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Wolf CJH, Spoelder M, Beurmanjer H, Bulthuis R, Schellekens AFA, Homberg JR. Individual differences in GHB consumption in a new voluntary GHB self-administration model in outbred rats. Psychopharmacology (Berl) 2024; 241:613-625. [PMID: 38334790 PMCID: PMC10884067 DOI: 10.1007/s00213-024-06537-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 01/17/2024] [Indexed: 02/10/2024]
Abstract
BACKGROUND AND PURPOSE The use of the recreational drug gamma-hydroxybutyric acid (GHB) has increased over the past decade, concomitantly leading to a higher incidence of GHB use disorder. Evidence-based treatment interventions are hardly available and cognitive effects of long-term GHB use remain elusive. In order to study the development of GUD and the causal effects of chronic GHB consumption, a GHB self-administration model is required. EXPERIMENTAL APPROACH Long Evans rats had access to GHB in their home cage according to a two-bottle choice procedure for 3 months. Intoxication and withdrawal symptoms were assessed using an automated sensor-based setup for longitudinal behavioral monitoring. Rats were trained in an operant environment according to a fixed ratio (FR) 1, 2, and 4 schedule of reinforcement. Addiction-like behaviors were assessed through progressive ratio-, non-reinforced-, and quinine-adulterated operant tests. In addition, the novel object recognition test and elevated plus maze test were performed before and after GHB self-administration to assess memory performance and anxiety-like behavior, respectively. KEY RESULTS All rats consumed pharmacologically relevant levels of GHB in their home cage, and their intake remained stable over a period of 3 months. No clear withdrawal symptoms were observed following abstinence. Responding under operant conditions was characterized by strong inter-individual differences, where only a subset of rats showed high motivation for GHB, habitual GHB-seeking, and/or continued responding for GHB despite an aversive taste. Male rats showed a reduction in long-term memory performance 3 months after home-cage GHB self-administration. Anxiety-like behavior was not affected by GHB self-administration. CONCLUSION AND IMPLICATIONS The GHB self-administration model was able to reflect individual susceptibility for addiction-like behavior. The reduction in long-term memory performance upon GHB self-administration calls for further research into the cognitive effects of chronic GHB use in humans.
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Affiliation(s)
- Casper J H Wolf
- Donders Institute for Brain, Department of Psychiatry, Radboudumc, Cognition, and Behaviour, Reinier Postlaan 4, 6525 GC, Nijmegen, The Netherlands.
- Donders Institute for Brain Cognition and Behaviour, Department of Cognitive Neuroscience, Radboudumc, 6525 EN, Nijmegen, The Netherlands.
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), 6525 HR, Nijmegen, The Netherlands.
| | - Marcia Spoelder
- Department of Primary and Community Care, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
| | - Harmen Beurmanjer
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), 6525 HR, Nijmegen, The Netherlands
- Behavioural Science Institute, Radboud University, 6525 GD, Nijmegen, The Netherlands
- Novadic-Kentron Addiction Care, 5261 LX, Vught, The Netherlands
| | | | - Arnt F A Schellekens
- Donders Institute for Brain, Department of Psychiatry, Radboudumc, Cognition, and Behaviour, Reinier Postlaan 4, 6525 GC, Nijmegen, The Netherlands
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), 6525 HR, Nijmegen, The Netherlands
| | - Judith R Homberg
- Donders Institute for Brain Cognition and Behaviour, Department of Cognitive Neuroscience, Radboudumc, 6525 EN, Nijmegen, The Netherlands
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Blokland A, Sesia T. Delay-dependent forgetting in object recognition and object location test is dependent on strain and test. Behav Brain Res 2023; 437:114161. [PMID: 36257558 DOI: 10.1016/j.bbr.2022.114161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/01/2022] [Accepted: 10/12/2022] [Indexed: 11/06/2022]
Abstract
The object recognition and object location task (ORT and OLT, respectively) have been applied in preclinical research to evaluate the effects of treatments on memory. Although both tasks look quite similar, they differ with respect to the brain structures involved in the memory performance. The characterization of the memory performance in both tasks is important to understand treatment effects. Since there are no previous studies that compared strain differences in delay-dependent forgetting in both tasks, Wistar and Long Evans rats were tested in both the ORT and the OLT at different intervals. The data showed that in the ORT the delay-dependent forgetting was similar for Wistar and Long Evans rats. However, the forgetting curve was different for both strains in the OLT: the Long Evans rats the forgetting took a longer interval. This study indicates that delay-dependent forgetting in the ORT and OLT is strain and test dependent. It is suggested that before testing treatments the forgetting curve of a specific strain should be tested in this type of tasks.
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Affiliation(s)
- Arjan Blokland
- Faculty of Psychology and Neuroscience, Department of Neuropsychology & Psychopharmacology, EURON, Maastricht University, the Netherlands; European Graduate School of Neuroscience (EURON), the Netherlands.
| | - Thibaut Sesia
- Department of Stereotactic and Functional Neurosurgery, University Hospital Cologne, Cologne, Germany; European Graduate School of Neuroscience (EURON), the Netherlands
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Lallai V, Manca L, Sherafat Y, Fowler CD. Effects of Prenatal Nicotine, THC, or Co-Exposure on Cognitive Behaviors in Adolescent Male and Female Rats. Nicotine Tob Res 2022; 24:1150-1160. [PMID: 35090174 PMCID: PMC9278841 DOI: 10.1093/ntr/ntac018] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/26/2021] [Accepted: 01/26/2022] [Indexed: 01/30/2023]
Abstract
INTRODUCTION Although there has been a decrease in the prevalence of tobacco smoking, exposure to nicotine during pregnancy remains a substantial problem worldwide. Further, given the recent escalation in e-cigarette use and legalization of cannabis, it has become essential to understand the effects of nicotine and cannabinoid co-exposure during early developmental stages. AIMS AND METHODS We systematically examined the effects of nicotine and/or THC prenatal exposure on cognitive behaviors in male and female offspring. Dams were exposed to nicotine vape or vehicle, and oral edible THC or vehicle, throughout pregnancy. Adolescent offspring were then tested in the prepulse inhibition test, novel object recognition task, and novelty suppressed feeding task. RESULTS At birth, pups from mothers exposed to nicotine vape or oral THC exhibited reduced body weight, compared to control pups. Prenatal nicotine vape exposure resulted in a decreased baseline startle reactivity in adolescent male and female rats, and in females, enhanced sensorimotor gating in the prepulse inhibition test. Prenatal nicotine and THC co-exposure resulted in significant deficits in the prepulse inhibition test in males. Deficits in short-term memory were also found in males prenatally exposed to THC, either alone or with nicotine co-exposure, and in females exposed to THC alone. Finally, in males, a modest increase in anxiety-associated behaviors was found with THC or nicotine exposure in the latency to approach a novel palatable food. CONCLUSIONS These studies demonstrate differential effects of prenatal exposure to e-cigarette nicotine vape and/or edible THC on cognitive function, with differing effects within male and female groups. IMPLICATIONS These studies demonstrate an impact of nicotine, THC, or co-exposure during early developmental stages in utero on behavioral outcomes in adolescence. These findings have important translational implications given the continued use of nicotine and THC containing products by pregnant women worldwide, which can be applied to support healthcare and policy efforts restricting nicotine and THC use during pregnancy.
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Affiliation(s)
- Valeria Lallai
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697, USA
| | - Letizia Manca
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697, USA
| | - Yasmine Sherafat
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697, USA
| | - Christie D Fowler
- Corresponding Author: Christie D. Fowler, PhD, Department of Neurobiology and Behavior, University of California Irvine, 1232 McGaugh Hall, Irvine, CA 92697-4550, USA. Telephone: 949-824-8363; Fax: 949-824-2447; E-mail:
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Pharmacological inhibition of phosphodiesterase 7 enhances consolidation processes of spatial memory. Neurobiol Learn Mem 2020; 177:107357. [PMID: 33278592 DOI: 10.1016/j.nlm.2020.107357] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/23/2020] [Accepted: 11/30/2020] [Indexed: 12/26/2022]
Abstract
Augmentation of cAMP signaling through inhibition of phosphodiesterases (PDE) is known to enhance plasticity and memory. Inhibition of PDE4 enhances consolidation into memory, but less is known about the role of other cAMP specific PDEs. Here, we tested the effects of oral treatment with a selective inhibitor of PDE7 of nanomolar potency on spatial and contextual memory. In an object location task, doses of 0.3-3 mg/kg administered 3 h after training dose-dependently attenuated time-dependent forgetting in rats. Significant enhancement of memory occurred at a dose of 3 mg/kg with corresponding brain levels consistent with PDE7 inhibition. The same dose given prior to training augmented contextual fear conditioning. In mice, daily dosing before training enhanced spatial memory in two different incremental learning paradigms in the Barnes Maze. Drug treated mice made significantly less errors locating the escape in a probe-test 24 h after the end of training, and they exhibited hippocampal-dependent spatial search strategies more frequently than controls, which tended to show serial sampling of escape locations. Acquisition and short-term memory, in contrast, were unaffected. Our data provide evidence for a role of PDE7 in the consolidation of hippocampal-dependent memory. We suggest that targeting PDE7 for memory enhancement may provide an alternative to PDE4 inhibitors, which tend to have undesirable gastrointestinal side-effects.
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Kelly MP, Heckman PRA, Havekes R. Genetic manipulation of cyclic nucleotide signaling during hippocampal neuroplasticity and memory formation. Prog Neurobiol 2020; 190:101799. [PMID: 32360536 DOI: 10.1016/j.pneurobio.2020.101799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/14/2020] [Accepted: 03/26/2020] [Indexed: 12/12/2022]
Abstract
Decades of research have underscored the importance of cyclic nucleotide signaling in memory formation and synaptic plasticity. In recent years, several new genetic techniques have expanded the neuroscience toolbox, allowing researchers to measure and modulate cyclic nucleotide gradients with high spatiotemporal resolution. Here, we will provide an overview of studies using genetic approaches to interrogate the role cyclic nucleotide signaling plays in hippocampus-dependent memory processes and synaptic plasticity. Particular attention is given to genetic techniques that measure real-time changes in cyclic nucleotide levels as well as newly-developed genetic strategies to transiently manipulate cyclic nucleotide signaling in a subcellular compartment-specific manner with high temporal resolution.
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Affiliation(s)
- Michy P Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Rd, VA Bldg1, 3(rd) Fl, D-12, Columbia, 29209, SC, USA.
| | - Pim R A Heckman
- Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
| | - Robbert Havekes
- Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
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The medial prefrontal cortex - hippocampus circuit that integrates information of object, place and time to construct episodic memory in rodents: Behavioral, anatomical and neurochemical properties. Neurosci Biobehav Rev 2020; 113:373-407. [PMID: 32298711 DOI: 10.1016/j.neubiorev.2020.04.007] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/25/2020] [Accepted: 04/06/2020] [Indexed: 12/31/2022]
Abstract
Rats and mice have been demonstrated to show episodic-like memory, a prototype of episodic memory, as defined by an integrated memory of the experience of an object or event, in a particular place and time. Such memory can be assessed via the use of spontaneous object exploration paradigms, variably designed to measure memory for object, place, temporal order and object-location inter-relationships. We review the methodological properties of these tests, the neurobiology about time and discuss the evidence for the involvement of the medial prefrontal cortex (mPFC), entorhinal cortex (EC) and hippocampus, with respect to their anatomy, neurotransmitter systems and functional circuits. The systematic analysis suggests that a specific circuit between the mPFC, lateral EC and hippocampus encodes the information for event, place and time of occurrence into the complex episodic-like memory, as a top-down regulation from the mPFC onto the hippocampus. This circuit can be distinguished from the neuronal component memory systems for processing the individual information of object, time and place.
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Pilarzyk K, Klett J, Pena EA, Porcher L, Smith AJ, Kelly MP. Loss of Function of Phosphodiesterase 11A4 Shows that Recent and Remote Long-Term Memories Can Be Uncoupled. Curr Biol 2019; 29:2307-2321.e5. [PMID: 31303492 DOI: 10.1016/j.cub.2019.06.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 03/06/2019] [Accepted: 06/07/2019] [Indexed: 12/19/2022]
Abstract
Systems consolidation is a process by which memories initially require the hippocampus for recent long-term memory (LTM) but then become increasingly independent of the hippocampus and more dependent on the cortex for remote LTM. Here, we study the role of phosphodiesterase 11A4 (PDE11A4) in systems consolidation. PDE11A4, which degrades cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), is preferentially expressed in neurons of CA1, the subiculum, and the adjacently connected amygdalohippocampal region. In male and female mice, deletion of PDE11A enhances remote LTM for social odor recognition and social transmission of food preference (STFP) despite eliminating or silencing recent LTM for those same social events. Measurement of a surrogate marker of neuronal activation (i.e., Arc mRNA) suggests the recent LTM deficits observed in Pde11 knockout mice correspond with decreased activation of ventral CA1 relative to wild-type littermates. In contrast, the enhanced remote LTM observed in Pde11a knockout mice corresponds with increased activation and altered functional connectivity of anterior cingulate cortex, frontal association cortex, parasubiculum, and the superficial layer of medial entorhinal cortex. The apparent increased neural activation observed in prefrontal cortex of Pde11a knockout mice during remote LTM retrieval may be related to an upregulation of the N-methyl-D-aspartate receptor subunits NR1 and NR2A. Viral restoration of PDE11A4 to vCA1 alone is sufficient to rescue both the LTM phenotypes and upregulation of NR1 exhibited by Pde11a knockout mice. Together, our findings suggest remote LTM can be decoupled from recent LTM, which may have relevance for cognitive deficits associated with aging, temporal lobe epilepsy, or transient global amnesia.
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Affiliation(s)
- Katy Pilarzyk
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC 29209, USA
| | - Jennifer Klett
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC 29209, USA
| | - Edsel A Pena
- Department of Statistics, University of South Carolina, 1523 Green Street, Columbia, SC 29201, USA
| | - Latarsha Porcher
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC 29209, USA
| | - Abigail J Smith
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC 29209, USA
| | - Michy P Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC 29209, USA.
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Lueptow LM. Novel Object Recognition Test for the Investigation of Learning and Memory in Mice. J Vis Exp 2017. [PMID: 28892027 DOI: 10.3791/55718] [Citation(s) in RCA: 301] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The object recognition test (ORT) is a commonly used behavioral assay for the investigation of various aspects of learning and memory in mice. The ORT is fairly simple and can be completed over 3 days: habituation day, training day, and testing day. During training, the mouse is allowed to explore 2 identical objects. On test day, one of the training objects is replaced with a novel object. Because mice have an innate preference for novelty, if the mouse recognizes the familiar object, it will spend most of its time at the novel object. Due to this innate preference, there is no need for positive or negative reinforcement or long training schedules. Additionally, the ORT can also be modified for numerous applications. The retention interval can be shortened to examine short-term memory, or lengthened to probe long-term memory. Pharmacological intervention can be used at various times prior to training, after training, or prior to recall to investigate different phases of learning (i.e., acquisition, early or late consolidation, or recall). Overall, the ORT is a relatively low-stress, efficient test for memory in mice, and is appropriate for the detection of neuropsychological changes following pharmacological, biological, or genetic manipulations.
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Lueptow LM, Zhan CG, O'Donnell JM. Cyclic GMP-mediated memory enhancement in the object recognition test by inhibitors of phosphodiesterase-2 in mice. Psychopharmacology (Berl) 2016; 233:447-56. [PMID: 26525565 DOI: 10.1007/s00213-015-4129-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/14/2015] [Indexed: 12/24/2022]
Abstract
RATIONALE AND OBJECTIVES Cyclic nucleotide phosphodiesterase-2 (PDE2) is a potential therapeutic target for the treatment of cognitive dysfunction. Using the object recognition test (ORT), this study assessed the effects of two PDE2 inhibitors, Bay 60-7550 and ND7001, on learning and memory, and examined underlying mechanisms. METHODS To assess the role of PDE2 inhibition on phases of memory, Bay 60-7550 (3 mg/kg) was administered: 30 min prior to training; 0, 1, or 3 h after training; or 30 min prior to recall testing. To assess cyclic nucleotide involvement in PDE2 inhibitor-enhanced memory consolidation, either the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 20 mg/kg; intraperitoneal (IP)), soluble guanylyl cyclase inhibitor 1H-[-1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ; 20 mg/kg; IP), protein kinase G inhibitor KT5823 (2.5 μg; intracerebroventricular (ICV)), or protein kinase A inhibitor H89 (1 μg; ICV) was administered 30 min prior to the PDE2 inhibitor Bay 60-7550 (3 mg/kg) or ND7001 (3 mg/kg). Changes in the phosphorylation of 3'5'-cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) at Ser-133 and vasodilator-stimulated phosphoprotein (VASP) at Ser-239 were determined to confirm activation of cAMP and 3'5'-cyclic guanosine monophosphate (cGMP) signaling. RESULTS Bay 60-7550 (3 mg/kg) enhanced memory of mice in the ORT when given 30 min prior to training, immediately after training, or 30 min prior to recall. Inhibitors of the cGMP pathway blocked the memory-enhancing effects of both Bay 60-7550 (3 mg/kg) and ND7001 (3 mg/kg) on early consolidation processes. Bay 60-7550 (3 mg/kg) enhanced phosphorylation of CREB and VASP, both targets of cGMP-dependent protein kinase (PKG). CONCLUSIONS These results confirm a potential of PDE2, or components of its signaling pathway, as a therapeutic target for drug discovery focused on restoring memory function.
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Affiliation(s)
- Lindsay M Lueptow
- Neuroscience Graduate Program, West Virginia University Health Sciences Center, Morgantown, WV, USA.
- West Virginia University, 1 Medical Center Drive, PO Box 9128, Morgantown, WV, USA.
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA
| | - James M O'Donnell
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
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Akkerman S, Blokland A, Prickaerts J. Possible overlapping time frames of acquisition and consolidation phases in object memory processes: a pharmacological approach. ACTA ACUST UNITED AC 2015; 23:29-37. [PMID: 26670184 PMCID: PMC4749836 DOI: 10.1101/lm.040162.115] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/03/2015] [Indexed: 02/03/2023]
Abstract
In previous studies, we have shown that acetylcholinesterase inhibitors and phosphodiesterase inhibitors (PDE-Is) are able to improve object memory by enhancing acquisition processes. On the other hand, only PDE-Is improve consolidation processes. Here we show that the cholinesterase inhibitor donepezil also improves memory performance when administered within 2 min after the acquisition trial. Likewise, both PDE5-I and PDE4-I reversed the scopolamine deficit model when administered within 2 min after the learning trial. PDE5-I was effective up to 45 min after the acquisition trial and PDE4-I was effective when administered between 3 and 5.5 h after the acquisition trial. Taken together, our study suggests that acetylcholine, cGMP, and cAMP are all involved in acquisition processes and that cGMP and cAMP are also involved in early and late consolidation processes, respectively. Most important, these pharmacological studies suggest that acquisition processes continue for some time after the learning trial where they share a short common time frame with early consolidation processes. Additional brain concentration measurements of the drugs suggest that these acquisition processes can continue up to 4-6 min after learning.
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Affiliation(s)
- Sven Akkerman
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, European Graduate School of Neuroscience
| | - Arjan Blokland
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, European Graduate School of Neuroscience, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, European Graduate School of Neuroscience
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Abstract
Cyclic adenosine monophosphate (cAMP) is one of the second messengers critically involved in the molecular mechanisms underlying memory formation. In the CNS, the availability of cAMP is tightly controlled by phosphodiesterase 4 (PDE4), a family of enzymes that degrades the cyclic nucleotide to inactive AMP. Among the different PDE4 isoforms, in the last few years PDE4D has been hogging the limelight due to accumulating evidence for its crucial role in cognitive processes, which makes this enzyme a promising target for therapeutic interventions in a variety of pathological conditions characterized by memory impairment, such as Alzheimer's disease. In this article, we review the role of the cAMP signal transduction pathway in memory formation with a particular focus on the recent progress in PDE4D research.
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Affiliation(s)
- Roberta Ricciarelli
- Department of Experimental Medicine, Section of General Pathology, University of Genoa, Genoa, Italy
| | - Ernesto Fedele
- Department of Pharmacy, Section of Pharmacology and Toxicology, Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
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Brodziak A, Kołat E, Różyk-Myrta A. In search of memory tests equivalent for experiments on animals and humans. Med Sci Monit 2014; 20:2733-9. [PMID: 25524993 PMCID: PMC4280055 DOI: 10.12659/msm.891056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Older people often exhibit memory impairments. Contemporary demographic trends cause aging of the society. In this situation, it is important to conduct clinical trials of drugs and use training methods to improve memory capacity. Development of new memory tests requires experiments on animals and then clinical trials in humans. Therefore, we decided to review the assessment methods and search for tests that evaluate analogous cognitive processes in animals and humans. This review has enabled us to propose 2 pairs of tests of the efficiency of working memory capacity in animals and humans. We propose a basic set of methods for complex clinical trials of drugs and training methods to improve memory, consisting of 2 pairs of tests: 1) the Novel Object Recognition Test – Sternberg Item Recognition Test and 2) the Object-Location Test – Visuospatial Memory Test. We postulate that further investigations of methods that are equivalent in animals experiments and observations performed on humans are necessary.
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Affiliation(s)
- Andrzej Brodziak
- Institute of Occupational Medicine and Environmental Health, Sosnowiec, Poland
| | - Estera Kołat
- Institute of Nursing, University of Applied Sciences, Nysa, Poland
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Akkerman S, Prickaerts J, Bruder AK, Wolfs KHM, De Vry J, Vanmierlo T, Blokland A. PDE5 inhibition improves object memory in standard housed rats but not in rats housed in an enriched environment: implications for memory models? PLoS One 2014; 9:e111692. [PMID: 25372140 PMCID: PMC4221101 DOI: 10.1371/journal.pone.0111692] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 09/29/2014] [Indexed: 12/20/2022] Open
Abstract
Drug effects are usually evaluated in animals housed under maximally standardized conditions. However, it is assumed that an enriched environment (EE) more closely resembles human conditions as compared to maximally standardized laboratory conditions. In the present study, we examined the acute cognition enhancing effects of vardenafil, a PDE5 inhibitor, which stimulates protein kinase G/CREB signaling in cells, in three different groups of male Wistar rats tested in an object recognition task (ORT). Rats were either housed solitarily (SOL) or socially (SOC) under standard conditions, or socially in an EE. Although EE animals remembered object information longer in the vehicle condition, vardenafil only improved object memory in SOL and SOC animals. While EE animals had a heavier dorsal hippocampus, we found no differences between experimental groups in total cell numbers in the dentate gyrus, CA2-3 or CA1. Neither were there any differences in markers for pre- and postsynaptic density. No changes in PDE5 mRNA- and protein expression levels were observed. Basal pCREB levels were increased in EE rats only, whereas β-catenin was not affected, suggesting specific activation of the MAP kinase signaling pathway and not the AKT pathway. A possible explanation for the inefficacy of vardenafil could be that CREB signaling is already optimally stimulated in the hippocampus of EE rats. Since previous data has shown that acute PDE5 inhibition does not improve memory performance in humans, the use of EE animals could be considered as a more valid model for testing cognition enhancing drugs.
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Affiliation(s)
- Sven Akkerman
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, European School of Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, European School of Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - Ann K. Bruder
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Kevin H. M. Wolfs
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, European School of Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - Jochen De Vry
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, European School of Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - Tim Vanmierlo
- Department of Immunology and Biochemistry, Biomedical research institute, Hasselt University, Hasselt, Belgium
| | - Arjan Blokland
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, European School of Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
- * E-mail:
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