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Hamidi N, Nozad A, Sheikhkanloui Milan H, Amani M. Okadaic acid attenuates short-term and long-term synaptic plasticity of hippocampal dentate gyrus neurons in rats. Neurobiol Learn Mem 2019; 158:24-31. [PMID: 30630043 DOI: 10.1016/j.nlm.2019.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/13/2018] [Accepted: 01/05/2019] [Indexed: 01/04/2023]
Abstract
Protein phosphorylation states have a pivotal role in regulation of synaptic plasticity and long-term modulation of synaptic transmission. Serine/threonine protein phosphatase 1 (PP1) and 2A (PP2A) have a critical effect on various regulatory mechanisms involved in synaptic plasticity, learning and memory. Okadaic acid (OKA), a potent inhibitor of PP1 and PP2A, reportedly leads to cognitive decline and Alzheimer's disease (AD)-like pathology. The aim of this study was to examine the effect of OKA on electrophysiological characteristics of hippocampal dentate gyrus (DG) neurons in vivo. Male Wistar rats were divided into two control and OKA groups. OKA was injected intracerebroventricularly (i.c.v.) into lateral ventricles and after two weeks the long-term potentiation (LTP) and paired-pulse responses recorded from hippocampal perforant path-DG synapses in order to assess short-term and long-term synaptic plasticity. Results of this study revealed that OKA-induced inhibition of PP1 and PP2A activity drastically attenuates the field excitatory postsynaptic potential (fEPSP) slope and population spike (PS) amplitude following paired pulse and high frequency stimulation (HFS) of hippocampal DG neurons indicating pre- and post-synaptic involvement in electrical activity of these neurons. Administration of OKA impaired the short-term and long-term spatial memories conducted by Y-maze and passive avoidance tests, respectively. OKA-induced attenuation in electrophysiological activity and consequent memory deficits also provide a beneficial tool for studying neurodegenerative disorders such as AD.
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Affiliation(s)
- Nasrin Hamidi
- Department of Physiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
| | - Abdollah Nozad
- Department of Physiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
| | | | - Mohammad Amani
- Department of Physiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran; Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA.
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Rahman A, Rao MS, Khan KM. Intraventricular infusion of quinolinic acid impairs spatial learning and memory in young rats: a novel mechanism of lead-induced neurotoxicity. J Neuroinflammation 2018; 15:263. [PMID: 30217162 PMCID: PMC6137743 DOI: 10.1186/s12974-018-1306-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/04/2018] [Indexed: 12/20/2022] Open
Abstract
Background Lead (Pb), a heavy metal, and quinolinic acid (QA), a metabolite of the kynurenine pathway of tryptophan metabolism, are known neurotoxicants. Both Pb and QA impair spatial learning and memory. Pb activates astrocytes and microglia, which in turn induce the synthesis of QA. We hypothesized increased QA production in response to Pb exposure as a novel mechanism of Pb-neurotoxicity. Methods Two experimental paradigms were used. In experiment one, Wistar rat pups were exposed to Pb via their dams’ drinking water from postnatal day 1 to 21. Control group was given regular water. In the second protocol, QA (9 mM) or normal saline (as Vehicle Control) was infused into right lateral ventricle of 21-day old rats for 7 days using osmotic pumps. Learning and memory were assessed by Morris water maze test on postnatal day 30 or 45 in both Pb- and QA-exposed rats. QA levels in the Pb exposed rats were measured in blood by ELISA and in the brain by immunohistochemistry on postnatal days 45 and 60. Expression of various molecules involved in learning and memory was analyzed by Western blot. Means of control and experimental groups were compared with two-way repeated measure ANOVA (learning) and t test (all other variables). Results Pb exposure increased QA level in the blood (by ~ 58%) and increased (p < 0.05) the number of QA-immunoreactive cells in the cortex, and CA1, CA3 and dentate gyrus regions of the hippocampus, compared to control rats. In separate experiments, QA infusion impaired learning and short-term memory similar to Pb. PSD-95, PP1, and PP2A were decreased (p < 0.05) in the QA-infused rats, whereas tau phosphorylation was increased, compared to vehicle infused rats. Conclusion Putting together the results of the two experimental paradigms, we propose that increased QA production in response to Pb exposure is a novel mechanism of Pb-induced neurotoxicity.
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Affiliation(s)
- Abdur Rahman
- Department of Food Science and Nutrition, College of Life Sciences, Kuwait University, Kuwait City, Kuwait.
| | - Muddanna S Rao
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Khalid M Khan
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
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Mukilan M, Bogdanowicz W, Marimuthu G, Rajan KE. Odour discrimination learning in the Indian greater short-nosed fruit bat ( Cynopterus sphinx): differential expression of Egr-1, C-fos and PP-1 in the olfactory bulb, amygdala and hippocampus. ACTA ACUST UNITED AC 2018; 221:jeb.175364. [PMID: 29674380 DOI: 10.1242/jeb.175364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 04/16/2018] [Indexed: 01/05/2023]
Abstract
Activity-dependent expression of immediate-early genes (IEGs) is induced by exposure to odour. The present study was designed to investigate whether there is differential expression of IEGs (Egr-1, C-fos) in the brain region mediating olfactory memory in the Indian greater short-nosed fruit bat, Cynopterus sphinx We assumed that differential expression of IEGs in different brain regions may orchestrate a preference odour (PO) and aversive odour (AO) memory in C. sphinx We used preferred (0.8% w/w cinnamon powder) and aversive (0.4% w/v citral) odour substances, with freshly prepared chopped apple, to assess the behavioural response and induction of IEGs in the olfactory bulb, hippocampus and amygdala. After experiencing PO and AO, the bats initially responded to both, later only engaging in feeding bouts in response to the PO food. The expression pattern of EGR-1 and c-Fos in the olfactory bulb, hippocampus and amygdala was similar at different time points (15, 30 and 60 min) following the response to PO, but was different for AO. The response to AO elevated the level of c-Fos expression within 30 min and reduced it at 60 min in both the olfactory bulb and the hippocampus, as opposed to the continuous increase noted in the amygdala. In addition, we tested whether an epigenetic mechanism involving protein phosphatase-1 (PP-1) acts on IEG expression. The observed PP-1 expression and the level of unmethylated/methylated promoter revealed that C-fos expression is possibly controlled by odour-mediated regulation of PP-1. These results in turn imply that the differential expression of C-fos in the hippocampus and amygdala may contribute to olfactory learning and memory in C. sphinx.
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Affiliation(s)
- Murugan Mukilan
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, India
| | - Wieslaw Bogdanowicz
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00-679 Warszawa, Poland
| | - Ganapathy Marimuthu
- Department of Animal Behavior and Physiology, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, India
| | - Koilmani Emmanuvel Rajan
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, India
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Cheng XY, He S, Liang XF, Song Y, Yuan XC, Li L, Wen ZY, Cai WJ, Tao YX. Molecular cloning, expression and single nucleotide polymorphisms of protein phosphatase 1 (PP1) in mandarin fish ( Siniperca chuatsi ). Comp Biochem Physiol B Biochem Mol Biol 2015; 189:69-79. [DOI: 10.1016/j.cbpb.2015.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 07/28/2015] [Accepted: 08/04/2015] [Indexed: 01/27/2023]
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Molecular and Functional Characterization of Bacopa monniera: A Retrospective Review. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:945217. [PMID: 26413131 PMCID: PMC4564644 DOI: 10.1155/2015/945217] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 03/24/2015] [Accepted: 04/09/2015] [Indexed: 12/21/2022]
Abstract
Over the last 50 years, laboratories around the world analyzed the pharmacological effect of Bacopa monniera extract in different dimensions, especially as a nerve tonic and memory enhancer. Studies in animal model evidenced that Bacopa treatment can attenuate dementia and enhances memory. Further, they demonstrate that Bacopa primarily either acts via antioxidant mechanism (i.e., neuroprotection) or alters different neurotransmitters (serotonin (5-hydroxytryptamine, 5-HT), dopamine (DA), acetylcholine (ACh), γ-aminobutyric acid (GABA)) to execute the pharmacological effect. Among them, 5-HT has been shown to fine tune the neural plasticity, which is a substrate for memory formation. This review focuses on the studies which trace the effect of Bacopa treatment on serotonergic system and 5-HT mediated key molecular changes that are associated with memory formation.
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Zhang JJ, Han J, Sui N. Okadaic acid blocks the effects of 5-aza-2-deoxycytidine on consolidation, acquisition and retrieval of morphine-induced place preference in rats. Neuropharmacology 2014; 86:282-93. [DOI: 10.1016/j.neuropharm.2014.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 07/18/2014] [Accepted: 08/05/2014] [Indexed: 12/22/2022]
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Cavallo JS, Hamilton BN, Farley J. In vitro extinction learning in Hermissenda: involvement of conditioned inhibition molecules. Front Behav Neurosci 2014; 8:354. [PMID: 25374517 PMCID: PMC4204529 DOI: 10.3389/fnbeh.2014.00354] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 09/23/2014] [Indexed: 11/30/2022] Open
Abstract
Extinction of a conditioned association is typically viewed as the establishment of new learning rather than the erasure of the original memory. However, recent research in the nudibranch, Hermissenda crassicornis (H.c.) demonstrated that extinction training (using repeated light-alone presentations) given 15 min, but not 23 h, after memory acquisition reversed both the cellular correlates of learning (enhanced Type B cell excitability) and the behavioral changes (reduced phototaxis) produced by associative conditioning (pairings of light, CS, and rotation, US). Here, we investigated the putative molecular signaling pathways that underlie this extinction in H.c. by using a novel in vitro protocol combined with pharmacological manipulations. After intact H.c. received either light-rotation pairings (Paired), random presentations of light and rotation (Random), or no stimulation (Untrained), B cells from isolated CNSs were recorded from during exposure to extinction training consisting of two series of 15 consecutive light-steps (LSs). When in vitro extinction was administered shortly (2 h, but not 24 h) after paired training, B cells from Paired animals showed progressive and robust declines in spike frequency by the 30th LS, while control cells (Random and Untrained) did not. We found that several molecules implicated in H.c. conditioned inhibitory (CI) learning, protein phosphatase 1 (PP1) and arachidonic acid (AA)/12-lipoxygenase (12-LOX) metabolites, also contributed to the spike frequency decreases produced by in vitro extinction. Protein phosphatase 2B (PP2B) also appeared to play a role. Calyculin A (PP1 inhibitor), cyclosporin A (PP2B inhibitor), and baicalein (a 12-LOX inhibitor) all blocked the spike frequency declines in Paired B cells produced by 30 LSs. Conversely, injection of catalytically-active PP1 (caPP1) or PP2B (caPP2B) into Untrained B cells partially mimicked the spike frequency declines observed in Paired cells, as did bath-applied AA, and occluded additional LS-produced reductions in spiking in Paired cells.
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Affiliation(s)
- Joel S Cavallo
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University Bloomington, IN, USA
| | - Brittany N Hamilton
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University Bloomington, IN, USA
| | - Joseph Farley
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University Bloomington, IN, USA
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Mirante O, Brandalise F, Bohacek J, Mansuy IM. Distinct molecular components for thalamic- and cortical-dependent plasticity in the lateral amygdala. Front Mol Neurosci 2014; 7:62. [PMID: 25071439 PMCID: PMC4080466 DOI: 10.3389/fnmol.2014.00062] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 06/16/2014] [Indexed: 01/05/2023] Open
Abstract
N-methyl-D-aspartate receptor (NMDAR)-dependent long-term depression (LTD) in the lateral nucleus of the amygdala (LA) is a form of synaptic plasticity thought to be a cellular substrate for the extinction of fear memory. The LA receives converging inputs from the sensory thalamus and neocortex that are weakened following fear extinction. Combining field and patch-clamp electrophysiological recordings in mice, we show that paired-pulse low-frequency stimulation can induce a robust LTD at thalamic and cortical inputs to LA, and we identify different underlying molecular components at these pathways. We show that while LTD depends on NMDARs and activation of the protein phosphatases PP2B and PP1 at both pathways, it requires NR2B-containing NMDARs at the thalamic pathway, but NR2C/D-containing NMDARs at the cortical pathway. LTD appears to be induced post-synaptically at the thalamic input but presynaptically at the cortical input, since post-synaptic calcium chelation and NMDAR blockade prevent thalamic but not cortical LTD. These results highlight distinct molecular features of LTD in LA that may be relevant for traumatic memory and its erasure, and for pathologies such as post-traumatic stress disorder (PTSD).
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Affiliation(s)
- Osvaldo Mirante
- Brain Research Institute, Medical Faculty, University Zürich Zürich, Switzerland ; Department of Health Science and Technology, Swiss Federal Institute of Technology Zürich, Switzerland
| | - Federico Brandalise
- Brain Research Institute, Medical Faculty, University Zürich Zürich, Switzerland
| | - Johannes Bohacek
- Brain Research Institute, Medical Faculty, University Zürich Zürich, Switzerland ; Department of Health Science and Technology, Swiss Federal Institute of Technology Zürich, Switzerland
| | - Isabelle M Mansuy
- Brain Research Institute, Medical Faculty, University Zürich Zürich, Switzerland ; Department of Health Science and Technology, Swiss Federal Institute of Technology Zürich, Switzerland
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Preethi J, Singh HK, Venkataraman JS, Rajan KE. Standardised extract of Bacopa monniera (CDRI-08) improves contextual fear memory by differentially regulating the activity of histone acetylation and protein phosphatases (PP1α, PP2A) in hippocampus. Cell Mol Neurobiol 2014; 34:577-89. [PMID: 24610280 DOI: 10.1007/s10571-014-0042-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 02/22/2014] [Indexed: 01/24/2023]
Abstract
Contextual fear conditioning is a paradigm for investigating cellular mechanisms involved in hippocampus-dependent memory. Earlier, we showed that standardised extract of Bacopa monniera (CDRI-08) improves hippocampus-dependent learning in postnatal rats by elevating the level of serotonin (5-hydroxytryptamine, 5-HT), activate 5-HT3A receptors, and cyclic adenosine monophosphate (cAMP) response element binding (CREB) protein. In this study, we have further examined the molecular mechanism of CDRI-08 in hippocampus-dependent memory and compared to the histone deacetylase (HDACs) inhibitor sodium butyrate (NaB). To assess the hippocampus-dependent memory, wistar rat pups were subjected to contextual fear conditioning (CFC) following daily (postnatal days 15-29) administration of vehicle solution (0.5 % gum acacia + 0.9 % saline)/CDRI-08 (80 mg/kg, p.o.)/NaB (1.2 g/kg in PBS, i.p.). CDRI-08/NaB treated group showed enhanced freezing behavior compared to control group when re-exposed to the same context. Administration of CDRI-08/NaB resulted in activation of extracellular signal-regulated kinase ERK/CREB signaling cascade and up-regulation of p300, Ac-H3 and Ac-H4 levels, and down-regulation of HDACs (1, 2) and protein phosphatases (PP1α, PP2A) in hippocampus following CFC. This would subsequently result in an increased brain-derived neurotrophic factor (Bdnf) (exon IV) mRNA in hippocampus. Altogether, our results indicate that CDRI-08 enhances hippocampus-dependent contextual memory by differentially regulating histone acetylation and protein phosphatases in hippocampus.
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Affiliation(s)
- Jayakumar Preethi
- Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620024, India
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Adaikkan C, Rosenblum K. The role of protein phosphorylation in the gustatory cortex and amygdala during taste learning. Exp Neurobiol 2012; 21:37-51. [PMID: 22792024 PMCID: PMC3381211 DOI: 10.5607/en.2012.21.2.37] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 02/17/2012] [Indexed: 01/22/2023] Open
Abstract
Protein phosphorylation and dephosphorylation form a major post-translation mechanism that enables a given cell to respond to ever-changing internal and external environments. Neurons, similarly to any other cells, use protein phosphorylation/dephosphorylation to maintain an internal homeostasis, but they also use it for updating the state of synaptic and intrinsic properties, following activation by neurotransmitters and growth factors. In the present review we focus on the roles of several families of kinases, phosphatases, and other synaptic-plasticity-related proteins, which activate membrane receptors and various intracellular signals to promote transcription, translation and protein degradation, and to regulate the appropriate cellular proteomes required for taste memory acquisition, consolidation and maintenance. Attention is especially focused on the protein phosphorylation state in two forebrain areas that are necessary for taste-memory learning and retrieval: the insular cortex and the amygdala. The various temporal phases of taste learning require the activation of appropriate waves of biochemical signals. These include: extracellular signal regulated kinase I and II (ERKI/II) signal transduction pathways; Ca(2+)-dependent pathways; tyrosine kinase/phosphatase-dependent pathways; brain-derived neurotrophicfactor (BDNF)-dependent pathways; cAMP-responsive element bindingprotein (CREB); and translation-regulation factors, such as initiation and elongation factors, and the mammalian target of rapamycin (mTOR). Interestingly, coding of hedonic and aversive taste information in the forebrain requires activation of different signal transduction pathways.
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Rahman A, Khan KM, Al-Khaledi G, Khan I, Al-Shemary T. Over activation of hippocampal serine/threonine protein phosphatases PP1 and PP2A is involved in lead-induced deficits in learning and memory in young rats. Neurotoxicology 2012; 33:370-83. [DOI: 10.1016/j.neuro.2012.02.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 02/15/2012] [Accepted: 02/21/2012] [Indexed: 11/27/2022]
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Panguluri SK, Kuwabara N, Kang Y, Cooper N, Lundy RF. Conditioned taste aversion dependent regulation of amygdala gene expression. Physiol Behav 2012; 105:996-1006. [PMID: 22119580 PMCID: PMC3260345 DOI: 10.1016/j.physbeh.2011.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 01/05/2023]
Abstract
The present experiments investigated gene expression in the amygdala following contingent taste/LiCl treatment that supports development of conditioned taste aversion (CTA). The use of whole genome chips and stringent data set filtering led to the identification of 168 genes regulated by CTA compared to non-contingent LiCl treatment that does not support CTA learning. Seventy-six of these genes were eligible for network analysis. Such analysis identified "behavior" as the top biological function, which was represented by 15 of the 76 genes. These genes included several neuropeptides, G protein-coupled receptors, ion channels, kinases, and phosphatases. Subsequent qRT-PCR analyses confirmed changes in mRNA expression for 5 of 7 selected genes. We were able to demonstrate directionally consistent changes in protein level for 3 of these genes; insulin 1, oxytocin, and major histocompatibility complex class I-C. Behavioral analyses demonstrated that blockade of central insulin receptors produced a weaker CTA that was less resistant to extinction. Together, these results support the notion that we have identified downstream genes in the amygdala that contribute to CTA learning.
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Affiliation(s)
- Siva K. Panguluri
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville KY
| | - Nobuyuki Kuwabara
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville KY
| | - Yi Kang
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis MO
| | - Nigel Cooper
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville KY
| | - Robert F. Lundy
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville KY
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Kwon B, Houpt TA. Mitogen-activated protein kinase in the amygdala plays a critical role in lithium chloride-induced taste aversion learning. Neurobiol Learn Mem 2012; 97:132-9. [PMID: 22085719 PMCID: PMC3532514 DOI: 10.1016/j.nlm.2011.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 10/20/2011] [Accepted: 10/31/2011] [Indexed: 11/28/2022]
Abstract
The intracellular mitogen-activated protein kinase (MAPK) pathway in the brain is necessary for the formation of a variety of memories including conditioned taste aversion (CTA) learning. However, the functional role of MAPK activation in the amygdala during lithium chloride (LiCl)-induced CTA learning has not been established. In the present study, we investigated if local microinjection of SL327, a MAPK kinase inhibitor, into the rat amygdala could alleviate LiCl-induced CTA learning. Our results revealed that acute administration of a high dose of LiCl (0.15M, 12 ml/kg, i.p.) rapidly increased the level of phosphorylated MAPK (pMAPK)-positive cells in the central nucleus of the amygdala (CeA) and nucleus of the solitary tract (NTS) of rats as measured by immunohistochemistry. Local microinjection of SL327 (1 μg/0.5 μl/hemisphere) into the CeA 10 min before LiCl administration decreased both the strength of LiCl-induced CTA paired with 0.125% saccharin and the level of LiCl-induced pMAPK-positive cells in the CeA, but not in the NTS. Our data suggest that the intracellular signaling cascade of the MAPK pathway in the CeA plays a critical role in the processing of visceral information induced by LiCl for CTA learning.
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Affiliation(s)
- Bumsup Kwon
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, FL 32306-4295, USA
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Dossat AM, Lilly N, Kay K, Williams DL. Glucagon-like peptide 1 receptors in nucleus accumbens affect food intake. J Neurosci 2011; 31:14453-7. [PMID: 21994361 PMCID: PMC3328130 DOI: 10.1523/jneurosci.3262-11.2011] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/09/2011] [Accepted: 08/15/2011] [Indexed: 12/15/2022] Open
Abstract
Central glucagon-like peptide 1 receptor (GLP-1R) stimulation suppresses food intake, and hindbrain GLP-1 neurons project to numerous feeding-relevant brain regions. One such region is the nucleus accumbens (NAc), which plays a role in reward and motivated behavior. Using immunohistochemical and retrograde tracing techniques in rats, we identified a robust projection from GLP-1 neurons in the nucleus of the solitary tract to the NAc. We hypothesized that activation of NAc GLP-1Rs suppresses feeding. When injected into the NAc core of rats at doses subthreshold for effect when administered to the lateral ventricle, GLP-1 significantly reduced food intake relative to vehicle at 1, 2, and 24 h posttreatment. The same doses had no effect when injected into the NAc shell. NAc core treatment with ventricle-subthreshold doses of the GLP-1R antagonist exendin (9-39) caused significant hyperphagia at 2 h posttreatment, suggesting that endogenous stimulation of NAc core GLP-1Rs plays a role in limiting food intake. It has been suggested that GLP-1 can cause nausea, but we found that NAc core administration of GLP-1 did not cause a conditioned taste aversion to saccharin, suggesting that the anorexic effect of NAc core GLP-1 is not caused by malaise. Finally, we observed that NAc core injection of GLP-1 significantly increased c-Fos expression in the NAc core. We conclude that that GLP-1Rs in the NAc play a physiologic role in food intake control, and suggest that the GLP-1 projection to NAc core may link satiation signal processing in the hindbrain with forebrain processing of food reward.
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Affiliation(s)
- Amanda M. Dossat
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | - Nicole Lilly
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | - Kristen Kay
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | - Diana L. Williams
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
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Manfrin C, Dreos R, Battistella S, Beran A, Gerdol M, Varotto L, Lanfranchi G, Venier P, Pallavicini A. Mediterranean mussel gene expression profile induced by okadaic acid exposure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:8276-8283. [PMID: 20879708 DOI: 10.1021/es102213f] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Seasonal seawater temperature increases define optimal growth conditions for Dinoflagellate species which can reach high concentrations in water column and also in filter-feeding organisms like Mytilus galloprovincialis. Commonly produced by Dinophysis and Prorocentrum spp., okadaic acid (OA) and its analogues are responsible for the Diarrheic Shellfish Poisoning (DSP) syndrome in humans. Closure of shellfishing grounds is therefore recommended by the EU when DSP toxin levels in shellfish exceed 16 μg OA 100 g(-1) flesh. Despite not being responsible for casualties either in humans or mussels, DSP outbreaks are considered natural events causing health and economic issues due to the frequency of their occurrence. Since gene expression studies offer a wide range of different solutions, we used a mussel cDNA microarray to evaluate gene expression changes in the digestive gland of mussels fed for five weeks with OA-contaminated nutrient. Among the differentially expressed genes we observed a general up-regulation of transcripts coding for stress proteins, proteins involved in cellular synthesis, and a few not annotated proteins. Overall, at the first time point analyzed we identified 58 candidate transcripts for OA-induced stress in mussels, half of which have unknown function. In this paper we present the first gene expression analysis performed on Mediterranean mussels exposed to okadaic acid. The characterization of these transcripts could be useful for the identification of an early physiological response to OA exposure.
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Affiliation(s)
- Chiara Manfrin
- Department of Life Sciences, Università di Trieste, P.le Valmaura, 9, Trieste, Italy
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