on visual attention and impulsivity in rats assessed using the five-choice serial reaction time task. Prog Neuropsychopharmacol Biol Psychiatry 2021; 109:110235. [PMID: 33373679 DOI: 10.1016/j.pnpbp.2020.110235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/07/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022]
Abstract
Altered interactions between endocannabinoid and glutamate signaling may be involved in the pathophysiology of schizophrenia and acute psychosis. As cognitive disturbances are involved in schizophrenia, increased understanding of the roles of these neurotransmitter systems in cognition may lead to the development of novel therapeutics for disorder. In the present study, we examined the effects of a recently synthesized cannabinoid receptor 1 (CB1R) positive allosteric modulator GAT211 in a rodent model of acute psychosis induced by systemic treatment with MK-801. To assess cognitive function, we used the Five-Choice Serial Reaction Time (5CSRT) task, conducted in touchscreen-equipped operant conditioning chambers. Our measures of primary interest were accuracy - indicative of visual attentional capacity - and the number of premature responses - indicative of impulsivity. We also measured latencies, omissions, and perseverative responding during all test sessions. Thirteen adult male Long Evans rats were trained on the 5CSRT and were then tested using a repeated measures design with acute MK-801 (0 or 0.15 mg/kg, i.p.) and GAT211 (0, 3, or 10 mg/kg, i.p.) administration. Acute MK-801 severely impaired accuracy, increased omissions, and increased the number of premature responses. MK-801 also significantly increased correct response latencies, without significant effects on incorrect or reward correction latencies. GAT211 had no significant effects when administered alone, or in combination with acute MK-801. These data confirm the dramatic effects of acute MK-801 treatment on behavioral measures of attention and impulsivity. Continued investigation of CB1R positive allosteric modulators as potential treatments for the cognitive symptoms of schizophrenia and related disorders should be pursued in other rodent models.
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Affiliation(s)
- Timothy J Onofrychuk
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Shuang Cai
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Dan L McElroy
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | | | - Quentin Greba
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - John G Howland
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
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Scott GA, Terstege DJ, Roebuck AJ, Gorzo KA, Vu AP, Howland JG, Epp JR. Adult neurogenesis mediates forgetting of multiple types of memory in the rat. Mol Brain 2021; 14:97. [PMID: 34174906 PMCID: PMC8236170 DOI: 10.1186/s13041-021-00808-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/08/2021] [Indexed: 11/30/2022] Open
Abstract
The formation and retention of hippocampus-dependent memories is impacted by neurogenesis, a process that involves the production of new neurons in the dentate gyrus of the hippocampus. Recent studies demonstrate that increasing neurogenesis after memory formation induces forgetting of previously acquired memories. Neurogenesis-induced forgetting was originally demonstrated in mice, but a recent report suggests that the same effect may be absent in rats. Although a general species difference is possible, other potential explanations for these incongruent findings are that memories which are more strongly reinforced become resilient to forgetting or that perhaps only certain types of memories are affected. Here, we investigated whether neurogenesis-induced forgetting occurs in rats using several hippocampus-dependent tasks including contextual fear conditioning (CFC), the Morris Water Task (MWT), and touchscreen paired associates learning (PAL). Neurogenesis was increased following training using voluntary exercise for 4 weeks before recall of the previous memory was assessed. We show that voluntary running causes forgetting of context fear memories in a neurogenesis-dependent manner, and that neurogenesis-induced forgetting is present in rats across behavioral tasks despite differences in complexity or reliance on spatial, context, or object memories. In addition, we asked whether stronger memories are less susceptible to forgetting by varying the strength of training. Even with a very strong training protocol in the CFC task, we still observed enhanced forgetting related to increased neurogenesis. These results suggest that forgetting due to neurogenesis is a conserved mechanism that aids in the clearance of memories.
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Affiliation(s)
- Gavin A Scott
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, HMRB 162, Health Sciences Centre, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Dylan J Terstege
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, HMRB 162, Health Sciences Centre, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Andrew J Roebuck
- Yukon University, 500 University Drive, Whitehorse, YT, Y1A 5K4, Canada
| | - Kelsea A Gorzo
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, HMRB 162, Health Sciences Centre, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Alex P Vu
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, HMRB 162, Health Sciences Centre, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - John G Howland
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, S7N 5E5, Canada
| | - Jonathan R Epp
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, HMRB 162, Health Sciences Centre, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
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5
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Differential effects of d- and l-enantiomers of govadine on distinct forms of cognitive flexibility and a comparison with dopaminergic drugs. Psychopharmacology (Berl) 2021; 238:1069-1085. [PMID: 33432392 DOI: 10.1007/s00213-020-05754-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Abstract
RATIONALE There is an urgent need for novel drugs for treating cognitive deficits that are defining features of schizophrenia. The individual d- and l-enantiomers of the tetrahydroprotoberberine (THPB) d,l-govadine have been proposed for the treatment of cognitive deficiencies and positive symptoms of schizophrenia, respectively. OBJECTIVES We examined the effects of d-, l-, or d,l-govadine on two distinct forms of cognitive flexibility perturbed in schizophrenia and compared them to those induced by a selective D1 receptor agonist and D2 receptor antagonist. METHODS Male rats received d-, l-, or d,l-govadine (0.3, 0.5, and 1.0 mg/kg), D1 agonist SKF81297(0.1, 0.3, and 1.0 mg/kg), or D2 antagonist haloperidol (0.1-0.2 mg/kg). Experiment 1 used a strategy set-shifting task (between-subjects). In experiment 2, well-trained rats were tested on a probabilistic reversal task (within-subjects). RESULTS d-Govadine improved set-shifting across all doses, whereas higher doses of l-govadine impaired set-shifting. SKF81297 reduced perseverative errors at the lowest dose. Low/high doses of haloperidol increased/decreased set-shifting errors, the latter "improvement" attributable to impaired retrieval of a previous acquired rule. Probabilistic reversal performance was less affected by these drugs, but d-govadine reduced errors during the first reversal, whereas l-govadine impaired initial discrimination learning. d,l-Govadine had no reliable cognitive effects but caused psychomotor slowing like l-govadine and haloperidol. CONCLUSIONS These findings further highlight differences between two enantiomers of d,l-govadine that may reflect differential modulation of D1 and D2 receptors. These preclinical findings give further impetus to formal clinical evaluation of d-govadine as a treatment for cognitive deficiencies related to schizophrenia.
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Anderson MD, Paylor JW, Scott GA, Greba Q, Winship IR, Howland JG. ChABC infusions into medial prefrontal cortex, but not posterior parietal cortex, improve the performance of rats tested on a novel, challenging delay in the touchscreen TUNL task. ACTA ACUST UNITED AC 2020; 27:222-235. [PMID: 32414940 PMCID: PMC7233150 DOI: 10.1101/lm.050245.119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 02/27/2020] [Indexed: 01/04/2023]
Abstract
Perineuronal nets (PNNs) are specialized extracellular matrix structures that surround subsets of neurons throughout the central nervous system (CNS). They are made up of chondroitin sulfate proteoglycans (CSPGs), hyaluronan, tenascin-R, and many other link proteins that together make up their rigid and lattice-like structure. Modulation of PNNs can alter synaptic plasticity and thereby affect learning, memory, and cognition. In the present study, we degraded PNNs in the medial prefrontal (mPFC) and posterior parietal (PPC) cortices of Long–Evans rats using the enzyme chondroitinase ABC (ChABC), which cleaves apart CSPGs. We then measured the consequences of PNN degradation on spatial working memory (WM) with a trial-unique, non-matching-to location (TUNL) automated touchscreen task. All rats were trained with a standard 6 sec delay and 20 sec inter-trial interval (ITI) and then tested under four different conditions: a 6 sec delay, a variable 2 or 6 sec delay, a 2 sec delay with a 1 sec ITI (interference condition), and a 20 sec delay. Rats that received mPFC ChABC treatment initially performed TUNL with higher accuracy, more selection trials completed, and fewer correction trials completed compared to controls in the 20 sec delay condition but did not perform differently from controls in any other condition. Rats that received PPC ChABC treatment did not perform significantly differently from controls in any condition. Posthumous immunohistochemistry confirmed an increase in CSPG degradation products (C4S stain) in the mPFC and PPC following ChABC infusions while WFA staining intensity and parvalbumin positive neuron number were decreased following mPFC, but not PPC, ChABC infusions. These findings suggest that PNNs in the mPFC play a subtle role in spatial WM, but PNNs in the PPC do not. Furthermore, it appears that PNNs in the mPFC are involved in adapting to a challenging novel delay, but that they do not play an essential role in spatial WM function.
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Affiliation(s)
- Michael D Anderson
- Department of Anatomy, Physiology and Pharmacology University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - John W Paylor
- Department of Psychiatry, University of Alberta, Edmonton, Alberta T6G 2B7, Canada
| | - Gavin A Scott
- Department of Anatomy, Physiology and Pharmacology University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Quentin Greba
- Department of Anatomy, Physiology and Pharmacology University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Ian R Winship
- Department of Psychiatry, University of Alberta, Edmonton, Alberta T6G 2B7, Canada
| | - John G Howland
- Department of Anatomy, Physiology and Pharmacology University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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7
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Nesbit MO, Phillips AG. Tetrahydroprotoberberines: A Novel Source of Pharmacotherapies for Substance Use Disorders? Trends Pharmacol Sci 2020; 41:147-161. [PMID: 31987662 DOI: 10.1016/j.tips.2019.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 12/18/2019] [Accepted: 12/30/2019] [Indexed: 12/20/2022]
Abstract
Tetrahydroprotoberberines (THPBs) are a class of compounds that target both dopamine D1 and D2 families of receptors, making them attractive candidates for treating substance use disorder (SUD). The binding of some THPBs to serotonin and adrenergic receptors, in addition to dopamine receptors, gives rise to complex pharmacological profiles. Significant progress has been made over the last decade in examining these compounds for their therapeutic potential. Here, we evaluate recent discoveries relating to the neural mechanism and therapeutic effects of THPBs, focusing on compounds that have shown promise in animal models of SUD and preliminary clinical studies. Advancements in structure-activity relationship studies and in silico modeling of THPB binding to dopamine receptors have facilitated the synthesis of novel THPBs with enhanced therapeutic properties and provide insights regarding use of the THPB scaffold to serve as a template for innovative drug designs.
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Affiliation(s)
- Maya O Nesbit
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 3402-2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Anthony G Phillips
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 3402-2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.
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Scott GA, Roebuck AJ, Greba Q, Howland JG. Performance of the trial-unique, delayed non-matching-to-location (TUNL) task depends on AMPA/Kainate, but not NMDA, ionotropic glutamate receptors in the rat posterior parietal cortex. Neurobiol Learn Mem 2019; 159:16-23. [DOI: 10.1016/j.nlm.2019.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/04/2018] [Accepted: 02/03/2019] [Indexed: 02/06/2023]
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Winship IR, Dursun SM, Baker GB, Balista PA, Kandratavicius L, Maia-de-Oliveira JP, Hallak J, Howland JG. An Overview of Animal Models Related to Schizophrenia. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2019; 64:5-17. [PMID: 29742910 PMCID: PMC6364139 DOI: 10.1177/0706743718773728] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Schizophrenia is a heterogeneous psychiatric disorder that is poorly treated with current therapies. In this brief review, we provide an update regarding the use of animal models to study schizophrenia in an attempt to understand its aetiology and develop novel therapeutic strategies. Tremendous progress has been made developing and validating rodent models that replicate the aetiologies, brain pathologies, and behavioural abnormalities associated with schizophrenia in humans. Here, models are grouped into 3 categories-developmental, drug induced, and genetic-to reflect the heterogeneous risk factors associated with schizophrenia. Each of these models is associated with varied but overlapping pathophysiology, endophenotypes, behavioural abnormalities, and cognitive impairments. Studying schizophrenia using multiple models will permit an understanding of the core features of the disease, thereby facilitating preclinical research aimed at the development and validation of better pharmacotherapies to alter the progression of schizophrenia or alleviate its debilitating symptoms.
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Affiliation(s)
- Ian R Winship
- 1 Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta
| | - Serdar M Dursun
- 2 Department of Psychiatry, Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta.,3 National Institute of Science and Technology-Translational Science, Brazil
| | - Glen B Baker
- 2 Department of Psychiatry, Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta.,3 National Institute of Science and Technology-Translational Science, Brazil
| | - Priscila A Balista
- 4 Department of Pharmacy, Centro Universitario das Faculdades Metropolitanas Unidas, São Paulo, Brazil
| | - Ludmyla Kandratavicius
- 5 Department of Neuroscience and Behavior, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil
| | - Joao Paulo Maia-de-Oliveira
- 3 National Institute of Science and Technology-Translational Science, Brazil.,6 Department of Clinical Medicine, Rio Grande do Norte Federal University, Natal, Brazil
| | - Jaime Hallak
- 3 National Institute of Science and Technology-Translational Science, Brazil.,5 Department of Neuroscience and Behavior, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil.,7 Department of Psychiatry (NRU), University of Alberta, Edmonton, Alberta
| | - John G Howland
- 8 Department of Physiology, University of Saskatchewan, Saskatoon, Saskatchewan
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Effects of the T-type calcium channel antagonist Z944 on paired associates learning and locomotor activity in rats treated with the NMDA receptor antagonist MK-801. Psychopharmacology (Berl) 2018; 235:3339-3350. [PMID: 30251162 DOI: 10.1007/s00213-018-5040-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 09/14/2018] [Indexed: 12/12/2022]
Abstract
RATIONALE Currently available antipsychotics are unsatisfactory given their side effects and limited efficacy for the cognitive symptoms of schizophrenia. Many currently available drugs, such as haloperidol, are T-type calcium channel antagonists in addition to their well-established antagonism of dopamine D2 receptors. Thus, preclinical research into the effects of T-type calcium channel antagonists/blockers in behavioral assays related to schizophrenia may inform novel therapeutic strategies. OBJECTIVES We explored the effects of a recently developed highly selective T-type calcium channel antagonist, Z944 (2.5, 5.0, 10.0 mg/kg), on the MK-801 (0.15 mg/kg) model of acute psychosis. METHODS To examine the effects of Z944 on behaviors relevant to schizophrenia, we tested touchscreen-based paired associates learning given its relevance to the cognitive symptoms of the disorder and locomotor activity given its relevance to the positive symptoms. RESULTS Acute treatment with Z944 failed to reverse the visuospatial associative memory impairments caused by MK-801 in paired associates learning. The highest dose of drug (10.0 mg/kg) given alone produced subtle impairments on paired associates learning. In contrast, Z944 (5.0 mg/kg) blocked the expected increase in locomotion following MK-801 treatment in a locomotor assay. CONCLUSIONS These experiments provide support that Z944 may reduce behaviors relevant to positive symptoms of schizophrenia, although additional study of its effects on cognition is required. These findings and other research suggest T-type calcium channel antagonists may be an alternative to currently available antipsychotics with less serious side effects.
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11
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Roebuck AJ, Liu MC, Lins BR, Scott GA, Howland JG. Acute stress, but not corticosterone, facilitates acquisition of paired associates learning in rats using touchscreen-equipped operant conditioning chambers. Behav Brain Res 2018; 348:139-149. [PMID: 29684470 DOI: 10.1016/j.bbr.2018.04.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/13/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022]
Abstract
Acute stress influences learning and memory in humans and rodents, enhancing performance in some tasks while impairing it in others. Typically, subjects preferentially employ striatal-mediated stimulus-response strategies in spatial memory tasks following stress, making use of fewer hippocampal-based strategies which may be more cognitively demanding. Previous research demonstrated that the acquisition of rodent paired associates learning (PAL) relies primarily on the striatum, while task performance after extensive training is impaired by hippocampal disruption. Therefore, we sought to explore whether the acquisition of PAL, an operant conditioning task involving spatial stimuli, could be enhanced by acute stress. Male Long-Evans rats were trained to a predefined criterion in PAL and then subjected to either a single session of restraint stress (30 min) or injection of corticosterone (CORT; 3 mg/kg). Subsequent task performance was monitored for one week. We found that rats subjected to restraint stress, but not those rats injected with CORT, performed with higher accuracy and efficiency, when compared to untreated controls. These results suggest that while acute stress enhances the acquisition of PAL, CORT alone does not. This dissociation may be due to differences between these treatments and their ability to produce sufficient catecholamine release in the amygdala, a requirement for stress effects on memory.
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Affiliation(s)
- Andrew J Roebuck
- Department of Physiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Max C Liu
- Department of Physiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Brittney R Lins
- Department of Physiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Gavin A Scott
- Department of Physiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - John G Howland
- Department of Physiology, University of Saskatchewan, Saskatoon, SK, Canada.
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12
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Dauvermann MR, Lee G, Dawson N. Glutamatergic regulation of cognition and functional brain connectivity: insights from pharmacological, genetic and translational schizophrenia research. Br J Pharmacol 2017. [PMID: 28626937 DOI: 10.1111/bph.13919] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The pharmacological modulation of glutamatergic neurotransmission to improve cognitive function has been a focus of intensive research, particularly in relation to the cognitive deficits seen in schizophrenia. Despite this effort, there has been little success in the clinical use of glutamatergic compounds as procognitive drugs. Here, we review a selection of the drugs used to modulate glutamatergic signalling and how they impact on cognitive function in rodents and humans. We highlight how glutamatergic dysfunction, and NMDA receptor hypofunction in particular, is a key mechanism contributing to the cognitive deficits observed in schizophrenia and outline some of the glutamatergic targets that have been tested as putative procognitive targets for this disorder. Using translational research in this area as a leading exemplar, namely, models of NMDA receptor hypofunction, we discuss how the study of functional brain network connectivity can provide new insight into how the glutamatergic system impacts on cognitive function. Future studies characterizing functional brain network connectivity will increase our understanding of how glutamatergic compounds regulate cognition and could contribute to the future success of glutamatergic drug validation. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc.
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Affiliation(s)
- Maria R Dauvermann
- School of Psychology, National University of Ireland, Galway, Ireland.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Graham Lee
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Neil Dawson
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, UK
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13
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Lins BR, Marks WN, Phillips AG, Howland JG. Dissociable effects of the d- and l- enantiomers of govadine on the disruption of prepulse inhibition by MK-801 and apomorphine in male Long-Evans rats. Psychopharmacology (Berl) 2017; 234:1079-1091. [PMID: 28180960 DOI: 10.1007/s00213-017-4540-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 01/23/2017] [Indexed: 01/02/2023]
Abstract
RATIONALE The search for novel antipsychotic drugs to treat schizophrenia is driven by the poor treatment efficacy, serious side effects, and poor patient compliance of current medications. Recently, a class of compounds known as tetrahydroprotoberberines, which includes the compound d,l-govadine, have shown promise in preclinical rodent tests relevant to schizophrenia. To date, the effect of govadine on prepulse inhibition (PPI), a test for sensorimotor gating commonly used to assess the effects of putative treatments for schizophrenia, has not been determined. OBJECTIVES The objective of the present study was to determine the effects of each enantiomer of govadine (d- and l-govadine) on PPI alone and its disruption by the distinct pharmacological compounds apomorphine and MK-801. METHODS Male Long-Evans rats were treated systemically with d- or l-govadine and apomorphine or MK-801 prior to PPI. The PPI paradigm employed here included parametric manipulations of the prepulse intensity and the interval between the prepulse and pulse. RESULTS Acute MK-801 (0.15 mg/kg) significantly increased the startle response to startle pulses alone, while both MK-801 and apomorphine (0.2 mg/kg) significantly increased reactivity to prepulse-alone trials. Both MK-801 and apomorphine disrupted PPI. In addition, d-govadine alone significantly disrupted PPI in the apomorphine experiment. Pretreatment with l-, but not d-, govadine (1.0 mg/kg) blocked the effect of apomorphine and MK-801 on PPI. Treatment of rats with l-govadine alone (0.3, 1.0, 3.0 mg/kg) also dose-dependently increased PPI. CONCLUSIONS Given the high affinity of l-govadine for dopamine D2 receptors, these results suggest that further testing of l-govadine as an antipsychotic is warranted.
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Affiliation(s)
- Brittney R Lins
- Department of Physiology, University of Saskatchewan, GD30.7, Health Sciences Building, 107 Wiggins Rd, Saskatoon, SK, S7N 5E5, Canada
| | - Wendie N Marks
- Department of Physiology, University of Saskatchewan, GD30.7, Health Sciences Building, 107 Wiggins Rd, Saskatoon, SK, S7N 5E5, Canada
| | - Anthony G Phillips
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - John G Howland
- Department of Physiology, University of Saskatchewan, GD30.7, Health Sciences Building, 107 Wiggins Rd, Saskatoon, SK, S7N 5E5, Canada.
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MK-801-induced impairments on the trial-unique, delayed nonmatching-to-location task in rats: effects of acute sodium nitroprusside. Psychopharmacology (Berl) 2017; 234:211-222. [PMID: 27725997 DOI: 10.1007/s00213-016-4451-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 09/25/2016] [Indexed: 12/13/2022]
Abstract
RATIONALE The cognitive symptoms observed in schizophrenia are not consistently alleviated by conventional antipsychotics. Following a recent pilot study, sodium nitroprusside (SNP) has been identified as a promising adjunct treatment to reduce the working memory impairments experienced by schizophrenia patients. OBJECTIVE The present experiments were designed to explore the effects of SNP on the highly translatable trial-unique, delayed nonmatching-to-location (TUNL) task in rats with and without acute MK-801 treatment. METHODS SNP (0.5, 1.0, 2.0, 4.0, and 5.0 mg/kg) and MK-801 (0.05, 0.075, and 0.1 mg/kg) were acutely administered to rats trained on the TUNL task. RESULTS Acute MK-801 treatment impaired TUNL task accuracy. Administration of SNP (2.0 mg/kg) with MK-801 (0.1 mg/kg) failed to rescue performance on TUNL. SNP (5.0 mg/kg) administration nearly 4 h prior to MK-801 (0.05 mg/kg) treatment had no preventative effect on performance impairments. SNP (2.0 mg/kg) improved performance on a subset of trials. CONCLUSION These results suggest that SNP may possess intrinsic cognitive-enhancing properties but is unable to block the effects of acute MK-801 treatment on the TUNL task. These results are inconsistent with the effectiveness of SNP as an adjunct therapy for working memory impairments in schizophrenia patients. Future studies in rodents that assess SNP as an adjunct therapy will be valuable in understanding the mechanisms underlying the effectiveness of SNP as a treatment for schizophrenia.
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Madapa S, Gadhiya S, Kurtzman T, Alberts IL, Ramsey S, Reith M, Harding WW. Synthesis and evaluation of C9 alkoxy analogues of (-)-stepholidine as dopamine receptor ligands. Eur J Med Chem 2016; 125:255-268. [PMID: 27688181 DOI: 10.1016/j.ejmech.2016.09.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/09/2016] [Accepted: 09/10/2016] [Indexed: 01/01/2023]
Abstract
Tetrahydroprotoberberine alkaloids have shown interesting polypharmacological actions at dopamine receptors and are a unique template from which to mine novel molecules with dual selective actions at D1 and D3 receptors. Such compounds will be valuable to evaluate as anti-cocaine therapeutics. Towards that eventual goal, we engaged an SAR study in which a series of C9 alkoxy analogues of the D1/D2/D3 ligand (-)-stepholidine that possessed or lacked a C12 bromo functionality, were synthesized and evaluated for affinity at dopamine D1, D2 and D3 receptors. We found that the analogues are generally selective for the D1 receptor. Small n-alkoxy substituents (up to 4 carbons in length) were generally well tolerated for high D1 affinity but such groups reduced D3 affinity. In the case of C12 brominated analogues, C9 alkoxylation also had little effect on D1 affinity for the smaller alkoxy groups, but reduced D2 and D3 affinities significantly. C12 bromination tends to increase D1 receptor selectivity. A number of compounds were identified that retain affinity for D1 and D3 receptors but lack D2 receptor affinity. Among them, compound 22a was found to be a selective D1/D3 dual antagonist (Ki = 5.3 and 106 nM at D1 and D3 receptors). Docking studies performed on the analogues at the D3 receptor revealed a number of interactions that are important for affinity including a critical N - Asp110 salt bridge motif, H-bonds to Ser192 and Cys181 and hydrophobic interactions between the aryl rings and Phe106 and Phe345. The analogues adopt an orientation in which ring A is located in the orthosteric binding site while the C9 alkoxy substituents attached to ring D project into the secondary binding pocket of the D3 receptor.
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Affiliation(s)
- Sudharshan Madapa
- Department of Chemistry, Hunter College, City University of New York, 695 Park Avenue, NY 10065, USA
| | - Satishkumar Gadhiya
- Department of Chemistry, Hunter College, City University of New York, 695 Park Avenue, NY 10065, USA; Ph.D. Program in Chemistry, CUNY Graduate Center, 365 5th Avenue, New York, NY 10016, USA
| | - Thomas Kurtzman
- Ph.D. Program in Chemistry, CUNY Graduate Center, 365 5th Avenue, New York, NY 10016, USA; Ph.D. Program in Biochemistry, CUNY Graduate Center, 365 5th Avenue, New York, NY 10016, USA; Department of Chemistry, Lehman College, The City University of New York, Bronx, NY 10468, USA
| | - Ian L Alberts
- Department of Natural Sciences, LaGuardia Community College, City University of New York, New York, NY 11101, USA
| | - Steven Ramsey
- Ph.D. Program in Biochemistry, CUNY Graduate Center, 365 5th Avenue, New York, NY 10016, USA; Department of Chemistry, Lehman College, The City University of New York, Bronx, NY 10468, USA
| | - Maarten Reith
- Department of Psychiatry, New York University, New York, NY 10016, USA
| | - Wayne W Harding
- Department of Chemistry, Hunter College, City University of New York, 695 Park Avenue, NY 10065, USA; Ph.D. Program in Chemistry, CUNY Graduate Center, 365 5th Avenue, New York, NY 10016, USA; Ph.D. Program in Biochemistry, CUNY Graduate Center, 365 5th Avenue, New York, NY 10016, USA.
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Lins BR, Howland JG. Effects of the metabotropic glutamate receptor 5 positive allosteric modulator CDPPB on rats tested with the paired associates learning task in touchscreen-equipped operant conditioning chambers. Behav Brain Res 2015; 301:152-60. [PMID: 26721467 DOI: 10.1016/j.bbr.2015.12.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/30/2015] [Accepted: 12/17/2015] [Indexed: 02/03/2023]
Abstract
Effective treatments for the cognitive symptoms of schizophrenia are critically needed. Positive allosteric modulation (PAM) of metabotropic glutamate receptor subtype 5 (mGluR5) is one strategy currently under investigation to improve these symptoms. Examining cognition using touchscreen-equipped operant chambers may increase translation between preclinical and clinical research through analogous behavioral testing paradigms in rodents and humans. We used acute CDPPB (1-30mg/kg) treatment to examine the effects of mGluR5 PAM in the touchscreen paired associates learning (PAL) task using well-trained rats with and without co-administration of acute MK-801 (0.15mg/kg). CDPPB had no consistent effects on task performance when administered alone and failed to reverse the MK-801 induced impairments at any of the examined doses. Overall, the disruptive effects of MK-801 on PAL were consistent with previous research but increasing mGluR5 signaling is not beneficial in the PAL task. Future research should test whether administration of CDPPB during PAL acquisition increases performance.
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Affiliation(s)
- Brittney R Lins
- Department of Physiology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - John G Howland
- Department of Physiology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
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