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Gihm SH, Kim BG, Kim S, Seo J, Park SY, Park CR. Characterization of self-assembled structure of discotic liquid crystal molecules using small-angle X-ray scattering and computer simulation methods based on intermolecular interactions. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Han MS, Lee YK, Kim WN, Lee HS, Joo JS, Park M, Lee HJ, Park CR. Effect of multi-walled carbon nanotube dispersion on the electrical, morphological and rheological properties of polycarbonate/multi-walled carbon nanotube composites. Macromol Res 2009. [DOI: 10.1007/bf03218627] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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53
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Kim SW, Cho HG, Park CR. Fabrication of unagglomerated polypyrrole nanospheres with controlled sizes from a surfactant-free emulsion system. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:9030-9036. [PMID: 19719218 DOI: 10.1021/la9007872] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We developed a very simple, template-free, and environmentally friendly one-step chemical synthesis route to fabricate unagglomerated polypyrrole (PPy) nanospheres. The proposed new fabrication method enables the production of size-controlled unagglomerated PPy nanospheres without the help of any supporting materials such as "hard" and "soft" templates and under mild conditions, viz., room temperature, atmospheric pressure, and no need for acid. From the theoretical calculation, we could find that our novel system was suitable to prepare the unagglomerated PPy spheres. The process is discussed on the basis the classical colloidal and microemulsion theory.
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An BK, Gihm SH, Chung JW, Park CR, Kwon SK, Park SY. Color-Tuned Highly Fluorescent Organic Nanowires/Nanofabrics: Easy Massive Fabrication and Molecular Structural Origin. J Am Chem Soc 2009; 131:3950-7. [DOI: 10.1021/ja806162h] [Citation(s) in RCA: 222] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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55
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Yang SJ, Park CR. Facile preparation of monodisperse ZnO quantum dots with high quality photoluminescence characteristics. NANOTECHNOLOGY 2008; 19:035609. [PMID: 21817583 DOI: 10.1088/0957-4484/19/03/035609] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report a new method that enables the facile synthesis of monodisperse zinc oxide (ZnO) quantum dots (QDs) with high quality photoluminescence (PL) characteristics. In the proposed method, ZnO QDs are grown on acid-treated multiwalled carbon nanotubes (a-MWCNTs) under remarkably mild reaction conditions (low temperature, short time, atmospheric pressure, and no need for subsequent thermal annealing). The ZnO QDs grown on the a-MWCNTs were monodisperse and highly crystalline, and had diameters of about 7 nm. Moreover, the a-MWCNT-grown ZnO QDs exhibited a definitive blue emission without defect-related blue-green emission, features that are indicative of definite quantum confinement effects and high quality.
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Jeong K, Lee W, Cha J, Park CR, Cho YW, Kwon IC. Regioselective succinylation and gelation behavior of glycol chitosan. Macromol Res 2008. [DOI: 10.1007/bf03218961] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Seo J, Kim S, Gihm SH, Park CR, Park SY. Highly fluorescent columnar liquid crystals with elliptical molecular shape: oblique molecular stacking and excited-state intramolecular proton-transfer fluorescence. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b711883j] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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58
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Cha J, Lee WB, Park CR, Cho YW, Ahn CH, Kwon IC. Preparation and characterization of cisplatin-incorporated chitosan hydrogels, microparticles, and nanoparticles. Macromol Res 2006. [DOI: 10.1007/bf03218726] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Nelson N, Palmes ED, Park CR, Weymouth PP, Bean WB. THE ABSORPTION, EXCRETION, AND PHYSIOLOGICAL EFFECT OF IODINE IN NORMAL HUMAN SUBJECTS. J Clin Invest 2006; 26:301-10. [PMID: 16695418 PMCID: PMC435670 DOI: 10.1172/jci101809] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Mu Jo S, Yeon Song M, Rack Ahn Y, Rae Park C, Young Kim D. Nanofibril Formation of Electrospun TiO2Fibers and its Application to Dye‐Sensitized Solar Cells. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2005. [DOI: 10.1080/10601320500229103] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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61
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Lee SJ, Park CR, Chang JY. Molecular aggregation of disklike benzenetricarboxamides containing diacetylenic groups in bulk and organic solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:9513-9519. [PMID: 15491180 DOI: 10.1021/la0493417] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We prepared disklike tris(4-alkylbutadiynylphenyl)-1,3,5-benzenetricarboxamide and tris[4-(4-alkyloxyphenyl)butadiynylphenyl]-1,3,5-benzenetricarboxamide, where three phenyl diacetylenic and diphenyl diacetylenic groups are connected to a benzene ring through amide linkages, respectively. The structures of self-assembled substances were investigated by using transmission electron microscopy, scanning electron microscopy, and X-ray diffraction techniques. All the compounds were highly viscous in melt states, and only compound 9 having three phenyl diacetylenic groups and hexyl tails showed a thermotropic mesophase on cooling. The compound with three diphenyl diacetylenic groups and dodecyloxy tails (13) formed a stable gel in THF/cyclohexane. The IR and X-ray analyses showed that in the gel state molecules were assembled into a rectangular columnar lattice and held each other by hydrogen bondings between amide groups. The compound with tetradecyloxy tails (14) formed stable colloidal particles in cyclohexane. The UV irradiation of 13 in a gel and 14 in a colloidal particle did not result in a long conjugated polymer because of the inappropriate alignment of diacetylenic groups for the topochemical polymerization.
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Kim YJ, Kim MI, Yun CH, Chang JY, Park CR, Inagaki M. Comparative study of carbon dioxide and nitrogen atmospheric effects on the chemical structure changes during pyrolysis of phenol–formaldehyde spheres. J Colloid Interface Sci 2004; 274:555-62. [PMID: 15144830 DOI: 10.1016/j.jcis.2003.12.029] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Accepted: 12/12/2003] [Indexed: 11/29/2022]
Abstract
The effect of CO(2) atmosphere on the chemical structure changes of resol-type phenol-formaldehyde spheres during pyrolysis was investigated, in comparison with that of N(2) atmosphere, using FT-IR, TGA, and elemental analysis techniques. It was found that, in contrast to the expectation that CO(2) may act as an oxidizing agent at high temperature, it behaves very similar to N(2) during pyrolysis of PF spheres up to 700 degree C, but results in a somewhat different extent of some specific reactions. That is, although the reactions occurring up to 700 degree C were dominated by crosslinking and/or polyaromatization under both CO(2) and N(2) atmospheres, fewer alkyl-phenolic ether bonds were formed under CO(2) than under N(2). As a consequence, the samples carbonized under CO(2) at 700 degree C were found to have more pendant groups on the edge carbon atoms of carbon in the carbonized samples than those prepared under N(2) atmosphere.
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Son YJ, Jang JS, Cho YW, Chung H, Park RW, Kwon IC, Kim IS, Park JY, Seo SB, Park CR, Jeong SY. Biodistribution and anti-tumor efficacy of doxorubicin loaded glycol-chitosan nanoaggregates by EPR effect. J Control Release 2003; 91:135-45. [PMID: 12932645 DOI: 10.1016/s0168-3659(03)00231-1] [Citation(s) in RCA: 229] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
An in vivo tumor targeting test of glycol-chitosan nanoaggregates was carried out with FITC-conjugated glycol-chitosan nanoaggregates (FTC-GC) and the doxorubicin conjugated glycol-chitosan (GC-DOX). To investigate its biodistribution in tumor-bearing rats, glycol-chitosan was labeled with fluorescein isothiocyanate (FITC), which formed nanoaggregates with a diameter of about 250 nm in aqueous media. GC-DOX nanoaggregates containing acid-sensitive spacers were prepared. The GC-DOX formed micelle-like nanoaggregates spontaneously in aqueous media. GC-DOX nanoaggregates had a narrow and unimodal size distribution, and its hydrodynamic diameter measured by dynamic light scattering ranged from 250 to 300 nm. A loading content of doxorubicin into GC-DOX nanoaggregates as high as 38%, with 97% loading efficiency, could be obtained using a physical entrapment method. A tumor-bearing animal model was developed by inoculating tumor cells into the back of a rat. The FTC-GC nanoaggregates were injected into the tail vein of tumor-bearing rats and their tissue distribution was examined. The FTC-GC nanoaggregates were distributed mainly in kidney, tumor and the liver and were scarcely observed in other tissues. They were maintained at a high level for 8 days and their distribution in tumor tissues increased gradually. This suggests that chitosan nanoaggregates accumulate passively in the tumor tissue due to the enhanced permeability and retention (EPR) effect. Doxorubicin loaded GC-DOX nanoaggregates (DOX/GC-DOX) were injected into the tail vein of tumor-bearing rats and their anti-tumor effect was examined. Tumor growth was suppressed over 10 days.
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Kim YJ, Park CR. Analysis of problematic complexing behavior of ferric chloride with N,N-dimethylformamide using combined techniques of FT-IR, XPS, and TGA/DTG. Inorg Chem 2002; 41:6211-6. [PMID: 12444762 DOI: 10.1021/ic011306p] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A problematic coordination behavior of highly hygroscopic FeCl(3) in DMF solution was studied. From the compositional and structural analyses for the adduct of FeCl(3)/DMF using various techniques such as FTIR, elemental analysis, UV/vis, XPS, and TGA/DTG, it was found that the iron cation exists in the form of an Fe(3+) cation and coordinates via the carbonyl oxygen atom of amide bond in DMF. The analyses of both FT-IR and XPS C 1s spectra for the adduct revealed that 2.1 molecules of DMF coordinate with a more electron-deficient Fe(3+); otherwise 1.2 molecules of DMF coordinated with a relatively electron-rich Fe(3+). The Cl 2p spectrum indicated that the electron-deficient Fe(3+) coordinated with two chlorine ions and the electron-rich Fe(3+) with four chlorines so that the chemical formula of the adduct is of [FeCl(2)(DMF)(1.2)(H(2)O)(2.7)](+)[FeCl(4)(DMF)(2.1)](-). The water molecules in the adduct were found chemisorbed rather than physisorbed, with a singular binding energy.
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Cho YW, Jang J, Park CR, Ko SW. Preparation and solubility in acid and water of partially deacetylated chitins. Biomacromolecules 2002; 1:609-14. [PMID: 11710189 DOI: 10.1021/bm000036j] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Partially deacetylated chitins with different degrees of deacetylation (DD) were prepared by alkaline treatment under homogeneous conditions, and the effect of DD on their solubility was discussed in terms of crystal structure and mode of hydrogen bonding. With an increase in the treatment time, the DD of chitin increased proportionally. The chitin became soluble in dilute acetic acid at the DD of ca. 28% or over and soluble in water at the DD of ca. 49%. The solubility of the partially deacetylated chitins had a close relationship with their crystal structure, crystallinity, and crystal imperfection as well as the glucosamine content. The wide-angle X-ray diffractometry (WAXD) revealed that the chitin with ca. 28% DD retained the crystal structure of alpha-chitin with significantly reduced crystallinity and perfection of the crystallites. The water-soluble chitin of ca. 49% DD had a new crystal structure similar to that of beta-chitin rather than either alpha-chitin or chitosan, suggesting that the homogeneous deacetylation transformed the crystal structure of chitin from the alpha to the beta form. Some hydrogen bonds existing in raw alpha-chitin were found to be missing at a DD of ca. 49%.
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Park CR, Campbell AM, Diamond DM. Chronic psychosocial stress impairs learning and memory and increases sensitivity to yohimbine in adult rats. Biol Psychiatry 2001; 50:994-1004. [PMID: 11750896 DOI: 10.1016/s0006-3223(01)01255-0] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND It is well known that intense and prolonged stress can produce cognitive impairments and hippocampal damage and increase noradrenergic activity in humans. This study investigated the hypothesis that chronic psychosocial stress would affect behavior, drug sensitivity, and hippocampal-dependent learning and memory in rats. The work provides a novel connection between animal and human studies by evaluating the effects of stress on a rat's response to yohimbine, an alpha(2) adrenergic receptor antagonist. METHODS Rats were exposed to a cat for 5 weeks and randomly housed with a different group of cohorts each day (psychosocial stress). The effects of the stress manipulations were then assessed on open field behavior, spatial learning and memory in the radial arm water maze and the behavioral response to a low dose of yohimbine (1.5 mg/kg). RESULTS Stressed rats displayed impaired habituation to a novel environment, heightened anxiety, and increased sensitivity to yohimbine. In addition, the stressed rats exhibited impaired learning and memory. CONCLUSIONS There are commonalities between the current findings on stressed rats and from studies on traumatized people. Thus, psychosocial stress manipulations in rats may yield insight into the basis of cognitive and neuroendocrine disturbances that commonly occur in people with anxiety disorders.
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Kim YH, Gihm SH, Park CR, Lee KY, Kim TW, Kwon IC, Chung H, Jeong SY. Structural characteristics of size-controlled self-aggregates of deoxycholic acid-modified chitosan and their application as a DNA delivery carrier. Bioconjug Chem 2001; 12:932-8. [PMID: 11716684 DOI: 10.1021/bc015510c] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Precise control of the size and structure is one critical design parameter of micellar systems for drug delivery applications. To control the size of self-aggregates, chitosan was depolymerized with various amounts of sodium nitrite, and hydrophobically modified with deoxycholic acid to form self-aggregates in aqueous media. Formation and physicochemical characteristics of size-controlled self-aggregates were investigated using dynamic light scattering, fluorescence spectroscopy, and computer simulation method. The size of self-aggregates varied in the range of 130-300 nm in diameter, and their structures were found to depend strongly on the molecular weight of chitosan ranging from 5 to 200 kDa. Due to the chain rigidity of chitosan molecule, the structure of self-aggregates was suggested to be a cylindrical bamboolike structure when the molecular weight of chitosan was larger than 40 kDa, which might form a very poor spherical form of a birdnestlike structure. To explore the potential applications of self-aggregates as a gene delivery carrier, complexes between chitosan self-aggregates and plasmid DNA were prepared and confirmed by measuring the fluorescence intensity of ethidium bromide and electrophoresis on agarose gels. The complex formation had strong dependency on the size and structure of chitosan self-aggregates and significantly influenced the transfection efficiency of COS-1 cells (up to a factor of 10). This approach to control the size and structure of chitosan-derived self-aggregates may find a wide range of applications in gene delivery as well as general drug delivery applications.
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Abstract
Evidence has been accumulating recently that the hormone insulin may modulate cognitive activity by acting in the central nervous system. Initially derived from the observation that insulin and insulin receptors are found in specific brain areas, this evidence also includes cognitive assessments of humans in insulin-deficient and insulin-resistant disease states and experimental manipulation of rodent models. Additional support is derived from in vivo and in vitro systems that are used to investigate the neurophysiological basis of learning and memory. This article is a brief review of the literature that suggests a connection between insulin and memory and draws together some of the findings relevant to possible physiological mechanisms for this cognitive effect.
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Chang JY, Kim BJ, Park CR, Han MJ, Kim TJ, Yun H. Synthesis and polymerization mechanism of bisacetoacetamides. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/pola.1122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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70
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Kang SJ, Hong SI, Park CR. New film-forming aromatic poly(amide-imide)s containing isoindoloquinazolinedione unit in the backbone. 2. Physical properties of the film cast from poly(biphenylphthalicdianhydride-oxydianiline-4,4?-diamino-3?-carbamoyl-benzanilide) [poly(BPDA-ODA-DACB)]. J Appl Polym Sci 2000. [DOI: 10.1002/1097-4628(20001003)78:1<118::aid-app150>3.0.co;2-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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71
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Diamond DM, Park CR. Predator exposure produces retrograde amnesia and blocks synaptic plasticity. Progress toward understanding how the hippocampus is affected by stress. Ann N Y Acad Sci 2000; 911:453-5. [PMID: 10911891 DOI: 10.1111/j.1749-6632.2000.tb06743.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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72
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Park CR, Seeley RJ, Craft S, Woods SC. Intracerebroventricular insulin enhances memory in a passive-avoidance task. Physiol Behav 2000; 68:509-14. [PMID: 10713291 DOI: 10.1016/s0031-9384(99)00220-6] [Citation(s) in RCA: 259] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Previous studies have indicated a possible enhancing effect of hyperinsulinemia on certain cognitive tasks in human subjects. Further, brain areas important in these tasks have high concentrations of insulin receptors, suggesting that insulin might modulate memory by activity at specific central sites. Extending this observation to the laboratory rat would provide a convenient model system for determining factors important for this possible cognitive effect. The present experiment determined whether intracerebroventricular administration of insulin improves memory formation in rats. Long-Evans rats were trained on a step-through passive-avoidance task, in which they were either shocked or not after entering a darkened compartment. After training, the animals received an intracerebroventricular injection of 4 mU insulin, heat-deactivated insulin or saline vehicle. After 24 h, the animals were tested for retention of the task. Rats receiving insulin after being shocked had an increased latency to enter the dark compartment, compared to those rats that had received saline or heat-deactivated insulin after shock. This difference is consistent with an enhanced memory for the negative consequences of entering.
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Abstract
This series of studies investigated the effects of predator exposure on working memory in rats trained on the radial arm water maze (RAWM). The RAWM is a modified Morris water maze that contains four or six swim paths (arms) radiating out of an open central area, with a hidden platform located at the end of one of the arms. The hidden platform was located in the same arm on each trial within a day and was in a different arm across days. Each day rats learned the location of the hidden platform during acquisition trials, and then the rats were removed from the maze for a 30-min delay period. During the delay period, the rats were placed either in their home cage (nonstress condition) or in close proximity to a cat (stress condition). At the end of the delay period, the rats were run on a retention trial, which tested their ability to remember which arm contained the platform that day. The first experiment confirmed that the RAWM is a hippocampal-dependent task. Rats with hippocampal damage were impaired at learning the location of the hidden platform in the easiest RAWM under control (non-stress) conditions. The next three experiments showed that stress had no effect on memory in the easiest RAWM, but stress did impair memory in more difficult versions of the RAWM. These findings indicate that the capacity for stress to impair memory is influenced not only by the brain memory system involved in solving the task (hippocampal versus nonhippocampal), but also by the difficulty of the task. This work should help to resolve some of the confusion in the literature regarding the heterogeneous effects of stress on hippocampal-dependent learning and memory.
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75
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Diamond DM, Park CR, Heman KL, Rose GM. Exposing rats to a predator impairs spatial working memory in the radial arm water maze. Hippocampus 1999. [PMID: 10560925 DOI: 10.1002/(sici)1098-1063(1999)9:5<542::aid-hipo8>3.0.co;2-n] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This series of studies investigated the effects of predator exposure on working memory in rats trained on the radial arm water maze (RAWM). The RAWM is a modified Morris water maze that contains four or six swim paths (arms) radiating out of an open central area, with a hidden platform located at the end of one of the arms. The hidden platform was located in the same arm on each trial within a day and was in a different arm across days. Each day rats learned the location of the hidden platform during acquisition trials, and then the rats were removed from the maze for a 30-min delay period. During the delay period, the rats were placed either in their home cage (nonstress condition) or in close proximity to a cat (stress condition). At the end of the delay period, the rats were run on a retention trial, which tested their ability to remember which arm contained the platform that day. The first experiment confirmed that the RAWM is a hippocampal-dependent task. Rats with hippocampal damage were impaired at learning the location of the hidden platform in the easiest RAWM under control (non-stress) conditions. The next three experiments showed that stress had no effect on memory in the easiest RAWM, but stress did impair memory in more difficult versions of the RAWM. These findings indicate that the capacity for stress to impair memory is influenced not only by the brain memory system involved in solving the task (hippocampal versus nonhippocampal), but also by the difficulty of the task. This work should help to resolve some of the confusion in the literature regarding the heterogeneous effects of stress on hippocampal-dependent learning and memory.
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