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Horvat L, Foschini A, Grinias JP, Waterhouse BD, Devilbiss DM. Repetitive mild traumatic brain injury impairs norepinephrine system function and psychostimulant responsivity. Brain Res 2024; 1839:149040. [PMID: 38815643 DOI: 10.1016/j.brainres.2024.149040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/26/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024]
Abstract
Traumatic brain injury (TBI) is a complex pathophysiological process that results in a variety of neurotransmitter, behavioral, and cognitive deficits. The locus coeruleus-norepinephrine (LC-NE) system is a critical regulator of arousal levels and higher executive processes affected by TBI including attention, working memory, and decision making. LC-NE axon injury and impaired signaling within the prefrontal cortex (PFC) is a potential contributor to the neuropsychiatric symptoms after single, moderate to severe TBI. The majority of TBIs are mild, yet long-term cognitive deficits and increased susceptibility for further injury can accumulate after each repetitive mild TBI. As a potential treatment for restoring cognitive function and daytime sleepiness after injury psychostimulants, including methylphenidate (MPH) that increase levels of NE within the PFC, are being prescribed "off-label". The impact of mild and repetitive mild TBI on the LC-NE system remains limited. Therefore, we determined the extent of LC-NE and arousal dysfunction and response to therapeutic doses of MPH in rats following experimentally induced single and repetitive mild TBI. Microdialysis measures of basal NE efflux from the medial PFC and arousal measures were significantly lower after repetitive mild TBI. Females showed higher baseline PFC-NE efflux than males following single and repetitive mild TBI. In response to MPH challenge, males exhibited a blunted PFC-NE response and persistent arousal levels following repetitive mild TBI. These results provide critical insight into the role of catecholamine system dysfunction associated with cognitive deficits following repeated injury, outcome differences between sex/gender, and lack of success of MPH as an adjunctive therapy to improve cognitive function following injury.
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Affiliation(s)
- Leah Horvat
- Rowan University, Department of Chemistry and Biochemistry, Science Hall 301G, 230 Meditation Walk, Glassboro, NJ 08028, USA
| | - Alexis Foschini
- Rowan University, Department of Cell Biology and Neuroscience, Science Center 220, 2 Medical Center Drive, Stratford, NJ, 08084, USA
| | - James P Grinias
- Rowan University, Department of Chemistry and Biochemistry, Science Hall 301G, 230 Meditation Walk, Glassboro, NJ 08028, USA
| | - Barry D Waterhouse
- Rowan University, Department of Cell Biology and Neuroscience, Science Center 220, 2 Medical Center Drive, Stratford, NJ, 08084, USA
| | - David M Devilbiss
- Rowan University, Department of Cell Biology and Neuroscience, Science Center 220, 2 Medical Center Drive, Stratford, NJ, 08084, USA.
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2
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Robbins EM, Jaquins-Gerstl AS, Okonkwo DO, Boutelle MG, Michael AC. Dexamethasone-Enhanced Continuous Online Microdialysis for Neuromonitoring of O 2 after Brain Injury. ACS Chem Neurosci 2023. [PMID: 37369003 PMCID: PMC10360069 DOI: 10.1021/acschemneuro.2c00703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023] Open
Abstract
Traumatic brain injury (TBI) is a major public health crisis in many regions of the world. Severe TBI may cause a primary brain lesion with a surrounding penumbra of tissue that is vulnerable to secondary injury. Secondary injury presents as progressive expansion of the lesion, possibly leading to severe disability, a persistent vegetive state, or death. Real time neuromonitoring to detect and monitor secondary injury is urgently needed. Dexamethasone-enhanced continuous online microdialysis (Dex-enhanced coMD) is an emerging paradigm for chronic neuromonitoring after brain injury. The present study employed Dex-enhanced coMD to monitor brain K+ and O2 during manually induced spreading depolarization in the cortex of anesthetized rats and after controlled cortical impact, a widely used rodent model of TBI, in behaving rats. Consistent with prior reports on glucose, O2 exhibited a variety of responses to spreading depolarization and a prolonged, essentially permanent decline in the days after controlled cortical impact. These findings confirm that Dex-enhanced coMD delivers valuable information regarding the impact of spreading depolarization and controlled cortical impact on O2 levels in the rat cortex.
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Affiliation(s)
- Elaine M Robbins
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Andrea S Jaquins-Gerstl
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - David O Okonkwo
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, United States
| | - Martyn G Boutelle
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Adrian C Michael
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
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3
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King H, Reiber M, Philippi V, Stirling H, Aulehner K, Bankstahl M, Bleich A, Buchecker V, Glasenapp A, Jirkof P, Miljanovic N, Schönhoff K, von Schumann L, Leenaars C, Potschka H. Anesthesia and analgesia for experimental craniotomy in mice and rats: a systematic scoping review comparing the years 2009 and 2019. Front Neurosci 2023; 17:1143109. [PMID: 37207181 PMCID: PMC10188949 DOI: 10.3389/fnins.2023.1143109] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/27/2023] [Indexed: 05/21/2023] Open
Abstract
Experimental craniotomies are a common surgical procedure in neuroscience. Because inadequate analgesia appears to be a problem in animal-based research, we conducted this review and collected information on management of craniotomy-associated pain in laboratory mice and rats. A comprehensive search and screening resulted in the identification of 2235 studies, published in 2009 and 2019, describing craniotomy in mice and/or rats. While key features were extracted from all studies, detailed information was extracted from a random subset of 100 studies/year. Reporting of perioperative analgesia increased from 2009 to 2019. However, the majority of studies from both years did not report pharmacologic pain management. Moreover, reporting of multimodal treatments remained at a low level, and monotherapeutic approaches were more common. Among drug groups, reporting of pre- and postoperative administration of non-steroidal anti-inflammatory drugs, opioids, and local anesthetics in 2019 exceeded that of 2009. In summary, these results suggest that inadequate analgesia and oligoanalgesia are persistent issues associated with experimental intracranial surgery. This underscores the need for intensified training of those working with laboratory rodents subjected to craniotomies. Systematic review registration https://osf.io/7d4qe.
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Affiliation(s)
- Hannah King
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Maria Reiber
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Vanessa Philippi
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Helen Stirling
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Katharina Aulehner
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Marion Bankstahl
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - André Bleich
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - Verena Buchecker
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Aylina Glasenapp
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - Paulin Jirkof
- Office for Animal Welfare and 3Rs, University of Zurich, Zurich, Switzerland
| | - Nina Miljanovic
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Katharina Schönhoff
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Lara von Schumann
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Cathalijn Leenaars
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
- *Correspondence: Heidrun Potschka,
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4
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Dobryakova E, Zuckerman S, Sandry J. Neural correlates of extrinsic and intrinsic outcome processing during learning in individuals with TBI: a pilot investigation. Brain Imaging Behav 2021; 16:344-354. [PMID: 34406636 DOI: 10.1007/s11682-021-00508-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2021] [Indexed: 10/20/2022]
Abstract
Outcome processing, the ability to learn from feedback, is an important component of adaptive behavior and rehabilitation. Evidence from healthy adults implicates the striatum and dopamine in outcome processing. Animal research shows that damage to dopaminergic pathways in the brain can lead to a disruption of dopamine tone and transmission. Such evidence thus suggests that persons with TBI experience deficits in outcome processing. However, no research has directly investigated outcome processing and associated neural mechanisms in TBI. Here, we examine outcome processing in individuals with TBI during learning. Given that TBI negatively impacts striatal and dopaminergic systems, we hypothesize that individuals with TBI exhibit deficits in learning from outcomes. To test this hypothesis, individuals with moderate-to-severe TBI and healthy adults were presented with a declarative paired-associate word learning task. Outcomes indicating performance accuracy were presented immediately during task performance and in the form of either monetary or performance-based feedback. Two types of feedback provided the opportunity to test whether extrinsic and intrinsic motivational aspects of outcome presentation play a role during learning and outcome processing. Our results show that individuals with TBI exhibited impaired learning from feedback compared to healthy participants. Additionally, individuals with TBI exhibited increased activation in the striatum during outcome processing. The results of this study suggest that outcome processing and learning from immediate outcomes is impaired in individuals with TBI and might be related to inefficient use of neural resources during task performance as reflected by increased activation of the striatum.
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Affiliation(s)
- Ekaterina Dobryakova
- Center for Traumatic Brain Injury Research, Kessler Foundation, 120 Eagle Rock Ave., East Hanover, NJ, 07936, USA. .,Department of Physical Medicine and Rehabilitation, Rutgers-New Jersey Medical School, Newark, NJ, USA.
| | - Suzanne Zuckerman
- Center for Traumatic Brain Injury Research, Kessler Foundation, 120 Eagle Rock Ave., East Hanover, NJ, 07936, USA
| | - Joshua Sandry
- Psychology Department, Montclair State University, 1 Normal Ave., Montclair, NJ, USA
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5
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Reward presentation reduces on-task fatigue in traumatic brain injury. Cortex 2020; 126:16-25. [PMID: 32062140 DOI: 10.1016/j.cortex.2020.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/10/2019] [Accepted: 01/07/2020] [Indexed: 11/22/2022]
Abstract
While cognitive fatigue is experienced by up to 80% of individuals with traumatic brain injury (TBI), little is known about its neural underpinnings. We previously hypothesized that presentation of rewarding outcomes leads to cognitive fatigue reduction and activation of the striatum, a brain region shown to be associated with cognitive fatigue in clinical populations and processing of rewarding outcomes. We have demonstrated this in individuals with multiple sclerosis. Here, we tested this hypothesis in individuals with TBI. Twenty-one individuals with TBI and 24 healthy participants underwent functional magnetic resonance imaging. Participants performed a task during which they were presented with 1) the Outcome condition where they were exposed to monetary rewards, and 2) the No Outcome condition that served as the control condition and was not associated with monetary rewards. In accordance with our hypothesis, results showed that attainment of rewarding outcomes leads to cognitive fatigue reduction in individuals with TBI, as well as activation of the striatum. Specifically, we observed a significant group by condition interaction on fatigue scores driven by the TBI group reporting lower levels of fatigue after the Outcome condition. fMRI data revealed a significant main-effect of condition in regions previously implicated in outcome processing, while a significant group by condition interaction was observed in the left ventral striatum as revealed by a priori region of interest analysis. Results suggest that a salient motivator can significantly reduce fatigue and that outcome presentation leads to increased activation of the ventral striatum in TBI. These findings can inform the development of future non-pharmacological cognitive fatigue treatment methods and contribute to the growing body of evidence showing the association between cognitive fatigue and the striatum.
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6
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Executive (dys)function after traumatic brain injury: special considerations for behavioral pharmacology. Behav Pharmacol 2019; 29:617-637. [PMID: 30215621 PMCID: PMC6155367 DOI: 10.1097/fbp.0000000000000430] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Executive function is an umbrella term that includes cognitive processes such as decision-making, impulse control, attention, behavioral flexibility, and working memory. Each of these processes depends largely upon monoaminergic (dopaminergic, serotonergic, and noradrenergic) neurotransmission in the frontal cortex, striatum, and hippocampus, among other brain areas. Traumatic brain injury (TBI) induces disruptions in monoaminergic signaling along several steps in the neurotransmission process - synthesis, distribution, and breakdown - and in turn, produces long-lasting deficits in several executive function domains. Understanding how TBI alters monoamingeric neurotransmission and executive function will advance basic knowledge of the underlying principles that govern executive function and potentially further treatment of cognitive deficits following such injury. In this review, we examine the influence of TBI on the following measures of executive function - impulsivity, behavioral flexibility, and working memory. We also describe monoaminergic-systems changes following TBI. Given that TBI patients experience alterations in monoaminergic signaling following injury, they may represent a unique population with regard to pharmacotherapy. We conclude this review by discussing some considerations for pharmacotherapy in the field of TBI.
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7
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8
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Wylie GR, Dobryakova E, DeLuca J, Chiaravalloti N, Essad K, Genova H. Cognitive fatigue in individuals with traumatic brain injury is associated with caudate activation. Sci Rep 2017; 7:8973. [PMID: 28827779 PMCID: PMC5567054 DOI: 10.1038/s41598-017-08846-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 07/18/2017] [Indexed: 01/09/2023] Open
Abstract
We investigated differences in brain activation associated with cognitive fatigue between persons with traumatic brain injury (TBI) and healthy controls (HCs). Twenty-two participants with moderate-severe TBI and 20 HCs performed four blocks of a difficult working memory task and four blocks of a control task during fMRI imaging. Cognitive fatigue, assessed before and after each block, was used as a covariate to assess fatigue-related brain activation. The TBI group reported more fatigue than the HCs, though their performance was comparable. Regarding brain activation, the TBI group showed a Task X Fatigue interaction in the caudate tail resulting from a positive correlation between fatigue and brain activation for the difficult task and a negative relationship for the control task. The HC group showed the same Task X Fatigue interaction in the caudate head. Because we had prior hypotheses about the caudate, we performed a confirmatory analysis of a separate dataset in which the same subjects performed a processing speed task. A relationship between Fatigue and brain activation was evident in the caudate for this task as well. These results underscore the importance of the caudate nucleus in relation to cognitive fatigue.
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Affiliation(s)
- G R Wylie
- Kessler Foundation, 120 Eagle Rock Avenue, Suite 100, East Hanover, New Jersey, 07936, USA. .,Department of Physical Medicine and Rehabilitation, Rutgers University, New Jersey Medical School, Newark, NJ, 07101, USA. .,The War Related Illness and Injury Study Center, The Department of Veterans' Affairs, New Jersey Healthcare System, East Orange Campus, East Orange, NJ, 07018, USA.
| | - E Dobryakova
- Kessler Foundation, 120 Eagle Rock Avenue, Suite 100, East Hanover, New Jersey, 07936, USA.,Department of Physical Medicine and Rehabilitation, Rutgers University, New Jersey Medical School, Newark, NJ, 07101, USA
| | - J DeLuca
- Kessler Foundation, 120 Eagle Rock Avenue, Suite 100, East Hanover, New Jersey, 07936, USA.,Department of Physical Medicine and Rehabilitation, Rutgers University, New Jersey Medical School, Newark, NJ, 07101, USA.,Department of Neurology, Rutgers University, New Jersey Medical School, Newark, NJ, 07101, USA
| | - N Chiaravalloti
- Kessler Foundation, 120 Eagle Rock Avenue, Suite 100, East Hanover, New Jersey, 07936, USA.,Department of Physical Medicine and Rehabilitation, Rutgers University, New Jersey Medical School, Newark, NJ, 07101, USA
| | - K Essad
- Dartmouth College, Dartmouth College Medical School, Hanover, NH, 03755, USA
| | - H Genova
- Kessler Foundation, 120 Eagle Rock Avenue, Suite 100, East Hanover, New Jersey, 07936, USA.,Department of Physical Medicine and Rehabilitation, Rutgers University, New Jersey Medical School, Newark, NJ, 07101, USA
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9
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Harun R, Grassi CM, Munoz MJ, Wagner AK. Modeling Fast-scan Cyclic Voltammetry Data from Electrically Stimulated Dopamine Neurotransmission Data Using QNsim1.0. J Vis Exp 2017. [PMID: 28605373 DOI: 10.3791/55595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Central dopaminergic (DAergic) pathways have an important role in a wide range of functions, such as attention, motivation, and movement. Dopamine (DA) is implicated in diseases and disorders including attention deficit hyperactivity disorder, Parkinson's disease, and traumatic brain injury. Thus, DA neurotransmission and the methods to study it are of intense scientific interest. In vivo fast-scan cyclic voltammetry (FSCV) is a method that allows for selectively monitoring DA concentration changes with fine temporal and spatial resolution. This technique is commonly used in conjunction with electrical stimulations of ascending DAergic pathways to control the impulse flow of dopamine neurotransmission. Although the stimulated DA neurotransmission paradigm can produce robust DA responses with clear morphologies, making them amenable for kinetic analysis, there is still much debate on how to interpret the responses in terms of their DA release and clearance components. To address this concern, a quantitative neurobiological (QN) framework of stimulated DA neurotransmission was recently developed to realistically model the dynamics of DA release and reuptake over the course of a stimulated DA response. The foundations of this model are based on experimental data from stimulated DA neurotransmission and on principles of neurotransmission adopted from various lines of research. The QN model implements 12 parameters related to stimulated DA release and reuptake dynamics to model DA responses. This work describes how to simulate DA responses using QNsim1.0 and also details principles that have been implemented to systematically discern alterations in the stimulated dopamine release and reuptake dynamics.
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Affiliation(s)
- Rashed Harun
- Center for Neuroscience, University of Pittsburgh; Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine; Safar Center for Resuscitation Research, University of Pittsburgh;
| | - Christine M Grassi
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine
| | - Miranda J Munoz
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine; Department of Biological Sciences, Mellon College of Science, Carnegie Mellon University
| | - Amy K Wagner
- Center for Neuroscience, University of Pittsburgh; Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine; Safar Center for Resuscitation Research, University of Pittsburgh
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10
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Nora GJ, Harun R, Fine DF, Hutchison D, Grobart AC, Stezoski JP, Munoz MJ, Kochanek PM, Leak RK, Drabek T, Wagner AK. Ventricular fibrillation cardiac arrest produces a chronic striatal hyperdopaminergic state that is worsened by methylphenidate treatment. J Neurochem 2017; 142:305-322. [PMID: 28445595 DOI: 10.1111/jnc.14058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 04/19/2017] [Accepted: 04/20/2017] [Indexed: 01/21/2023]
Abstract
Cardiac arrest survival rates have improved with modern resuscitation techniques, but many survivors experience impairments associated with hypoxic-ischemic brain injury (HIBI). Currently, little is understood about chronic changes in striatal dopamine (DA) systems after HIBI. Given the common empiric clinical use of DA enhancing agents in neurorehabilitation, investigation evaluating dopaminergic alterations after cardiac arrest (CA) is necessary to optimize rehabilitation approaches. We hypothesized that striatal DA neurotransmission would be altered chronically after ventricular fibrillation cardiac arrest (VF-CA). Fast-scan cyclic voltammetry was used with median forebrain bundle (MFB) maximal electrical stimulations (60Hz, 10s) in rats to characterize presynaptic components of DA neurotransmission in the dorsal striatum (D-Str) and nucleus accumbens 14 days after a 5-min VF-CA when compared to Sham or Naïve. VF-CA increased D-Str-evoked overflow [DA], total [DA] released, and initial DA release rate versus controls, despite also increasing maximal velocity of DA reuptake (Vmax ). Methylphenidate (10 mg/kg), a DA transporter inhibitor, was administered to VF-CA and Shams after establishing a baseline, pre-drug 60 Hz, 5 s stimulation response. Methylphenidate increased initial evoked overflow [DA] more-so in VF-CA versus Sham and reduced D-Str Vmax in VF-CA but not Shams; these findings are consistent with upregulated striatal DA transporter in VF-CA versus Sham. Our work demonstrates that 5-min VF-CA increases electrically stimulated DA release with concomitant upregulation of DA reuptake 2 weeks after brief VF-CA insult. Future work should elucidate how CA insult duration, time after insult, and insult type influence striatal DA neurotransmission and related cognitive and motor functions.
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Affiliation(s)
- Gerald J Nora
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rashed Harun
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - David F Fine
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Daniel Hutchison
- Mylan School of Pharmacy, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Adam C Grobart
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jason P Stezoski
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Miranda J Munoz
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Patrick M Kochanek
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rehana K Leak
- Mylan School of Pharmacy, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Tomas Drabek
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Amy K Wagner
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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11
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Jenkins PO, Mehta MA, Sharp DJ. Catecholamines and cognition after traumatic brain injury. Brain 2016; 139:2345-71. [PMID: 27256296 PMCID: PMC4995357 DOI: 10.1093/brain/aww128] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/20/2016] [Indexed: 01/11/2023] Open
Abstract
Cognitive problems are one of the main causes of ongoing disability after traumatic brain injury. The heterogeneity of the injuries sustained and the variability of the resulting cognitive deficits makes treating these problems difficult. Identifying the underlying pathology allows a targeted treatment approach aimed at cognitive enhancement. For example, damage to neuromodulatory neurotransmitter systems is common after traumatic brain injury and is an important cause of cognitive impairment. Here, we discuss the evidence implicating disruption of the catecholamines (dopamine and noradrenaline) and review the efficacy of catecholaminergic drugs in treating post-traumatic brain injury cognitive impairments. The response to these therapies is often variable, a likely consequence of the heterogeneous patterns of injury as well as a non-linear relationship between catecholamine levels and cognitive functions. This individual variability means that measuring the structure and function of a person’s catecholaminergic systems is likely to allow more refined therapy. Advanced structural and molecular imaging techniques offer the potential to identify disruption to the catecholaminergic systems and to provide a direct measure of catecholamine levels. In addition, measures of structural and functional connectivity can be used to identify common patterns of injury and to measure the functioning of brain ‘networks’ that are important for normal cognitive functioning. As the catecholamine systems modulate these cognitive networks, these measures could potentially be used to stratify treatment selection and monitor response to treatment in a more sophisticated manner.
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Affiliation(s)
- Peter O Jenkins
- 1 The Division of Brain Sciences, The Department of Medicine, Imperial College London, UK
| | - Mitul A Mehta
- 2 Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK
| | - David J Sharp
- 1 The Division of Brain Sciences, The Department of Medicine, Imperial College London, UK
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12
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Myrga JM, Juengst SB, Failla MD, Conley YP, Arenth PM, Grace AA, Wagner AK. COMT and ANKK1 Genetics Interact With Depression to Influence Behavior Following Severe TBI: An Initial Assessment. Neurorehabil Neural Repair 2016; 30:920-930. [PMID: 27154305 DOI: 10.1177/1545968316648409] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Genetic variations in the dopamine (DA) system are associated with cortical-striatal behavior in multiple populations. This study assessed associations of functional polymorphisms in the ankyrin repeat and kinase domain (ANKK1; Taq1a) and catechol-O-methyltransferase (COMT; Val158Met) genes with behavioral dysfunction following traumatic brain injury (TBI). PARTICIPANTS This was a prospective study of 90 survivors of severe TBI recruited from a level 1 trauma center. MAIN MEASURES The Frontal Systems Behavior Scale, a self- or family report questionnaire evaluating behavior associated with frontal lobe dysfunction, was completed 6 and 12 months postinjury. Depression was measured concurrently with the Patient Health Questionnaire-9. Study participants were genotyped for Val158Met and Taq1a polymorphisms. RESULTS No statistically significant behavioral differences were observed by Taq1a or Val158Met genotype alone. At 12 months, among those with depression, Met homozygotes (Val158Met) self-reported worse behavior than Val carriers (P = .015), and A2 homozygotes (Taq1a) self-reported worse behavior than A1 carriers (P = .028) in bivariable analysis. Multivariable models suggest an interaction between depression and genetic variation with behavior at 12 months post-TBI, and descriptive analysis suggests that carriage of both risk alleles may contribute to worse behavioral performance than carriage of either risk allele alone. CONCLUSION In the context of depression, Val158Met and Taq1a polymorphisms are individually associated with behavioral dysfunction 12 months following severe TBI, with preliminary evidence suggesting cumulative, or perhaps epistatic, effects of COMT and ANKK1 on behavioral dysfunction.
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Affiliation(s)
- John M Myrga
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, PA
| | - Shannon B Juengst
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, PA
| | | | - Yvette P Conley
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, PA
| | - Patricia M Arenth
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, PA
| | - Anthony A Grace
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, PA
| | - Amy K Wagner
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, PA Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA Department of Neuroscience, University of Pittsburgh, Pittsburgh PA Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA
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13
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Harun R, Hare KM, Brough EM, Munoz MJ, Grassi CM, Torres GE, Grace AA, Wagner AK. Fast-scan cyclic voltammetry demonstrates that L-DOPA produces dose-dependent, regionally selective bimodal effects on striatal dopamine kinetics in vivo. J Neurochem 2016; 136:1270-1283. [PMID: 26611352 PMCID: PMC4884169 DOI: 10.1111/jnc.13444] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 11/29/2022]
Abstract
Parkinson's disease (PD) is a debilitating condition that is caused by a relatively specific degeneration of dopaminergic (DAergic) neurons of the substantia nigra pars compacta. L-DOPA was introduced as a viable treatment option for PD over 40 years ago and still remains the most common and effective therapy for PD. Though the effects of L-DOPA to augment striatal DA production are well known, little is actually known about how L-DOPA alters the kinetics of DA neurotransmission that contribute to its beneficial and adverse effects. In this study, we examined the effects of L-DOPA administration (50 mg/kg carbidopa + 0, 100, and 250 mg/kg L-DOPA) on regional electrically stimulated DA response kinetics using fast-scan cyclic voltammetry in anesthetized rats. We demonstrate that L-DOPA enhances DA release in both the dorsal striatum (D-STR) and nucleus accumbens (NAc), but surprisingly causes a delayed inhibition of release in the D-STR. In both regions, L-DOPA progressively attenuated reuptake kinetics, predominantly through a decrease in Vmax . These findings have important implications on understanding the pharmacodynamics of L-DOPA, which may be informative for understanding its therapeutic effects and also common side effects like L-DOPA-induced dyskinesias (LID). L-DOPA is commonly used to treat Parkinsonian symptoms, but little is known about how it affects presynaptic DA neurotransmission. Using in vivo fast-scan cyclic voltammetry, we show L-DOPA inhibits DA reuptake in a region-specific and dose-dependent manner, and L-DOPA has paradoxical effects on release. These findings may be important when considering mechanisms for L-DOPA's therapeutic benefits and adverse side-effects.
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Affiliation(s)
- Rashed Harun
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Safar Center for Resuscitation Research, Pittsburgh, Pennsylvania, USA
| | - Kristin M Hare
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Elizabeth M Brough
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Safar Center for Resuscitation Research, Pittsburgh, Pennsylvania, USA
| | - Miranda J Munoz
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Biological Sciences, Carnegie Mellon University, Mellon College of Science, Pittsburgh, Pennsylvania, USA
| | - Christine M Grassi
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Gonzalo E Torres
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Neurobiology, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Anthony A Grace
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Departments of Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Amy K Wagner
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Safar Center for Resuscitation Research, Pittsburgh, Pennsylvania, USA
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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14
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Neurobiological model of stimulated dopamine neurotransmission to interpret fast-scan cyclic voltammetry data. Brain Res 2014; 1599:67-84. [PMID: 25527399 DOI: 10.1016/j.brainres.2014.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 12/05/2014] [Accepted: 12/06/2014] [Indexed: 11/22/2022]
Abstract
Fast-scan cyclic voltammetry (FSCV) is an electrochemical method that can assess real-time in vivo dopamine (DA) concentration changes to study the kinetics of DA neurotransmission. Electrical stimulation of dopaminergic (DAergic) pathways can elicit FSCV DA responses that largely reflect a balance of DA release and reuptake. Interpretation of these evoked DA responses requires a framework to discern the contribution of DA release and reuptake. The current, widely implemented interpretive framework for doing so is the Michaelis-Menten (M-M) model, which is grounded on two assumptions- (1) DA release rate is constant during stimulation, and (2) DA reuptake occurs through dopamine transporters (DAT) in a manner consistent with M-M enzyme kinetics. Though the M-M model can simulate evoked DA responses that rise convexly, response types that predominate in the ventral striatum, the M-M model cannot simulate dorsal striatal responses that rise concavely. Based on current neurotransmission principles and experimental FSCV data, we developed a novel, quantitative, neurobiological framework to interpret DA responses that assumes DA release decreases exponentially during stimulation and continues post-stimulation at a diminishing rate. Our model also incorporates dynamic M-M kinetics to describe DA reuptake as a process of decreasing reuptake efficiency. We demonstrate that this quantitative, neurobiological model is an extension of the traditional M-M model that can simulate heterogeneous regional DA responses following manipulation of stimulation duration, frequency, and DA pharmacology. The proposed model can advance our interpretive framework for future in vivo FSCV studies examining regional DA kinetics and their alteration by disease and DA pharmacology.
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15
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Diaz-Arrastia R, Kochanek PM, Bergold P, Kenney K, Marx CE, Grimes CJB, Loh LTCY, Adam LTCGE, Oskvig D, Curley KC, Salzer W. Pharmacotherapy of traumatic brain injury: state of the science and the road forward: report of the Department of Defense Neurotrauma Pharmacology Workgroup. J Neurotrauma 2014; 31:135-58. [PMID: 23968241 DOI: 10.1089/neu.2013.3019] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Despite substantial investments by government, philanthropic, and commercial sources over the past several decades, traumatic brain injury (TBI) remains an unmet medical need and a major source of disability and mortality in both developed and developing societies. The U.S. Department of Defense neurotrauma research portfolio contains more than 500 research projects funded at more than $700 million and is aimed at developing interventions that mitigate the effects of trauma to the nervous system and lead to improved quality of life outcomes. A key area of this portfolio focuses on the need for effective pharmacological approaches for treating patients with TBI and its associated symptoms. The Neurotrauma Pharmacology Workgroup was established by the U.S. Army Medical Research and Materiel Command (USAMRMC) with the overarching goal of providing a strategic research plan for developing pharmacological treatments that improve clinical outcomes after TBI. To inform this plan, the Workgroup (a) assessed the current state of the science and ongoing research and (b) identified research gaps to inform future development of research priorities for the neurotrauma research portfolio. The Workgroup identified the six most critical research priority areas in the field of pharmacological treatment for persons with TBI. The priority areas represent parallel efforts needed to advance clinical care; each requires independent effort and sufficient investment. These priority areas will help the USAMRMC and other funding agencies strategically guide their research portfolios to ensure the development of effective pharmacological approaches for treating patients with TBI.
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Affiliation(s)
- Ramon Diaz-Arrastia
- 1 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
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16
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Brayer SW, Ketcham S, Zou H, Hurwitz M, Henderson C, Fuletra J, Kumar K, Skidmore E, Thiels E, Wagner AK. Developing a clinically relevant model of cognitive training after experimental traumatic brain injury. Neurorehabil Neural Repair 2014; 29:483-95. [PMID: 25239938 DOI: 10.1177/1545968314550367] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Following traumatic brain injury (TBI), clinical cognitive training paradigms harness implicit and explicit learning and memory systems to improve function; however, these systems are differentially affected by TBI, highlighting the need for an experimental TBI model that can test efficacy of cognitive training approaches. OBJECTIVES To develop a clinically relevant experimental cognitive training model using the Morris water maze (MWM) wherein training on implicitly learned task components was provided to improve behavioral performance post-TBI. METHODS Eighty-one adult male rats were divided by injury status (controlled cortical impact [CCI]/Sham), non-spatial cognitive training (CogTrained/No-CogTrained), and extra-maze cues (Cued/Non-Cued) during MWM testing. Platform latencies, thigmotaxis, and search strategies were assessed during MWM trials. RESULTS Cognitive training was associated with improved platform latencies, reduced thigmotaxis, and more effective search strategy use for Sham and CCI rats. In the Cued and Non-Cued MWM paradigm, there were no differences between CCI/CogTrained and Sham/No-CogTrained groups. During novel testing conditions, CogTrained groups applied implicitly learned knowledge/skills; however, sham-cued CogTrained/rats better incorporated extramaze cues into their search strategy than the CCI-Cued group. Cognitive training had no effects on contusion size or hippocampal cell survival. CONCLUSIONS The results provide evidence that CCI-CogTrained rats that learned the nonspatial components of the MWM task applied these skills during multiple conditions of the place-learning task, thereby mitigating cognitive deficits typically associated with this injury model. The results show that a systematic application of clinically relevant constructs associated with cognitive training paradigms can be used with experimental TBI to affect place learning.
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Affiliation(s)
- Samuel W Brayer
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh
| | - Scott Ketcham
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh
| | - Huichao Zou
- Department of Physical Medicine and Rehabilitation, Safar Center for Resuscitation Research, University of Pittsburgh
| | - Max Hurwitz
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh
| | | | - Jay Fuletra
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh
| | - Krishma Kumar
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh
| | | | - Edda Thiels
- Department of Neurobiology, University of Pittsburgh
| | - Amy K Wagner
- Department of Physical Medicine and Rehabilitation, Safar Center for Resuscitation Research, University of Pittsburgh
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17
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Robinson JD, Howard CD, Pastuzyn ED, Byers DL, Keefe KA, Garris PA. Methamphetamine-induced neurotoxicity disrupts pharmacologically evoked dopamine transients in the dorsomedial and dorsolateral striatum. Neurotox Res 2014; 26:152-67. [PMID: 24562969 PMCID: PMC4071119 DOI: 10.1007/s12640-014-9459-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 01/10/2014] [Accepted: 02/04/2014] [Indexed: 11/30/2022]
Abstract
Phasic dopamine (DA) signaling, during which burst firing by DA neurons generates short-lived elevations in extracellular DA in terminal fields called DA transients, is implicated in reinforcement learning. Disrupted phasic DA signaling is proposed to link DA depletions and cognitive-behavioral impairment in methamphetamine (METH)-induced neurotoxicity. Here, we further investigated this disruption by assessing effects of METH pretreatment on DA transients elicited by a drug cocktail of raclopride, a D2 DA receptor antagonist, and nomifensine, an inhibitor of the dopamine transporter (DAT). One advantage of this approach is that pharmacological activation provides a large, high-quality data set of transients elicited by endogenous burst firing of DA neurons for analysis of regional differences and neurotoxicity. These pharmacologically evoked DA transients were measured in the dorsomedial (DM) and dorsolateral (DL) striatum of urethane-anesthetized rats by fast-scan cyclic voltammetry. Electrically evoked DA levels were also recorded to quantify DA release and uptake, and DAT binding was determined by means of autoradiography to index DA denervation. Pharmacologically evoked DA transients in intact animals exhibited a greater amplitude and frequency and shorter duration in the DM compared to the DL striatum, despite similar pre- and post-drug assessments of DA release and uptake in both sub-regions as determined from the electrically evoked DA signals. METH pretreatment reduced transient activity. The most prominent effect of METH pretreatment on transients across striatal sub-region was decreased amplitude, which mirrored decreased DAT binding and was accompanied by decreased DA release. Overall, these results identify marked intrastriatal differences in the activity of DA transients that appear independent of presynaptic mechanisms for DA release and uptake and further support disrupted phasic DA signaling mediated by decreased DA release in rats with METH-induced neurotoxicity.
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Affiliation(s)
- John D. Robinson
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | | | - Elissa D. Pastuzyn
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
| | - Diane L. Byers
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Kristen A. Keefe
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA
| | - Paul A. Garris
- School of Biological Sciences, Illinois State University, Normal, IL, USA
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18
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Biomarkers of cognitive dysfunction in traumatic brain injury. J Neural Transm (Vienna) 2013; 121:79-90. [DOI: 10.1007/s00702-013-1078-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/30/2013] [Indexed: 12/11/2022]
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19
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Shin SS, Bales JW, Yan HQ, Kline AE, Wagner AK, Lyons-Weiler J, Dixon CE. The effect of environmental enrichment on substantia nigra gene expression after traumatic brain injury in rats. J Neurotrauma 2013; 30:259-70. [PMID: 23094804 DOI: 10.1089/neu.2012.2462] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Experimental investigations into the effects of traumatic brain injury (TBI) have demonstrated significant alterations in dopaminergic systems. Dopaminergic fibers originating within the substantia nigra and ventral tegmental area (VTA) are important for reward learning, addiction, movement, and behavior. However, little is known about the effect of TBI on substantia nigra and VTA function. Environmental enrichment (EE) has been shown to improve functional outcome after TBI, and a number of studies suggest that it may exert some benefits via dopaminergic signaling. To better understand the role of dopamine in chronic TBI pathophysiology and the effect of EE, we examined the mRNA expression profile within the substantia nigra and VTA at 4 weeks post-injury. Specifically, three comparisons were made: 1) TBI versus sham, 2) sham+EE versus sham+standard (STD) housing, and 3) TBI+EE versus TBI+STD. There were differential expressions of 25, 4, and 40 genes in these comparisons, respectively. Chronic alterations in genes post-injury within the substantia nigra and VTA included genes important for cellular membrane homeostasis and transcription. EE-induced gene alterations after TBI included genes important for signal transduction, in particular calcium signaling pathways, membrane homeostasis, and metabolism. Elucidation of these alterations in gene expression within the substantia nigra and VTA provides new insights into chronic changes in dopamine signaling post-TBI, and the potential role of EE in TBI rehabilitation.
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Affiliation(s)
- Samuel S Shin
- Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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20
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Wagner AK, Zitelli KT. A Rehabilomics focused perspective on molecular mechanisms underlying neurological injury, complications, and recovery after severe TBI. ACTA ACUST UNITED AC 2012; 20:39-48. [PMID: 22444246 DOI: 10.1016/j.pathophys.2012.02.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The molecular mechanisms underlying TBI pathophysiology and recovery are both complex and varied. Further, the pathology underlying many of the clinical sequelae observed in this population evolve over the acute injury period and encompass the subacute and chronic phases of recovery, supporting the contemporary concept that TBI is a chronic disease rather than a static insult from which limited recovery occurs. TBI related complications can also span from acute care to the very chronic stages of recovery that occur years after the initial trauma. Despite ongoing neurodegeneration, the TBI recovery period is also characterized by a propensity for neuroplasticity and rewiring through multiple mechanisms. This review summarizes key elements of acute pathophysiology, how they link to structural damage and ongoing degeneration, and how this process coincides with a permissive neuroplastic environment. The pathophysiology of selected TBI related complications is also discussed. Each of these concepts is studied through the lens of Rehabilomics, wherein an emphasis is placed on biomarker studies characterizing these pathophysiological mechanisms, and biomarker profiles are assessed in relation to multi-modal outcomes and susceptibility to rehabilitation relevant complications. In reviewing these concepts, implications for future research and theranostic principles for patient care are presented.
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Affiliation(s)
- Amy K Wagner
- Department of Physical Medicine and Rehabilitation, United States; Safar Center for Resuscitation Research, United States; Center for Neuroscience University of Pittsburgh, United States.
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21
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Shin SS, Bray ER, Zhang CQ, Dixon CE. Traumatic brain injury reduces striatal tyrosine hydroxylase activity and potassium-evoked dopamine release in rats. Brain Res 2010; 1369:208-15. [PMID: 21047500 DOI: 10.1016/j.brainres.2010.10.096] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 10/21/2010] [Accepted: 10/26/2010] [Indexed: 11/28/2022]
Abstract
There is increasing evidence that traumatic brain injury (TBI) induces hypofunction of the striatal dopaminergic system, the mechanisms of which are unknown. In this study, we analyzed the activity of striatal tyrosine hydroxylase (TH) in rats at 1 day, 1 week, and 4 weeks after TBI using the controlled cortical impact model. There were no changes in the level of TH phosphorylated at serine 40 site (pser40TH) at 1 day or 4 weeks. At 1 week, injured animals showed decreased pser40TH to 73.9±7.3% (p≤0.05) of sham injured rats. The in vivo TH activity assay showed no significant difference between injured and sham rats at 1 day. However, there was a decreased activity in injured rats to 62.1±8.2% (p≤0.05) and 68.8±6.2% (p≤0.05) of sham injured rats at 1 and 4 weeks, respectively. Also, the activity of protein kinase A, which activates TH, decreased at 1 week (injured: 87.8±2.8%, sham: 100.0±4.2%, p≤0.05). To study the release activity of dopamine after injury, potassium (80 mM)-evoked dopamine release was measured by microdialysis in awake, freely moving rats. Dialysates were collected and analyzed by high-performance liquid chromatography. There were no significant differences in dopamine release at 1 day and 4 weeks between sham and injured groups. At 1 week, there was a significant decrease (injured: 0.067±0.015 μM, sham: 0.127±0.027 μM, p≤0.05). These results suggest that TBI-induced dopamine neurotransmission deficits are, at least in part, attributable to deficits in TH activity.
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Affiliation(s)
- Samuel S Shin
- Brain Trauma Research Center, Department of Neurosurgery, University of Pittsburgh, 3434 Fifth Ave, Suite 201, Pittsburgh, PA 15260, USA
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