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Ujjainwala AL, Courtney CD, Rhoads SG, Rhodes JS, Christian CA. Genetic loss of diazepam binding inhibitor in mice impairs social interest. Genes Brain Behav 2017; 17:e12442. [PMID: 29193847 DOI: 10.1111/gbb.12442] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/20/2017] [Accepted: 11/23/2017] [Indexed: 01/21/2023]
Abstract
Neuropsychiatric disorders in which reduced social interest is a common symptom, such as autism, depression, and anxiety, are frequently associated with genetic mutations affecting γ-aminobutyric acid (GABA)ergic transmission. Benzodiazepine treatment, acting via GABA type-A receptors, improves social interaction in male mouse models with autism-like features. The protein diazepam binding inhibitor (DBI) can act as an endogenous benzodiazepine, but a role for DBI in social behavior has not been described. Here, we investigated the role of DBI in the social interest and recognition behavior of mice. The responses of DBI wild-type and knockout male and female mice to ovariectomized female wild-type mice (a neutral social stimulus) were evaluated in a habituation/dishabituation task. Both male and female knockout mice exhibited reduced social interest, and DBI knockout mice lacked the sex difference in social interest levels observed in wild-type mice, in which males showed higher social interest levels than females. The ability to discriminate between familiar and novel stimulus mice (social recognition) was not impaired in DBI-deficient mice of either sex. DBI knockouts could learn a rotarod motor task, and could discriminate between social and nonsocial odors. Both sexes of DBI knockout mice showed increased repetitive grooming behavior, but not in a manner that would account for the decrease in social investigation time. Genetic loss of DBI did not alter seminal vesicle weight, indicating that the social interest phenotype of males lacking DBI is not due to reduced circulating testosterone. Together, these studies show a novel role of DBI in driving social interest and motivation.
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Affiliation(s)
- A L Ujjainwala
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - C D Courtney
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - S G Rhoads
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - J S Rhodes
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, Illinois
| | - C A Christian
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
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Hamilton GF, Hernandez IJ, Krebs CP, Bucko PJ, Rhodes JS. Neonatal alcohol exposure reduces number of parvalbumin-positive interneurons in the medial prefrontal cortex and impairs passive avoidance acquisition in mice deficits not rescued from exercise. Neuroscience 2017; 352:52-63. [PMID: 28391014 DOI: 10.1016/j.neuroscience.2017.03.058] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 12/16/2022]
Abstract
Developmental alcohol exposure causes a host of cognitive and neuroanatomical abnormalities, one of which is impaired executive functioning resulting from medial prefrontal cortex (mPFC) damage. This study determined whether third-trimester equivalent alcohol exposure reduced the number of mPFC GABAergic parvalbumin-positive (PV+) interneurons, hypothesized to play an important role in local inhibition of the mPFC. The impact on passive avoidance learning and the therapeutic role of aerobic exercise in adulthood was also explored. Male C57BL/6J mice received either saline or 5g/kg ethanol (two doses, two hours apart) on PD 5, 7, and 9. On PD 35, animals received a running wheel or remained sedentary for 48days before behavioral testing and perfusion on PD 83. The number of PV+ interneurons was stereologically measured in three separate mPFC subregions: infralimbic, prelimbic and anterior cingulate cortices (ACC). Neonatal alcohol exposure decreased number of PV+ interneurons and volume of the ACC, but the other regions of the mPFC were spared. Alcohol impaired acquisition, but not retrieval of passive avoidance, and had no effect on motor performance on the rotarod. Exercise had no impact on PV+ cell number, mPFC volume, or acquisition of passive avoidance, but enhanced retrieval in both control and alcohol-exposed groups, and enhanced rotarod performance in the control mice. Results support the hypothesis that part of the behavioral deficits associated with developmental alcohol exposure are due to reduced PV+ interneurons in the ACC, but unfortunately exercise does not appear to be able to reverse any of these deficits.
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Affiliation(s)
- G F Hamilton
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - I J Hernandez
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - C P Krebs
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - P J Bucko
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - J S Rhodes
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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3
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Saul MC, Majdak P, Perez S, Reilly M, Garland T, Rhodes JS. High motivation for exercise is associated with altered chromatin regulators of monoamine receptor gene expression in the striatum of selectively bred mice. Genes, Brain and Behavior 2016; 16:328-341. [DOI: 10.1111/gbb.12347] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/02/2016] [Accepted: 10/03/2016] [Indexed: 01/12/2023]
Affiliation(s)
- M. C. Saul
- Carl R. Woese Institute for Genomic Biology Urbana IL
| | | | - S. Perez
- The Beckman Institute for Advanced Science and Technology University of Illinois Urbana IL
| | - M. Reilly
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda MD
| | - T. Garland
- Department of Biology University of California Riverside CA
| | - J. S. Rhodes
- Carl R. Woese Institute for Genomic Biology Urbana IL
- The Neuroscience Program
- The Beckman Institute for Advanced Science and Technology University of Illinois Urbana IL
- Department of Psychology University of Illinois Urbana IL USA
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Hamilton GF, Bucko PJ, Miller DS, DeAngelis RS, Krebs CP, Rhodes JS. Behavioral deficits induced by third-trimester equivalent alcohol exposure in male C57BL/6J mice are not associated with reduced adult hippocampal neurogenesis but are still rescued with voluntary exercise. Behav Brain Res 2016; 314:96-105. [PMID: 27491590 DOI: 10.1016/j.bbr.2016.07.052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/21/2016] [Accepted: 07/30/2016] [Indexed: 01/10/2023]
Abstract
Prenatal alcohol exposure can produce permanent alterations in brain structure and profound behavioral deficits. Mouse models can help discover mechanisms and identify potentially useful interventions. This study examined long-term influences of either a single or repeated alcohol exposure during the third-trimester equivalent on survival of new neurons in the hippocampus, behavioral performance on the Passive avoidance and Rotarod tasks, and the potential role of exercise as a therapeutic intervention. C57BL/6J male mice received either saline or 5g/kg ethanol split into two s.c. injections, two hours apart, on postnatal day (PD)7 (Experiment 1) or on PD5, 7 and 9 (Experiment 2). All mice were weaned on PD21 and received either a running wheel or remained sedentary from PD35-PD80/81. From PD36-45, mice received i.p. injections of 50mg/kg bromodeoxyuridine (BrdU) to label dividing cells. Behavioral testing occurred between PD72-79. Number of surviving BrdU+ cells and immature neurons (doublecortin; DCX+) was measured at PD80-81. Alcohol did not affect number of BrdU+ or DCX+ cells in either experiment. Running significantly increased number of BrdU+ and DCX+ cells in both treatment groups. Alcohol-induced deficits on Rotarod performance and acquisition of the Passive avoidance task (Day 1) were evident only in Experiment 2 and running rescued these deficits. These data suggest neonatal alcohol exposure does not result in long-term impairments in adult hippocampal neurogenesis in the mouse model. Three doses of ethanol were necessary to induce behavioral deficits. Finally, the mechanisms by which exercise ameliorated the neonatal alcohol induced behavioral deficits remain unknown.
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Affiliation(s)
- G F Hamilton
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - P J Bucko
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - D S Miller
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - R S DeAngelis
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - C P Krebs
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - J S Rhodes
- Department of Psychology, The Beckman Institute, 405 N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
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Mustroph ML, Pinardo H, Merritt JR, Rhodes JS. Parameters for abolishing conditioned place preference for cocaine from running and environmental enrichment in male C57BL/6J mice. Behav Brain Res 2016; 312:366-73. [PMID: 27363922 DOI: 10.1016/j.bbr.2016.06.049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/21/2016] [Accepted: 06/26/2016] [Indexed: 12/21/2022]
Abstract
RATIONALE Evidence suggests that 4 weeks of voluntary wheel running abolishes conditioned place preference (CPP) for cocaine in male C57BL/6J mice. OBJECTIVES To determine the duration and timing of exposure to running wheels necessary to reduce CPP, and the extent to which the running per se influences CPP as compared to environmental enrichment without running. METHODS A total of 239 males were conditioned for 4days twice daily with cocaine (10mg/kg) and then split into 7 intervention groups prior to 4days of CPP testing. Experiment 1 consisted of two groups housed as follows: short sedentary group (SS; n=20) in normal cages for 1 week; the short running group (SR; n=20) with running wheels for 1 week. Experiment 2 consisted of five groups housed as follows; short 1 week of running followed by a 3 week sedentary period (SRS; n=20); a 3 week sedentary period followed by 1 week of running (SSR; n=20); long sedentary group (LS; n=66) in normal cages for 4 weeks; long running group (LR; n=66) with running wheels for 4 weeks; and long environmental enrichment group (EE; n=27) with toys for 4 weeks. RESULTS Levels of running were similar in all running groups. Both running and environmental enrichment reduced CPP relative to sedentary groups. CONCLUSIONS Results suggest that the abolishment of cocaine CPP from running is robust and occurs with as low as 1 week of intervention but may be related to enrichment component of running rather than physical activity.
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Affiliation(s)
- M L Mustroph
- University of Illinois at Urbana-Champaign, Beckman Institute of Advanced Science and Technology, 405 N. Mathews Avenue, Urbana, IL 61801, USA.
| | - H Pinardo
- University of Illinois at Urbana-Champaign, Beckman Institute of Advanced Science and Technology, 405 N. Mathews Avenue, Urbana, IL 61801, USA
| | - J R Merritt
- University of Illinois at Urbana-Champaign, Beckman Institute of Advanced Science and Technology, 405 N. Mathews Avenue, Urbana, IL 61801, USA
| | - J S Rhodes
- University of Illinois at Urbana-Champaign, Beckman Institute of Advanced Science and Technology, 405 N. Mathews Avenue, Urbana, IL 61801, USA
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Abstract
A better understanding of endodontic disease and the causes of treatment failure has refined the role of surgery in endodontics. The advent of newer materials, advances in surgical armamentarium and techniques have also led to an improved endodontic surgical outcome. The aim of this article is to provide a contemporary and up-to-date overview of endodontic surgery. It will focus primarily on the procedures most commonly performed in endodontic surgery.
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Affiliation(s)
- B S Chong
- Professor/Honorary Consultant in Restorative Dentistry, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London
| | - J S Rhodes
- Specialist in Endodontics, Poole, Dorset
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Hamilton GF, Majdak P, Miller DS, Bucko PJ, Merritt JR, Krebs CP, Rhodes JS. Evaluation of a C57BL/6J × 129S1/SvImJ Hybrid Nestin-Thymidine Kinase Transgenic Mouse Model for Studying the Functional Significance of Exercise-Induced Adult Hippocampal Neurogenesis. Brain Plast 2015; 1:83-95. [PMID: 28989863 PMCID: PMC5627510 DOI: 10.3233/bpl-150011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
New neurons are continuously generated in the adult hippocampus but their function remains a mystery. The nestin thymidine kinase (nestin-TK) transgenic method has been used for selective and conditional reduction of neurogenesis for the purpose of testing the functional significance of new neurons in learning, memory and motor performance. Here we explored the nestin-TK model on a hybrid genetic background (to increase heterozygosity, and “hybrid vigor”). Transgenic C57BL/6J (B6) were crossed with 129S1/SvImJ (129) producing hybrid offspring (F1) with the B6 half of the genome carrying a herpes simplex virus thymidine kinase (TK) transgene regulated by a modified nestin promoter. In the presence of exogenously administered valganciclovir, new neurons expressing TK undergo apoptosis. Female B6 nestin-TK mice (n = 80) were evaluated for neurogenesis reduction as a positive control. Male and female F1 nestin-TK mice (n = 223) were used to determine the impact of neurogenesis reduction on the Morris water maze (MWM) and rotarod. All mice received BrdU injections to label dividing cells and either valganciclovir or control chow, with or without a running wheel for 30 days. Both the F1 and B6 background displayed approximately 50% reduction in neurogenesis, a difference that did not impair learning and memory on the MWM or rotarod performance. Running enhanced neurogenesis and performance on the rotarod but not MWM suggesting the F1 background may not be suitable for studying pro-cognitive effects of exercise on MWM. Greater reduction of neurogenesis may be required to observe behavioral impacts. Alternatively, new neurons may not play a critical role in learning, or compensatory mechanisms in pre-existing neurons could have masked the deficits. Further work using these and other models for selectively reducing neurogenesis are needed to establish the functional significance of adult hippocampal neurogenesis in behavior.
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Affiliation(s)
- G F Hamilton
- Department of Psychology, The Beckman Institute, 405N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - P Majdak
- Department of Psychology, The Beckman Institute, 405N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - D S Miller
- Department of Psychology, The Beckman Institute, 405N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - P J Bucko
- Department of Psychology, The Beckman Institute, 405N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - J R Merritt
- Department of Psychology, The Beckman Institute, 405N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - C P Krebs
- Department of Psychology, The Beckman Institute, 405N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - J S Rhodes
- Department of Psychology, The Beckman Institute, 405N Mathews Ave, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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Mustroph ML, Merritt JR, Holloway AL, Pinardo H, Miller DS, Kilby CN, Bucko P, Wyer A, Rhodes JS. Increased adult hippocampal neurogenesis is not necessary for wheel running to abolish conditioned place preference for cocaine in mice. Eur J Neurosci 2015; 41:216-26. [PMID: 25393660 PMCID: PMC4300275 DOI: 10.1111/ejn.12782] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/13/2014] [Indexed: 01/18/2023]
Abstract
Recent evidence suggests that wheel running can abolish conditioned place preference (CPP) for cocaine in mice. Running significantly increases the number of new neurons in the hippocampus, and new neurons have been hypothesised to enhance plasticity and behavioral flexibility. Therefore, we tested the hypothesis that increased neurogenesis was necessary for exercise to abolish cocaine CPP. Male nestin-thymidine kinase transgenic mice were conditioned with cocaine, and then housed with or without running wheels for 32 days. Half of the mice were fed chow containing valganciclovir to induce apoptosis in newly divided neurons, and the other half were fed standard chow. For the first 10 days, mice received daily injections of bromodeoxyuridine (BrdU) to label dividing cells. On the last 4 days, mice were tested for CPP, and then euthanized for measurement of adult hippocampal neurogenesis by counting the number of BrdU-positive neurons in the dentate gyrus. Levels of running were similar in mice fed valganciclovir-containing chow and normal chow. Valganciclovir significantly reduced the numbers of neurons (BrdU-positive/NeuN-positive) in the dentate gyrus of both sedentary mice and runner mice. Valganciclovir-fed runner mice showed similar levels of neurogenesis as sedentary, normal-fed controls. However, valganciclovir-fed runner mice showed the same abolishment of CPP as runner mice with intact neurogenesis. The results demonstrate that elevated adult hippocampal neurogenesis resulting from running is not necessary for running to abolish cocaine CPP in mice.
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Affiliation(s)
- M L Mustroph
- Beckman Institute, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL, 61801, USA; Neuroscience Program, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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Dabe EC, Majdak P, Bhattacharya TK, Miller DS, Rhodes JS. Chronic D-amphetamine administered from childhood to adulthood dose-dependently increases the survival of new neurons in the hippocampus of male C57BL/6J mice. Neuroscience 2012. [PMID: 23178911 DOI: 10.1016/j.neuroscience.2012.11.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Adderall is widely prescribed for attention deficit hyperactivity disorder (ADHD) though long term neurological effects of the main ingredient d-amphetamine are not well understood. The purpose of this study was to examine effects of clinically prescribed doses of d-amphetamine and one abuse dose administered from childhood to adulthood on adult hippocampal neurogenesis and activation of the granule layer of the dentate gyrus. Beginning in early adolescence (age 28 days) to adulthood (age 71), male C57BL/6J mice were administered twice daily i.p. injections of vehicle, 0.25, 0.5 or 2mg/kg d-amphetamine. Locomotor activity was measured in home cages by video tracking. At age 53-56, mice received bromodeoxyuridine (BrdU) injections to label dividing cells. Immunohistochemical detection of BrdU, neuronal nuclear protein (NeuN), doublecortin (DCX) and Ki67 was used to measure neurogenesis and cell proliferation at age 71. ΔFosB was measured as an indicator of repeated neuronal activation. An additional cohort of mice was treated similarly except euthanized at age 58 to measure activation of granule neurons from d-amphetamine (by detection of c-Fos) and cell proliferation (Ki67) at a time when the fate of BrdU cells would have been determined in the first cohort. d-Amphetamine dose-dependently increased survival and differentiation of BrdU cells into neurons and increased number of DCX cells without affecting the number of Ki67 cells. Low doses of d-amphetamine decreased c-Fos and ΔFosB in the granule layer. Only the high dose induced substantial locomotor stimulation and sensitization. Results suggest both therapeutic and abuse doses of d-amphetamine increase the number of new neurons in the hippocampus when administered from adolescence to adulthood by increasing survival and differentiation of cells into neurons not by increasing progenitor cell proliferation. Mechanisms for amphetamine-induced neurogenesis are unknown but appear activity independent. Results suggest part of the beneficial effects of therapeutic doses of d-amphetamine for ADHD could be via increased hippocampal neurogenesis.
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Affiliation(s)
- E C Dabe
- Department of Psychology, The Beckman Institute, 405 N Mathews Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Mustroph ML, Chen S, Desai SC, Cay EB, DeYoung EK, Rhodes JS. Aerobic exercise is the critical variable in an enriched environment that increases hippocampal neurogenesis and water maze learning in male C57BL/6J mice. Neuroscience 2012; 219:62-71. [PMID: 22698691 DOI: 10.1016/j.neuroscience.2012.06.007] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 06/01/2012] [Accepted: 06/04/2012] [Indexed: 10/28/2022]
Abstract
Previous studies have shown that housing mice with toys and running wheels increases adult hippocampal neurogenesis and enhances performance on the water maze. However, the relative contribution of running versus enrichment to the neurogenic and pro-cognitive effects is not clear. Recently, it was demonstrated that enrichment devoid of running wheels does not significantly enhance adult hippocampal neurogenesis in female C57BL/6J mice. However, novel toys were not rotated into the cages, and dietary enrichment was not included, so it could be argued that the environment was not enriched enough. In addition, only females were studied, and animals were group-housed, making it impossible to record individual running behavior or to determine the time spent running versus exploring the toys. Therefore, we repeated the study in singly housed male C57BL/6J mice and enhanced enrichment by rotating novel tactile, visual, dietary, auditory, and vestibular stimuli into the cages. Mice were housed for 32 days in one of four groups: running-only, enrichment-only, running plus enrichment, and standard cage. The first 10 days bromodeoxyuridine (BrdU) was administered to label dividing cells. The last 5 days mice were tested on the water maze, and then euthanized to measure number of BrdU cells co-labeled with neuronal nuclear marker (NeuN) in the dentate gyrus. Mice in the running-only group ran, on average, equivalent distances as animals in the running plus enrichment group. The combination of enrichment and running did not significantly increase hippocampal neurogenesis any more than running alone did. Animals in the running-only condition were the only group to show enhanced acquisition on water maze relative to standard cage controls. We confirm and extend the conclusion that environmental enrichment alone does not significantly increase hippocampal neurogenesis or bestow spatial learning benefits in male C57BL/6J mice, even when the modalities of enrichment are very broad.
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Affiliation(s)
- M L Mustroph
- Neuroscience Program, The Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Zombeck JA, Swearingen SP, Rhodes JS. Acute locomotor responses to cocaine in adolescents vs. adults from four divergent inbred mouse strains. Genes Brain Behav 2011; 9:892-8. [PMID: 20662938 DOI: 10.1111/j.1601-183x.2010.00630.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Growing evidence suggests that adolescent mice display differential sensitivity to the acute locomotor activating effects of cocaine as compared to adults, but the direction of the difference varies across studies and the reasons are not clear. Few studies have directly examined genetic contributions to age differences in locomotor stimulation from cocaine. The goal of this study was to determine the extent to which reduced stimulation in C57BL/6J adolescents as compared to adults generalizes to other strains. Therefore, we examined male and female mice from four genetically divergent inbred stains (BALB/cByJ, C57BL/6J, DBA/2J and FVB/NJ) at two ages, postnatal day 30 and postnatal day 65. Mice received either saline or cocaine (15 or 30 mg/kg), and then immediately were placed back into their home cages. Locomotor activity was recorded continuously in the home cage by video tracking. Adolescents displayed reduced stimulation as compared to adults for C57BL/6J, BALB/cByJ and female FVB/NJ mice. No age differences were observed for DBA/2J or male FVB/NJ. No main effects of sex were observed. Strain differences in pharmacokinetics, neural development or physiology could contribute to the observed differences between ages across strains. Future comparative studies could discover biological differences between strains that explain age differences in cocaine sensitivity.
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Affiliation(s)
- J A Zombeck
- Department of Psychology, The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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12
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Clark PJ, Kohman RA, Miller DS, Bhattacharya TK, Brzezinska WJ, Rhodes JS. Genetic influences on exercise-induced adult hippocampal neurogenesis across 12 divergent mouse strains. Genes Brain Behav 2011; 10:345-53. [PMID: 21223504 DOI: 10.1111/j.1601-183x.2010.00674.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
New neurons are continuously born in the hippocampus of several mammalian species throughout adulthood. Adult neurogenesis represents a natural model for understanding how to grow and incorporate new nerve cells into preexisting circuits in the brain. Finding molecules or biological pathways that increase neurogenesis has broad potential for regenerative medicine. One strategy is to identify mouse strains that display large vs. small increases in neurogenesis in response to wheel running so that the strains can be contrasted to find common genes or biological pathways associated with enhanced neuron formation. Therefore, mice from 12 different isogenic strains were housed with or without running wheels for 43 days to measure the genetic regulation of exercise-induced neurogenesis. During the first 10 days mice received daily injections of 5-bromo-2'-deoxyuridine (BrdU) to label dividing cells. Neurogenesis was measured as the total number of BrdU cells co-expressing NeuN mature neuronal marker in the hippocampal granule cell layer by immunohistochemistry. Exercise increased neurogenesis in all strains, but the magnitude significantly depended on genotype. Strain means for distance run on wheels, but not distance traveled in cages without wheels, were significantly correlated with strain mean level of neurogenesis. Furthermore, certain strains displayed greater neurogenesis than others for a fixed level of running. Strain means for neurogenesis under sedentary conditions were not correlated with neurogenesis under runner conditions suggesting that different genes influence baseline vs. exercise-induced neurogenesis. Genetic contributions to exercise-induced hippocampal neurogenesis suggest that it may be possible to identify genes and pathways associated with enhanced neuroplastic responses to exercise.
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Affiliation(s)
- P J Clark
- Department of Psychology, University of Illinois, Beckman Institute, Urbana, IL 61801, USA.
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13
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Zombeck JA, Lewicki AD, Patel K, Gupta T, Rhodes JS. Patterns of neural activity associated with differential acute locomotor stimulation to cocaine and methamphetamine in adolescent versus adult male C57BL/6J mice. Neuroscience 2009; 165:1087-99. [PMID: 19932887 DOI: 10.1016/j.neuroscience.2009.11.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 11/12/2009] [Accepted: 11/17/2009] [Indexed: 10/20/2022]
Abstract
Adolescence is a time period when major changes occur in the brain with long-term consequences for behavior. One ramification is altered responses to drugs of abuse, but the specific brain mechanisms and implications for mental health are poorly understood. Here, we used a mouse model in which adolescents display dramatically reduced sensitivity to the acute locomotor stimulating effects of cocaine and methamphetamine. The goal was to identify key brain regions or circuits involved in the differential behavior. Male adolescent (postnatal day (PN), 30-35) and young adult (PN, 69-74) C57BL/6J mice were administered an i.p. injection of cocaine (0, 15, 30 mg/kg) or methamphetamine (0, 2, 4 mg/kg) and euthanized 90 min later. Locomotor activity was monitored continuously in the home cage by video tracking. Immunohistochemical detection of Fos protein was used to quantify neuronal activation in 16 different brain regions. As expected, adolescents were less sensitive to the locomotor stimulating effects of cocaine and methamphetamine as indicated by a rightward shift in the dose response relationship. After a saline injection, adolescents showed similar levels of Fos as adults in all regions except the dorsal caudate (CPuD) and lateral caudate (CPuL) where levels were lower in adolescents. Cocaine and methamphetamine dose dependently increased Fos in all brain regions sampled in both adolescents and adults, but Fos levels were similar in both age groups for a majority of regions and doses. Locomotor activity was correlated with Fos in several brain areas within adolescent and adult groups, and adolescents had a significantly greater induction of Fos for a given amount of locomotor activity in key brain regions including the caudate where they showed reduced Fos under baseline conditions. Future research will identify the molecular and cellular events that are responsible for the differential psychostimulant-induced patterns of brain activation and behavior observed in adolescent versus adult mice.
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Affiliation(s)
- J A Zombeck
- Department of Psychology, The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Clark PJ, Brzezinska WJ, Thomas MW, Ryzhenko NA, Toshkov SA, Rhodes JS. Intact neurogenesis is required for benefits of exercise on spatial memory but not motor performance or contextual fear conditioning in C57BL/6J mice. Neuroscience 2008; 155:1048-58. [PMID: 18664375 DOI: 10.1016/j.neuroscience.2008.06.051] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 06/21/2008] [Accepted: 06/23/2008] [Indexed: 12/18/2022]
Abstract
The mammalian hippocampus continues to generate new neurons throughout life. Experiences such as exercise, anti-depressants, and stress regulate levels of neurogenesis. Exercise increases adult hippocampal neurogenesis and enhances behavioral performance on rotarod, contextual fear and water maze in rodents. To directly test whether intact neurogenesis is required for gains in behavioral performance from exercise in C57BL/6J mice, neurogenesis was reduced using focal gamma irradiation (3 sessions of 5 Gy). Two months after treatment, mice (total n=42 males and 42 females) (Irradiated or Sham), were placed with or without running wheels (Runner or Sedentary) for 54 days. The first 10 days mice received daily injections of bromodeoxyuridine (BrdU) to label dividing cells. The last 14 days mice were tested on water maze (two trials per day for 5 days, then 1 h later probe test), rotarod (four trials per day for 3 days), and contextual fear conditioning (2 days), then measured for neurogenesis using immunohistochemical detection of BrdU and neuronal nuclear protein (NeuN) mature neuronal marker. Consistent with previous studies, in Sham animals, running increased neurogenesis fourfold and gains in performance were observed for the water maze (spatial learning and memory), rotarod (motor performance), and contextual fear (conditioning). These positive results provided the reference to determine whether gains in performance were blocked by irradiation. Irradiation reduced neurogenesis by 50% in both groups, Runner and Sedentary. Irradiation did not affect running or baseline performance on any task. Minimal changes in microglia associated with inflammation (using immunohistochemical detection of cd68) were detected at the time of behavioral testing. Irradiation did not reduce gains in performance on rotarod or contextual fear, however it eliminated gain in performance on the water maze. Results support the hypothesis that intact exercise-induced hippocampal neurogenesis is required for improved spatial memory, but not motor performance or contextual fear in C57BL/6J mice.
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Affiliation(s)
- P J Clark
- Department of Psychology, The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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15
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Kamdar NK, Miller SA, Syed YM, Bhayana R, Gupta T, Rhodes JS. Acute effects of naltrexone and GBR 12909 on ethanol drinking-in-the-dark in C57BL/6J mice. Psychopharmacology (Berl) 2007; 192:207-17. [PMID: 17273875 DOI: 10.1007/s00213-007-0711-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 01/13/2007] [Indexed: 10/23/2022]
Abstract
RATIONALE Recently, a simple procedure was described, drinking in the dark (DID), in which C57BL/6J mice self-administer ethanol to the point of intoxication. The test consists of replacing the water with 20% ethanol in the home cage for 2 or 4 h early during the dark phase of the light/dark cycle. OBJECTIVES To determine whether the model displays predictive validity with naltrexone, and whether opioid or dopaminergic mechanisms mediate excessive drinking in the model. MATERIALS AND METHODS Naltrexone or GBR 12909 were administered via intraperitoneal injections immediately before offering ethanol solutions, plain tap water, or 10% sugar water to male C57BL/6J mice, and consumption was monitored over a 2- or 4-h period using the DID procedure. RESULTS Naltrexone (0.5, 1, or 2 mg/kg) dose dependently decreased ethanol drinking but these same doses had no significant effect on the consumption of plain water or 10% sugar water. GBR 12909 (5, 10, and 20 mg/kg) dose dependently reduced the consumption of ethanol and sugar water but had no effect on plain water drinking. CONCLUSIONS The DID model demonstrates predictive validity. Both opioid and dopamine signaling are involved in ethanol drinking to intoxication. Different physiological pathways mediate high ethanol drinking as compared to water or sugar water drinking in DID. DID may be a useful screening tool to find new alcoholism medications and to discover genetic and neurobiological mechanisms relevant to the human disorder.
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Affiliation(s)
- N K Kamdar
- Department of Psychology, Beckman Institute, Urbana, IL 61801, USA
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16
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Abstract
Recently, we described a simple procedure, Drinking in the Dark (DID), in which C57BL/6J mice self-administer ethanol to a blood ethanol concentration (BEC) above 1 mg/ml. The test consists of replacing the water with 20% ethanol in the home cage for 4 h early during the dark phase of the light/dark cycle. Three experiments were conducted to explore this high ethanol drinking model further. In experiment 1, a microanalysis of C57BL/6J behavior showed that the pattern of ethanol drinking was different from routine water intake. In experiment 2, drinking impaired performance of C57BL/6J on the accelerating rotarod and balance beam. In experiment 3, 12 inbred strains were screened to estimate genetic influences on DID and correlations with other traits. Large, reliable differences in intake and BEC were detected among the strains, with C57BL/6J showing the highest values. Strain means were positively correlated with intake and BEC in the standard (24 h) and a limited (4 h) two-bottle ethanol vs. water test, but BECs reached higher levels for DID. Strain mean correlations with other traits in the Mouse Phenome Project database supported previously reported genetic relationships of high ethanol drinking with low chronic ethanol withdrawal severity and low ethanol-conditioned taste aversion. We extend these findings by showing that the correlation estimates remain relatively unchanged even after correcting for phylogenetic relatedness among the strains, thus relaxing the assumption that the strain means are statistically independent. We discuss applications of the model for finding genes that predispose pharmacologically significant drinking in mice.
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Affiliation(s)
- J S Rhodes
- Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
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Bronikowski AM, Rhodes JS, Garland T, Prolla TA, Awad TA, Gammie SC. The evolution of gene expression in mouse hippocampus in response to selective breeding for increased locomotor activity. Evolution 2004; 58:2079-86. [PMID: 15521463 DOI: 10.1111/j.0014-3820.2004.tb00491.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The evolution of behavior has been notoriously difficult to study at the molecular level, but mouse genetic technology offers new promise. We applied selective breeding to increase voluntary wheel running in four replicate lines of Mus domesticus (S mice) while maintaining four additional lines through random breeding to serve as controls (C mice). The goal of the study was to identify the gene expression profile of the hippocampus that may have evolved to facilitate the increased voluntary running. The hippocampus was of interest because it is known to display marked physiological responses in association with wheel running itself. We used high-density oligonucleotide arrays representing 11,904 genes. To control for the confounding influence of physical activity itself on gene expression, animals were housed individually without access to running wheels, and were sampled during the day when they are normally inactive. Two-month-old female mice in estrus were used (n = 16 total; two per line; 8 S and 8 C). After correcting for an acceptable false discovery rate (10%), 30 genes, primarily involved in transcription and translation, significantly increased expression whereas 23 genes, distributed among many categories including immune function and neuronal signaling, decreased expression in S versus C mice. These changes were relatively small in magnitude relative to the changes in gene expression that occur in the hippocampus in response to wheel running itself. A priori tests of dopamine receptor expression levels demonstrated an increase of approximately 20% in the expression of D2 and D4 receptors. These results suggest that relatively small changes in the expression patterns of hippocampal genes underlie large changes in phenotypic response to selection, and that the genetic architecture of running motivation likely involves the dopaminergic system as well as CNS signaling machinery.
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Affiliation(s)
- A M Bronikowski
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011, USA.
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Sharpe ED, Day DG, Beischel CJ, Rhodes JS, Stewart JA, Stewart WC. Brimonidine purite 0.15% versus dorzolamide 2% each given twice daily to reduce intraocular pressure in subjects with open angle glaucoma or ocular hypertension. Br J Ophthalmol 2004; 88:953-6. [PMID: 15205246 PMCID: PMC1772220 DOI: 10.1136/bjo.2003.032979] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS To evaluate the efficacy of brimonidine purite versus dorzolamide given twice daily in primary open angle glaucoma or ocular hypertensive subjects. METHODS In this double masked, multicentre, prospective, crossover comparison 33 subjects were randomised to brimonidine purite or dorzolamide for the first 4 week treatment period after a 4 week washout. Subjects began the opposite treatment for the second 4 week period after another 4 week washout. Intraocular pressure (IOP) was measured at 08:00 (trough) and 10:00, 18:00, and 20:00 hours after dosing at each baseline and at the end of each treatment period. RESULTS The baseline diurnal IOP was 22.9 (SD 2.8) for brimonidine purite and 22.2 (SD 2.4) mm Hg for dorzolamide. The trough IOP following 4 weeks of therapy was 21.0 (SD 3.7) for brimonidine purite and 21.0 (SD 3.1) mm Hg for dorzolamide (p = 0.90). The mean diurnal IOP was 19.3 (SD 3.1) for brimonidine purite and 19.8 (SD 2.4) mm Hg for dorzolamide (p = 0.46). Dorzolamide caused more ocular stinging upon instillation (n = 8) than brimonidine purite (n = 1) (p = 0.02). No statistical differences existed between groups for systemic adverse events. CONCLUSIONS This study suggests that brimonidine purite and dorzolamide each given twice daily have similar efficacy in primary open angle glaucoma or ocular hypertensive subjects. However, a trend was observed at 10:00 of greater brimonidine purite efficacy compared with dorzolamide.
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Affiliation(s)
- E D Sharpe
- Opthalmology Consultants, Mt Pleasant, SC, USA
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19
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Abstract
Root canal retreatment is often the preferred method of treating a tooth in which root canal treatment has failed. Part one of this two-part article discusses reasons for failure of root canal treatment, case assessment and treatment planning. Part two describes some of the practical techniques that are available to the practitioner and the rationale for root canal retreatment.
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Affiliation(s)
- T R Ford
- Department of Conservative Dentistry, Guy's, King's and St. Thomas' Dental Institute, King's College, London
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20
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Abstract
Root canal retreatment is often the preferred method of treating a tooth in which root canal treatment has failed. Part two of this two-part article discusses the rationale for root canal retreatment and practical techniques and equipment that are available to practitioners.
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Affiliation(s)
- T R Ford Ford
- Department of Conservative Dentistry, Guy's, King's and St. Thomas' Dental Institute, King's College London, London SEI
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21
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Bronikowski AM, Rhodes JS, Garland T, Prolla TA, Awad TA, Gammie SC. THE EVOLUTION OF GENE EXPRESSION IN MOUSE HIPPOCAMPUS IN RESPONSE TO SELECTIVE BREEDING FOR INCREASED LOCOMOTOR ACTIVITY. Evolution 2004. [DOI: 10.1554/04-102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Johnson RA, Rhodes JS, Jeffrey SL, Garland T, Mitchell GS. Hippocampal brain-derived neurotrophic factor but not neurotrophin-3 increases more in mice selected for increased voluntary wheel running. Neuroscience 2003; 121:1-7. [PMID: 12946694 DOI: 10.1016/s0306-4522(03)00422-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Voluntary wheel running in rats increases hippocampal brain-derived neurotrophic factor (BDNF) expression, a neurochemical important for neuronal survival, differentiation, connectivity and synaptic plasticity. Here, we report the effects of wheel running on BDNF and neurotrophin-3 (NT-3) protein levels in normal control mice, and in mice selectively bred (25 generations) for increased voluntary wheel running. We hypothesized that increased voluntary wheel running in selected (S) mice would increase CNS BDNF and NT-3 protein levels more than in control (C) mice. Baseline hippocampal BDNF levels (mice housed without running wheels) were similar in S and C mice. Following seven nights of running, hippocampal BDNF increased significantly more in S versus C mice, and levels were correlated with distance run (considering C and S mice together). Spinal and cerebellar BDNF and hippocampal NT-3 levels were not significantly affected by wheel running in any group, but there was a small, positive correlation between spinal C3-C6 BDNF levels and distance run (considering C and S mice together). This is the first study to demonstrate that mice which choose to run more have greater elevations in hippocampal BDNF, suggesting enhanced potential for exercise-induced hippocampal neuroplasticity.
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Affiliation(s)
- R A Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive, Madison, WI 53706, USA
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23
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Robinson AL, Rhodes JS, Keith DW. Assessment of potential carbon dioxide reductions due to biomass-coal cofiring in the United States. Environ Sci Technol 2003; 37:5081-5089. [PMID: 14655692 DOI: 10.1021/es034367q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cofiring biomass with coal in existing power plants offers a relatively inexpensive and efficient option for increasing near-term biomass energy utilization. Potential benefits include reduced emissions of carbon dioxide, sulfur, and nitrogen oxides and development of biomass energy markets. To understand the economics of this strategy, we develop a model to calculate electricity and pollutant mitigation costs with explicit characterization of uncertainty in fuel and technology costs and variability in fuel properties. The model is first used to evaluate the plant-level economics of cofiring as a function of biomass cost. It is then integrated with state-specific coal consumption and biomass supply estimates to develop national supply curves for cofire electricity and carbon mitigation. A delivered cost of biomass below 15 dollars per ton is required for cofire to be competitive with existing coal-based generation. Except at low biomass prices (less than 15 dollars per ton), cofiring is unlikely to be competitive for NOx or SOx control, but it can provide comparatively inexpensive control of CO2 emissions: we estimate that emissions reductions of 100 Mt-CO2/year (a 5% reduction in electric-sector emissions) can be achieved at 25 +/- 20 dollars/tC. The 2-3 year time horizon for deployment--compared with 10-20 years for other CO2 mitigation options--makes cofiring particularly attractive.
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Affiliation(s)
- A L Robinson
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213-3890, USA.
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24
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Crabbe JC, Cotnam CJ, Cameron AJ, Schlumbohm JP, Rhodes JS, Metten P, Wahlsten D. Strain differences in three measures of ethanol intoxication in mice: the screen, dowel and grip strength tests. Genes Brain Behav 2003; 2:201-13. [PMID: 12953786 DOI: 10.1034/j.1601-183x.2003.00023.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mice from 8 to 21 inbred strains were tested for sensitivity to ethanol intoxication using a range of doses and three different measures: the screen test, the dowel test and a test of grip strength. Strains differed under nearly all conditions. For the dowel test, two dowel widths were employed, and mice were tested immediately or 30 min after ethanol. For the dowel and screen tests, low doses failed to affect some strains, and the highest doses failed to discriminate among mice, maximally affecting nearly all. For grip strength, a single ethanol dose was used, and mice of all strains were affected. Pharmacokinetic differences among strains were significant, but these could not account for strain differences in intoxication. For doses and test conditions in the middle range, there were only modest correlations among strain means within a test. In addition, genotypic correlations across tests were modest to quite low. These results suggest that different specific versions of a test reflect the influence of different genes, and that genetic influences on different tests were also distinct.
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Affiliation(s)
- J C Crabbe
- Portland Alcohol Research Center, Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA.
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25
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Rhodes JS, Garland T. Differential sensitivity to acute administration of Ritalin, apomorphine, SCH 23390, but not raclopride in mice selectively bred for hyperactive wheel-running behavior. Psychopharmacology (Berl) 2003; 167:242-50. [PMID: 12669177 DOI: 10.1007/s00213-003-1399-9] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2002] [Accepted: 12/04/2002] [Indexed: 11/30/2022]
Abstract
RATIONALE Previous studies of mice ( Mus domesticus) selectively bred for high voluntary wheel running have suggested that the hyperactivity is associated with dysfunction in the dopaminergic neuromodulatory system and that high-running mice may represent a useful genetic model for attention deficit hyperactivity disorder (ADHD). OBJECTIVES We tested the hypothesis that mice from the four replicate hyperactive lines would respond differently to methylphenidate (Ritalin), apomorphine (non-selective dopamine agonist), SCH 23390 (selective D1-like dopamine antagonist), and raclopride (selective D2-like dopamine antagonist) than individuals from the four replicate, randomly bred, control lines. METHODS After animals were habituated (3 weeks) to their cages with attached wheels, drugs were administered via intraperitoneal injections, at night, during peak wheel-running activity. Revolutions on wheels 10-70 min post-injection were used to quantify drug responses. RESULTS Ritalin (15 mg/kg and 30 mg/kg) increased wheel running in control lines but decreased running in selected lines. A low-dose (0.125 mg/kg) of apomorphine reduced wheel running by a similar amount in control and selected lines; however, higher doses of apomorphine (0.25 mg/kg and 0.5 mg/kg) produced greater reductions in wheel running in the control lines. SCH 23390 (0.025, 0.05, and 0.1 mg/kg) caused greater reductions in wheel running in control than in selected lines. Raclopride (0.5, 1, and 2 mg/kg) reduced wheel running by a similar amount in control and selected lines. CONCLUSIONS These results support the interpretation that genetically determined hyperactive wheel-running behavior is associated with altered dopaminergic function in this mouse model. More specifically, results suggest that D1-like (D1 or D5), but not D2-like (D2, D3, or D4), dopamine receptors have reduced function in the high-running mice. The fact that Ritalin decreased wheel running in selected lines further supports their use as an animal model of ADHD.
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Affiliation(s)
- J S Rhodes
- Department of Zoology, University of Wisconsin, Madison 53706, USA.
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Girard I, McAleer MW, Rhodes JS, Garland T. Selection for high voluntary wheel-running increases speed and intermittency in house mice (Mus domesticus). J Exp Biol 2001; 204:4311-20. [PMID: 11815655 DOI: 10.1242/jeb.204.24.4311] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
In nature, many animals use intermittent rather than continuous locomotion. In laboratory studies, intermittent exercise regimens have been shown to increase endurance compared with continuous exercise. We hypothesized that increased intermittency has evolved in lines of house mice (Mus domesticus) that have been selectively bred for high voluntary wheel-running (wheel diameter 1.12 m) activity. After 23 generations, female mice from four replicate selection lines ran 2.7 times more revolutions per day than individuals from four random-bred control lines. To measure instantaneous running speeds and to quantify intermittency, we videotaped mice (N=41) during a 5-min period of peak activity on night 6 of a 6-day exposure to wheels. Compared with controls (20 revs min–1 while actually running), selection-line females (41 revs min–1) ran significantly faster. These instantaneous speeds closely matched the computer-recorded speeds over the same 5-min period. Selection-line females also ran more intermittently, with shorter (10.0 s bout–1) and more frequent (7.8 bouts min–1) bouts than controls (16.8 s bout–1, 3.4 bouts min–1). Inter-bout pauses were also significantly shorter in selection-line (2.7 s) than in control-line (7.4 s) females. We hypothesize that intermittency of locomotion is a key feature allowing the increased wheel-running performance at high running speeds in selection-line mice.
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Affiliation(s)
- I Girard
- Department of Zoology, 430 Lincoln Drive, University of Wisconsin-Madison, Madison, WI 53706, USA.
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27
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Abstract
AIM The aim of this case report is to describe conventional root canal treatment on a mandibular second premolar with four canals. SUMMARY The pulp of a mandibular second premolar had become irreversibly inflamed, probably as a result of bacterial microleakage from a carious lesion. The general dental practitioner had initiated root canal treatment, but due to procedural difficulties referred the case. Conventional root canal treatment was then performed with magnification. Preparation was undertaken in a crown-down manner using balanced force hand instrumentation with flexible K-type files and files of Greater Taper. The root canals were obturated with vertically condensed gutta-percha technique. KEY LEARNING POINTS Good illumination and magnification are vital during root canal treatment. Crown-down preparation using the balanced force technique with flexible files makes instrumentation easier and prevents many of the procedural errors that can occur with filing techniques. Greater Taper instruments made of nickel-titanium are sufficiently flexible to be used in complex curved canals and obviate the need for step-back flaring of the apical preparation. Vertical compaction of warm gutta-percha may simplify the obturation of complex root canal systems. When the technical difficulty of a procedure exceeds the expertise of the practitioner, specialist referral may be required.
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Affiliation(s)
- J S Rhodes
- Department of Conservative Dentistry, GKT Dental Institute, Guy's Hospital, London, UK.
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Rhodes JS, Hosack GR, Girard I, Kelley AE, Mitchell GS, Garland T. Differential sensitivity to acute administration of cocaine, GBR 12909, and fluoxetine in mice selectively bred for hyperactive wheel-running behavior. Psychopharmacology (Berl) 2001; 158:120-31. [PMID: 11702085 DOI: 10.1007/s002130100857] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2000] [Accepted: 06/05/2001] [Indexed: 11/28/2022]
Abstract
RATIONALE To study the neural basis of genetic hyperactivity, we measured acute drug responses of mice (Mus domesticus) from four replicate lines that had been selectively bred (23-24 generations) for increased running-wheel activity. OBJECTIVES We tested the hypothesis that the high-running lines would respond differently to cocaine, GBR 12909, and fluoxetine (Prozac) compared with four replicate, random-bred, control lines. We also tested the hypothesis that the high-running lines would display hyperactivity in cages without wheels. METHODS Drug trials were conducted at night, during peak activity, after animals were habituated (3 weeks) to their cages with attached wheels. Revolutions on wheels 10-40 min post-injection were used to quantify drug responses. In a separate study, total photobeam breaks (produced on the first and second 24-h period of exposure) were used to quantify basal activity in animals deprived of wheels. RESULTS Cocaine and GBR 12909 decreased wheel running in selected lines by reducing the average speed but not the duration of running, but these drugs had little effect in control lines. Fluoxetine reduced running speed and duration in both selected and control animals, and the magnitude of the reduction was proportional to baseline activity. Basal activity in animals deprived of wheels (quantified using photobeam breaks) was significantly higher in selected than control lines on the second day of testing. CONCLUSIONS These results suggest an association between genetically determined hyperactive wheel-running behavior and dysfunction in the dopaminergic neuromodulatory system. Our selected lines may prove to be a useful genetic model for attention deficit hyperactivity disorder.
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Affiliation(s)
- J S Rhodes
- Department of Zoology, University of Wisconsin, 430 Lincoln Drive, Madison, WI 53706, USA.
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Dumke CL, Rhodes JS, Garland T, Maslowski E, Swallow JG, Wetter AC, Cartee GD. Genetic selection of mice for high voluntary wheel running: effect on skeletal muscle glucose uptake. J Appl Physiol (1985) 2001; 91:1289-97. [PMID: 11509528 DOI: 10.1152/jappl.2001.91.3.1289] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Effects of genetic selection for high wheel-running activity (17th generation) and access to running wheels on skeletal muscle glucose uptake were studied in mice with the following treatments for 8 wk: 1) access to unlocked wheels; 2) same as 1, but wheels locked 48 h before glucose uptake measurement; or 3) wheels always locked. Selected mice ran more than random-bred (nonselected) mice (8-wk mean +/- SE = 8,243 +/- 711 vs. 3,719 +/- 233 revolutions/day). Body weight was 5-13% lower for selected vs. nonselected groups. Fat pad/body weight was ~40% lower for selected vs. nonselected and unlocked vs. locked groups. Insulin-stimulated glucose uptake and fat pad/body weight were inversely correlated for isolated soleus (r = -0.333; P < 0.005) but not extensor digitorum longus (EDL) or epitrochlearis muscles. Insulin-stimulated glucose uptake was higher in EDL (P < 0.02) for selected vs. nonselected mice. Glucose uptake did not differ by wheel group, and amount of running did not correlate with glucose uptake for any muscle. Wheel running by mice did not enhance subsequent glucose uptake by isolated muscles.
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Affiliation(s)
- C L Dumke
- Biodynamics Laboratory and Department of Kinesiology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Abstract
AIM The purpose of this study was to compare the efficacy in vitro of gutta-percha removal from obturated root canals using ProFiles. METHODOLOGY Forty-eight human root canals with curvatures ranging between 25 and 45 degrees were instrumented by a standardized method to an apical ISO size 30 and 0.04 taper. They were obturated with vertically condensed gutta-percha. Retreatment was performed with the following techniques: K-Flexofiles with chloroform; Hedstrom files with chloroform; ProFiles 0.04 taper with chloroform; ProFiles 0.04 taper alone. The time for each method was measured. A microfocal macroradiographic technique was used to evaluate the amount of debris remaining within the root canals after the retreatment procedure. Roots were divided into apical, middle and coronal parts and scored on a scale of 0 (no debris) to 3 (> 50% of walls covered with debris) by trained observers on two separate occasions. RESULTS The scores for debris remaining within root canals for K-Flexofiles with chloroform and ProFiles with chloroform were the lowest and not significantly different at all three levels of the roots examined (P > 0.05), and Hedstrom files with chloroform and ProFiles with chloroform were not significantly different in the apical part. In general, coronal parts were cleaner than apical parts. The difference in scores at the three levels between ProFiles with chloroform and ProFiles alone were each significant (P < 0.01). Instrumentation using ProFiles with chloroform (mean 6.42 min) was significantly faster than using hand files (mean 11.67 min) (P < 0.01). CONCLUSION The results indicated that ProFiles or hand files with chloroform produced similarly clean canals, but that ProFiles were faster.
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Affiliation(s)
- J J Ferreira
- Department of Conservative Dentistry, Guy's, King's and St. Thomas' Dental Institute, Kings College, London, UK
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Bronikowski AM, Carter PA, Swallow JG, Girard IA, Rhodes JS, Garland T. Open-field behavior of house mice selectively bred for high voluntary wheel-running. Behav Genet 2001; 31:309-16. [PMID: 11699603 DOI: 10.1023/a:1012283426530] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Open-field behavioral assays are commonly used to test both locomotor activity and emotionality in rodents. We performed open-field tests on house mice (Mus domesticus) from four replicate lines genetically selected for high voluntary wheel-running for 22 generations and from four replicate random-bred control lines. Individual mice were recorded by video camera for 3 min in a 1-m2 open-field arena on 2 consecutive days. Mice from selected lines showed no statistical differences from control mice with respect to distance traveled, defecation, time spent in the interior, or average distance from the center of the arena during the trial. Thus, we found little evidence that open-field behavior, as traditionally defined, is genetically correlated with wheel-running behavior. This result is a useful converse test of classical studies that report no increased wheel-running in mice selected for increased open-field activity. However, mice from selected lines turned less in their travel paths than did control-line mice, and females from selected lines had slower travel times (longer latencies) to reach the wall. We discuss these results in the context of the historical open-field test and newly defined measures of open-field activity.
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Affiliation(s)
- A M Bronikowski
- Department of Zoology, University of Wisconsin, Madison 53706, USA.
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Abstract
AIM The aim of the study was to compare the shaping of root canals by two nickel-titanium instrumentation techniques using microcomputed tomography (MCT). METHODOLOGY Ten mandibular first molar teeth (30 canals) that had intact crowns and fully formed roots were scanned using MCT. Fifteen canals were instrumented using NiTiFlex hand files (Maillefer) using balanced force. The remainder were instrumented using prototype ProFile 0.04 Taper instruments (Dentsply) in a crown-down manner to an apical size ISO 25. The teeth were scanned again following instrumentation. The two instrumentation techniques were compared in a total of 27 canals. The area of dentine removed at predetermined levels (2.0, 3.0, 4.5, 6.0, 7.5 mm) from the apex was measured. Transportation and centring were recorded. Images constructed at these levels were compared with video images of equivalent physical sections created after the second scan. The volume of dentine removed in the apical 7.5 mm of the root canals of each tooth was calculated and the different techniques compared. Rendered three-dimensional images were used to assess the preparations qualitatively. The time taken for preparation was recorded. RESULTS There was no significant difference between hand instrumentation with NitiFlex files and machine instrumentation with prototype ProFile 0.04 Taper instruments for any of the variables tested. CONCLUSIONS Both techniques produced well centred and tapered preparations.
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Affiliation(s)
- J S Rhodes
- Department of Conservative Dentistry, GKT Dental Institute, Kings College, Guy's Hospital, London, UK
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Abstract
AIM Micro-computed tomography (MCT) using conebeam geometry is a method of producing true 3D images of the structure of small samples. A prototype MCT unit was adapted for imaging teeth to examine whether it could be used to quantify the instrumentation of root canals. METHODOLOGY Ten mandibular first molar teeth that had intact crowns and fully formed roots were scanned using MCT at a resolution of 0.081 mm and 3D-rendered images created; root canals were segmented from this. Reproducibility of MCT was verified for root canal shape and size. Access cavities were prepared into the pulp space and root canals enlarged to a continously tapering preparation using a crowndown technique. Each tooth was scanned again to allow comparison of pre- and post-instrumentation images. The roots were then sectioned at five predetermined horizontal levels for video-digitized measurement of dimensions of roots and root canals. The video images had a resolution of 0.025 mm. Video-digitized images of the physical cut surfaces were compared with equivalent MCT reconstructed images. The total area of the root canals (internal) and root (external) at each level were calculated from both MCT reconstructions and video-digitized images, and compared. RESULTS There was a highly significant correlation between MCT and video images for both external and internal areas (r = 0.94). Rendered 3D images were constructed to show the root canal systems of teeth. The total volumes of the apical 7.5 mm of root canals were calculated from rendered images of nine teeth before and after instrumentation. The mean amount of dentine removed by instrumentation was 3.725 mm3, which was 28% of the original canal volume. CONCLUSIONS Micro-computed tomography was shown to be accurate for experimental endodontology.
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Affiliation(s)
- J S Rhodes
- Department of Conservative Dentistry, GKT School of Dentistry, King's College, London, UK
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Rhodes JS. The Raleigh Academy of Medicine. N C Med J 1981; 42:263-264. [PMID: 7017427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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