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Mello e Souza T. Unraveling molecular and system processes for fear memory. Neuroscience 2022; 497:14-29. [DOI: 10.1016/j.neuroscience.2022.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 03/02/2022] [Accepted: 03/14/2022] [Indexed: 11/26/2022]
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Szkudlarek HJ, Rodríguez-Ruiz M, Hudson R, De Felice M, Jung T, Rushlow WJ, Laviolette SR. THC and CBD produce divergent effects on perception and panic behaviours via distinct cortical molecular pathways. Prog Neuropsychopharmacol Biol Psychiatry 2021; 104:110029. [PMID: 32623021 DOI: 10.1016/j.pnpbp.2020.110029] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/12/2020] [Accepted: 06/21/2020] [Indexed: 12/17/2022]
Abstract
Clinical and pre-clinical evidence demonstrates divergent psychotropic effects of THC vs. CBD. While THC can induce perceptual distortions and anxiogenic effects, CBD displays antipsychotic and anxiolytic properties. A key brain region responsible for regulation of cognition and affect, the medial prefrontal cortex (PFC), is strongly modulated by cannabinoids, suggesting that these dissociable THC/CBD-dependent effects may involve functional and molecular interplay within the PFC. The primary aim of this study was to investigate potential interactions and molecular substrates involved in PFC-mediated effects of THC and CBD on differential cognitive and affective behavioural processing. Male Sprague Dawley rats received intra-PFC microinfusions of THC, CBD or their combination, and tested in the latent inhibition paradigm, spontaneous oddity discrimination test, elevated T-maze and open field. To identify local, drug-induced molecular modulation in the PFC, PFC samples were collected and processed with Western Blotting. Intra-PFC THC induced strong panic-like responses that were counteracted with CBD. In contrast, CBD did not affect panic-like behaviours but blocked formation of associative fear memories and impaired latent inhibition and oddity discrimination performance. Interestingly, these CBD effects were dependent upon 5-HT1A receptor transmission but not influenced by THC co-administration. Moreover, THC induced robust phosphorylation of ERK1/2 that was prevented by CBD, while CBD decreased phosphorylation of p70S6K, independently of THC. These results suggest that intra-PFC infusion of THC promotes panic-like behaviour associated with increased ERK1/2 phosphorylation. In contrast, CBD impairs perceptive functions and latent inhibition via activation of 5-HT1A receptors and reduced phosphorylation of p70S6K.
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Affiliation(s)
- Hanna J Szkudlarek
- Addiction Research Group, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada.
| | - Mar Rodríguez-Ruiz
- Addiction Research Group, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Roger Hudson
- Addiction Research Group, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Marta De Felice
- Addiction Research Group, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Tony Jung
- Addiction Research Group, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Walter J Rushlow
- Addiction Research Group, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Psychiatry. Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Steven R Laviolette
- Addiction Research Group, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada; Department of Psychiatry. Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada.
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Facilitation of fear extinction by novelty is modulated by β-adrenergic and 5-HT1A serotoninergic receptors in hippocampus. Neurobiol Learn Mem 2019; 166:107101. [DOI: 10.1016/j.nlm.2019.107101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 08/21/2019] [Accepted: 10/16/2019] [Indexed: 01/15/2023]
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Modulation of the storage of social recognition memory by neurotransmitter systems in the insular cortex. Behav Brain Res 2017; 334:129-134. [DOI: 10.1016/j.bbr.2017.07.044] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 11/20/2022]
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Leiser SC, Li Y, Pehrson AL, Dale E, Smagin G, Sanchez C. Serotonergic Regulation of Prefrontal Cortical Circuitries Involved in Cognitive Processing: A Review of Individual 5-HT Receptor Mechanisms and Concerted Effects of 5-HT Receptors Exemplified by the Multimodal Antidepressant Vortioxetine. ACS Chem Neurosci 2015; 6:970-86. [PMID: 25746856 DOI: 10.1021/cn500340j] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It has been known for several decades that serotonergic neurotransmission is a key regulator of cognitive function, mood, and sleep. Yet with the relatively recent discoveries of novel serotonin (5-HT) receptor subtypes, as well as an expanding knowledge of their expression level in certain brain regions and localization on certain cell types, their involvement in cognitive processes is still emerging. Of particular interest are cognitive processes impacted in neuropsychiatric and neurodegenerative disorders. The prefrontal cortex (PFC) is critical to normal cognitive processes, including attention, impulsivity, planning, decision-making, working memory, and learning or recall of learned memories. Furthermore, serotonergic dysregulation within the PFC is implicated in many neuropsychiatric disorders associated with prominent symptoms of cognitive dysfunction. Thus, it is important to better understand the overall makeup of serotonergic receptors in the PFC and on which cell types these receptors mediate their actions. In this Review, we focus on 5-HT receptor expression patterns within the PFC and how they influence cognitive behavior and neurotransmission. We further discuss the net effects of vortioxetine, an antidepressant acting through multiple serotonergic targets given the recent findings that vortioxetine improves cognition by modulating multiple neurotransmitter systems.
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Affiliation(s)
| | - Yan Li
- Lundbeck Research USA, Paramus, New Jersey 07650, United States
| | - Alan L. Pehrson
- Lundbeck Research USA, Paramus, New Jersey 07650, United States
| | - Elena Dale
- Lundbeck Research USA, Paramus, New Jersey 07650, United States
| | - Gennady Smagin
- Lundbeck Research USA, Paramus, New Jersey 07650, United States
| | - Connie Sanchez
- Lundbeck Research USA, Paramus, New Jersey 07650, United States
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Celada P, Puig MV, Artigas F. Serotonin modulation of cortical neurons and networks. Front Integr Neurosci 2013; 7:25. [PMID: 23626526 PMCID: PMC3630391 DOI: 10.3389/fnint.2013.00025] [Citation(s) in RCA: 252] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 04/01/2013] [Indexed: 01/20/2023] Open
Abstract
The serotonergic pathways originating in the dorsal and median raphe nuclei (DR and MnR, respectively) are critically involved in cortical function. Serotonin (5-HT), acting on postsynaptic and presynaptic receptors, is involved in cognition, mood, impulse control and motor functions by (1) modulating the activity of different neuronal types, and (2) varying the release of other neurotransmitters, such as glutamate, GABA, acetylcholine and dopamine. Also, 5-HT seems to play an important role in cortical development. Of all cortical regions, the frontal lobe is the area most enriched in serotonergic axons and 5-HT receptors. 5-HT and selective receptor agonists modulate the excitability of cortical neurons and their discharge rate through the activation of several receptor subtypes, of which the 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT3 subtypes play a major role. Little is known, however, on the role of other excitatory receptors moderately expressed in cortical areas, such as 5-HT2C, 5-HT4, 5-HT6, and 5-HT7. In vitro and in vivo studies suggest that 5-HT1A and 5-HT2A receptors are key players and exert opposite effects on the activity of pyramidal neurons in the medial prefrontal cortex (mPFC). The activation of 5-HT1A receptors in mPFC hyperpolarizes pyramidal neurons whereas that of 5-HT2A receptors results in neuronal depolarization, reduction of the afterhyperpolarization and increase of excitatory postsynaptic currents (EPSCs) and of discharge rate. 5-HT can also stimulate excitatory (5-HT2A and 5-HT3) and inhibitory (5-HT1A) receptors in GABA interneurons to modulate synaptic GABA inputs onto pyramidal neurons. Likewise, the pharmacological manipulation of various 5-HT receptors alters oscillatory activity in PFC, suggesting that 5-HT is also involved in the control of cortical network activity. A better understanding of the actions of 5-HT in PFC may help to develop treatments for mood and cognitive disorders associated with an abnormal function of the frontal lobe.
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Affiliation(s)
- Pau Celada
- Department of Neurochemistry and Neuropharmacology, Institut d' Investigacions Biomèdiques de Barcelona (CSIC), IDIBAPS Barcelona, Spain ; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid, Spain
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Chen PJ, Liang KC, Lin HC, Hsieh CL, Su KP, Hung MC, Sheen LY. Gastrodia elata Bl. Attenuated Learning Deficits Induced by Forced-Swimming Stress in the Inhibitory Avoidance Task and Morris Water Maze. J Med Food 2011; 14:610-7. [DOI: 10.1089/jmf.2010.1209] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Pei-Ju Chen
- Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Keng-Chen Liang
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Hui-Chen Lin
- Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Ching-Liang Hsieh
- Department of Chinese Medicine, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan
| | - Kuan-Pin Su
- Department of Psychiatry, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan
| | - Mei-Chu Hung
- Department of Food and Beverage Management, Kang-Ning University, Tainan, Taiwan
| | - Lee-Yan Sheen
- Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan
- Center for Food and Biomolecules, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan
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Heo S, Patil SS, Jung G, Höger H, Lubec G. A serotonin receptor 1A containing complex in hippocampus of PWD/PhJ mice is linked to training effects in the Barnes maze. Behav Brain Res 2011; 216:389-95. [DOI: 10.1016/j.bbr.2010.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 08/09/2010] [Accepted: 08/16/2010] [Indexed: 11/16/2022]
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Domschke K, Stevens S, Pfleiderer B, Gerlach AL. Interoceptive sensitivity in anxiety and anxiety disorders: an overview and integration of neurobiological findings. Clin Psychol Rev 2009; 30:1-11. [PMID: 19751958 DOI: 10.1016/j.cpr.2009.08.008] [Citation(s) in RCA: 337] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 08/24/2009] [Accepted: 08/24/2009] [Indexed: 10/20/2022]
Abstract
Interoceptive sensitivity, particularly regarding heartbeat, has been suggested to play a pivotal role in the pathogenesis of anxiety and anxiety disorders. This review provides an overview of methods which are frequently used to assess heartbeat perception in clinical studies and summarizes presently available results referring to interoceptive sensitivity with respect to heartbeat in anxiety-related traits (anxiety sensitivity, state/trait anxiety), panic disorder and other anxiety disorders. In addition, recent neurobiological studies of neuronal activation correlates of heartbeat perception using positron emission tomography (PET), functional magnetic resonance imaging (fMRI) or electroencephalographic (EEG) techniques are presented. Finally, possible clinical and therapeutic implications (e.g., beta-blockers, biofeedback therapy, cognitive interventions and interoceptive exposure) of the effects of heartbeat perception on anxiety and the anxiety disorders and the potential use of interoceptive sensitivity as an intermediate phenotype of anxiety disorders in future neurobiological and genetic studies are discussed.
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Affiliation(s)
- Katharina Domschke
- Department of Psychiatry and Psychotherapy, University of Münster, Albert-Schweitzer-Strasse 11, D-48149 Münster, Germany.
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Mallet PE, Moore CA, Collie MT, Satvat E. Regional distribution of Ginkgo biloba-induced c-Fos immunoreactivity. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2009; 16:361-368. [PMID: 18757190 DOI: 10.1016/j.phymed.2008.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 06/25/2008] [Accepted: 07/07/2008] [Indexed: 05/26/2023]
Abstract
A growing literature supports the notion that Ginkgo biloba has cognitive enhancing and anxiolytic properties; however, its effects on neuronal populations have yet to be characterized. The present study used c-Fos immunoreactivity (Fos-IR) to characterize functional activity in selected brain regions following administration of a standardized Ginkgo biloba extract. Because Ginkgo is typically consumed orally, Exp 1 sought to identify patterns of neural activity induced by oral administration. To ensure that the alterations in functional neural activity observed in Exp 1 were not simply due to novel gustatory experience, Exp 2 characterized patterns of Fos-IR following intraperitoneal administration of Ginkgo. Rats were habituated to handling and experimental conditions. In Exp 1, rats self-administered 150 mg/kg Ginkgo or vehicle alone (strawberry jam) orally. In Exp 2, rats were injected with Ginkgo (2.5 or 25 mg/kg, i.p.) or vehicle (0.3% gum Arabic). Animals were anaesthetized and perfused transcardially. Brains were sectioned, immunostained using a c-Fos antibody, then the number of labelled cells was quantified microscopically in selected brain regions. In both experiments Ginkgo increased Fos-IR in numerous brain regions including the insular cortex and amygdala. Intraperitoneal administration induced Fos-IR in some additional regions including the nucleus accumbens and dentate gyrus. Results provide important preliminary data serving to identify several candidate neural sites involved in the cognitive enhancing and anxiolytic effects of Ginkgo biloba.
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Affiliation(s)
- P E Mallet
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada N2L 3C5.
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11
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Molodtsova GF. Serotonergic mechanisms of memory trace retrieval. Behav Brain Res 2008; 195:7-16. [DOI: 10.1016/j.bbr.2007.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 12/06/2007] [Accepted: 12/06/2007] [Indexed: 11/29/2022]
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12
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Chen HI, Lin LC, Yu L, Liu YF, Kuo YM, Huang AM, Chuang JI, Wu FS, Liao PC, Jen CJ. Treadmill exercise enhances passive avoidance learning in rats: The role of down-regulated serotonin system in the limbic system. Neurobiol Learn Mem 2008; 89:489-96. [PMID: 17892954 DOI: 10.1016/j.nlm.2007.08.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2007] [Revised: 08/03/2007] [Accepted: 08/08/2007] [Indexed: 11/25/2022]
Abstract
While serotonin (5-HT) may impair learning and memory, exercise has been reported to improve them. Whether chronic exercise can facilitate fear memory via regulating the serotonin system is unknown. We examined the effects of 4-week treadmill exercise training on levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA), the protein expression of its receptor 5-HT(1A) and transporter in the amygdala, hippocampus and prefrontal cortex of male Sprague-Dawley rats. Our results demonstrated that treadmill exercise (1) improved the passive avoidance learning performance; (2) decreased the 5-HT level in the hippocampus; (3) decreased the expression of 5-HT(1A) receptor in the amygdala without altering the transporter expression. Moreover, pretreatment with 0.1 mg/kg 8-hydroxy-di-n-propylamino tetralin, a selective 5-HT(1A) receptor agonist, impaired the passive avoidance performance and completely abolished the exercise-enhanced fear memory. Our results suggest that down-regulation of the 5-HT system in the limbic system, i.e., the reduction of the hippocampus 5-HT content and the amygdala 5-HT(1A) receptor expression, may be involved in the exercise-enhanced fear memory.
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Affiliation(s)
- Hsiun-Ing Chen
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
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Meneses A, Perez-Garcia G. 5-HT1A receptors and memory. Neurosci Biobehav Rev 2007; 31:705-27. [PMID: 17418894 DOI: 10.1016/j.neubiorev.2007.02.001] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Revised: 01/03/2007] [Accepted: 02/13/2007] [Indexed: 11/19/2022]
Abstract
The study of 5-hydroxytryptamine (5-HT) systems has benefited from the identification, classification and cloning of multiple 5-HT receptors (5-HT(1)-5-HT(7)). Increasing evidence suggests that 5-HT pathways, reuptake site/transporter complex and 5-HT receptors represent a strategic distribution for learning and memory. A key question still remaining is whether 5-HT markers (e.g., receptors) are directly or indirectly contributing to the physiological and pharmacological basis of memory and its pathogenesis or, rather, if they represent protective or adaptable mechanisms (at least in initial stages). In the current paper, the major aim is to revise recent advances regarding mammalian 5-HT(1A) receptors in light of their physiological, pathophysiological and therapeutic implications in memory. An attempt is made to identify and discuss sources of discrepancies by employing an analytic approach to examine the nature and degree of difficulty of behavioral tasks used, as well as implicating other factors (for example, brain areas, training time or duration, and drug administration) which might offer new insights into the understanding and interpretation of these data. In this context, 8-OH-DPAT deserves special attention since for many years it has been the more selective 5-HT drug and, hence, more frequently used. As 5-HT(1A) receptors are key components of serotonergic signaling, investigation of their memory mechanisms and action sites and the conditions under which they might operate, could yield valuable insights. Moreover, selective drugs with agonists, neutral antagonists or inverse agonist properties for 5-HT(1A) (and 5-HT(7)) receptors may constitute a new therapeutic opportunity for learning and memory disorders.
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Affiliation(s)
- Alfredo Meneses
- Department de Farmacobiologia, CINVESTAV-IPN, Tenorios 235, Granjas Coapa, México.
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Molodtsova GF. Metabolism and Receptor Binding of Serotonin in Brain Structures During Performance of a Conditioned Passive Avoidance Response. ACTA ACUST UNITED AC 2005; 35:685-92. [PMID: 16433063 DOI: 10.1007/s11055-005-0111-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The levels of serotonin and its metabolite 5-hydroxyindoleacetic acid, monoamine oxidase activity, and the specific binding of the radioligand [3H]serotonin were measured in the prefrontal cortex, striatum, amygdaloid complex, hippocampus, and periacqueductal gray matter of the midbrain in rats at different time points after training to a conditioned passive avoidance reaction. Changes in serotoninergic activity were found to be characteristic only for the process of reproducing the conditioned reaction. The metabolism and serotonin receptor binding in these brain structures did not change immediately after the training period or one day after this, or in conditions of failure to reproduce the reaction because of amnesia, or in untrained animals. The involvement of the brain serotoninergic system in the process of performing the conditioned reaction was found to demonstrate a spatial-structural selectivity: the metabolism and receptor binding of serotonin changed in the amygdaloid complex, periacqueductal gray matter, and the striatum, while no changes were seen in the hippocampus or prefrontal cortex. All three brain structures showed decreases in [3H]serotonin receptor binding of. Serotonin levels did not change, though the amygdaloid complex and periacqueductal gray matter showed increases in oxidative deamination of serotonin and increases in the active transport of the metabolite, while the striatum showed decreases in serotonin catabolism. The differences in the catabolism of this neurotransmitter suggest that the decrease in serotonin receptor binding in these brain structures depends on different synaptic processes--presynaptic in the striatum and postsynaptic in the amygdaloid complex and periacqueductal gray matter. It is concluded that the decrease in the functional activity of serotoninergic transmission in the amygdaloid complex and periacqueductal gray matter is one of the mechanisms involved in activation of the emotiogenic system triggering the process of reproduction of the memory trace.
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Affiliation(s)
- G F Molodtsova
- Laboratory for the Mechanisms of Memory Regulation, State Science Research Institute of Physiology, Siberian Division, Russian Academy of Medical Sciences, Novosibirsk.
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Abstract
The prevalence of dementia is growing in developed countries where elderly patients are increasing in numbers. Neurotransmission modulation is one approach to the treatment of dementia. Cholinergic precursors, anticholinesterases, nicotine receptor agonists and muscarinic M(2) receptor antagonists are agents that enhance cholinergic neurotransmission and that depend on having some intact cholinergic innervation to be effective in the treatment of dementia. The cholinergic precursor choline alfoscerate may be emerging as a potential useful drug in the treatment of dementia, with few adverse effects. Of the anticholinesterases, donepezil, in addition to having a similar efficacy to tacrine in mild-to-moderate Alzheimer's disease (AD), appears to have major advantages; its use is associated with lower drop-out rates in clinical trials, a lower incidence of cholinergic-like side effects and no liver toxicity. Rivastigmine is efficacious in the treatment in dementia with Lewy bodies, a condition in which the other anticholinesterases have not been tested extensively to date. Galantamine is an anticholinesterase and also acts as an allosteric potentiating modulator at nicotinic receptors to increase the release of acetylcholine. Pooled data from clinical trials of patients with mild-to-moderate AD suggest that the benefits and safety profile of galantamine are similar to those of the anticholinesterases. Selective nicotine receptor agonists are being developed that enhance cognitive performance without influencing autonomic and skeletal muscle function, but these have not yet entered clinical trial for dementia. Unlike the cholinergic enhancers, the M(1) receptor agonists do not depend upon intact cholinergic nerves but on intact M(1) receptors for their action, which are mainly preserved in AD and dementia with Lewy bodies. The M(1) receptor-selective agonists developed to date have shown limited efficacy in clinical trials and have a high incidence of side effects. A major recent advancement in the treatment of dementia is memantine, a non-competitive antagonist at NMDA receptors. Memantine is beneficial in the treatment of severe and moderate-to-severe AD and may also be of some benefit in the treatment of mild-to-moderate vascular dementia. Drugs that modulate 5-HT, somatostatin and noradrenergic neurotransmission are also being considered for the treatment of dementia.
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Affiliation(s)
- Sheila A Doggrell
- School of Biomedical Sciences, the University of Queensland, QLD 4072, Australia
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Fedotova JO, Hartmann G, Lénárd L, Sapronov NS. Involvement of 5-HT1?receptors in passive avoidance learning in intact and ovariectomized female rats. ACTA ACUST UNITED AC 2004; 91:185-96. [PMID: 16438112 DOI: 10.1556/aphysiol.91.2004.3-4.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The influence of chronic administration of 5-HT1A receptor agonist 8-OH-DPAT (0.05 mg/kg, s.c.) and 5-HT1A receptor antagonist NAN-190 (0.1 mg/kg, i.p.) injected for 14 days alone or in combination with 17beta-estradiol (0.5 microg i.m./rat/day) was studied on passive avoidance performance (PAR) and on behavior in the open field test in adult intact and ovariectomized (OVX) female rats. Administration of 5-HT1A receptor antagonist NAN-190 alone significantly improved PAR (p<0.05) in intact females with proestrus and estrus and in OVX females. Administration of 5-HT1A receptor agonist 8-OH-DPAT alone or in combination with 17beta-estradiol significantly (p<0.05) improved PAR in OVX rats and failed to normalize PAR in intact rats with proestrus and estrus. Results of the work specify the involvement of 5-HT1A receptors in the mechanisms of passive avoidance learning in OVX female rats.
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Affiliation(s)
- Julia O Fedotova
- SV Anichkov Department of Neuropharmacology, Institute of Experimental Medicine of the Russian Academy of Medical Sciences, St Petersburg, Russia.
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Miranda MI, McGaugh JL. Enhancement of inhibitory avoidance and conditioned taste aversion memory with insular cortex infusions of 8-Br-cAMP: involvement of the basolateral amygdala. Learn Mem 2004; 11:312-7. [PMID: 15169861 PMCID: PMC419734 DOI: 10.1101/lm.72804] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 02/11/2004] [Indexed: 11/25/2022]
Abstract
There is considerable evidence that in rats, the insular cortex (IC) and amygdala are involved in the learning and memory of aversively motivated tasks. The present experiments examined the effects of 8-Br-cAMP, an analog of cAMP, and oxotremorine, a muscarinic agonist, infused into the IC after inhibitory avoidance (IA) training and during the acquisition/consolidation of conditioned taste aversion (CTA). Posttraining infusion into the IC of 0.3 microg oxotremorine and 1.25 microg 8-Br-cAMP enhanced IA retention. Infusions of 8-Br-cAMP, but not oxotremorine, into the IC enhanced taste aversion. The experiments also examined whether noradrenergic activity in the basolateral amygdala (BLA) is critical in enabling the enhancement of CTA and IA memory induced by drug infusions administered into the IC. For both CTA and IA, ipsilateral infusions of beta-adrenergic antagonist propranolol administered into the BLA blocked the retention-enhancing effect of 8-Br-cAMP or oxotremorine infused into the IC. These results indicate that the IC is involved in the consolidation of memory for both IA and CTA, and this effect requires intact noradrenergic activity into the BLA. These findings provide additional evidence that the BLA interacts with other brain regions, including sensory cortex, in modulating memory consolidation.
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Affiliation(s)
- María I Miranda
- Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, California 92697-3800, USA.
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