Medical Neurobiology Commons^™

Gamma Motor Neurons Express Distinct Genetic Markers At Birth And Require Muscle Spindle-Derived Gdnf For Postnatal Survival, Neil A. Shneider, Meghan N. Brown, Courtney A. Smith, James Pickel, Francisco J. Alvarez

Neuroscience, Cell Biology & Physiology Faculty Publications

Background: Gamma motor neurons (γ-MNs) selectively innervate muscle spindle intrafusal fibers and regulate their sensitivity to stretch. They constitute a distinct subpopulation that differs in morphology, physiology and connectivity from α-MNs, which innervate extrafusal muscle fibers and exert force. The mechanisms that control the differentiation of functionally distinct fusimotor neurons are unknown. Progress on this question has been limited by the absence of molecular markers to specifically distinguish and manipulate γ-MNs. Recently, it was reported that early embryonic γ-MN precursors are dependent on GDNF. Using this knowledge we characterized genetic strategies to label developing γ-MNs based on GDNF receptor expression, …

Mitochondrial Mislocalization Underlies Abeta42-Induced Neuronal Dysfunction In A Drosophila Model Of Alzheimer's Disease., Kanae Iijima-Ando, Stephen A Hearn, Christopher Shenton, Anthony Gatt, Lijuan Zhao, Koichi Iijima

Department of Biochemistry and Molecular Biology Faculty Papers

The amyloid-beta 42 (Abeta42) is thought to play a central role in the pathogenesis of Alzheimer's disease (AD). However, the molecular mechanisms by which Abeta42 induces neuronal dysfunction and degeneration remain elusive. Mitochondrial dysfunctions are implicated in AD brains. Whether mitochondrial dysfunctions are merely a consequence of AD pathology, or are early seminal events in AD pathogenesis remains to be determined. Here, we show that Abeta42 induces mitochondrial mislocalization, which contributes to Abeta42-induced neuronal dysfunction in a transgenic Drosophila model. In the Abeta42 fly brain, mitochondria were reduced in axons and dendrites, and accumulated in the somata without severe mitochondrial …

Development Of A Mouse Monoclonal Antibody Cocktail For Post-Exposure Rabies Prophylaxis In Humans., Thomas Müller, Bernhard Dietzschold, Hildegund Ertl, Anthony R Fooks, Conrad Freuling, Christine Fehlner-Gardiner, Jeannette Kliemt, Francois X Meslin, Charles E Rupprecht, Noël Tordo, Alexander I Wanderler, Marie Paule Kieny

Department of Microbiology and Immunology Faculty Papers

As the demand for rabies post-exposure prophylaxis (PEP) treatments has increased exponentially in recent years, the limited supply of human and equine rabies immunoglobulin (HRIG and ERIG) has failed to provide the required passive immune component in PEP in countries where canine rabies is endemic. Replacement of HRIG and ERIG with a potentially cheaper and efficacious alternative biological for treatment of rabies in humans, therefore, remains a high priority. In this study, we set out to assess a mouse monoclonal antibody (MoMAb) cocktail with the ultimate goal to develop a product at the lowest possible cost that can be used …

Traumatic Thoracic Asia A Examinations And Potential For Clinical Trials, James S. Harrop, Md, Mitchell G. Maltenfort, Phd, Fred H. Geisler, Md, Phd, William Coleman, Phd, Linda A.T. Jones, Pt, Ms, Edward Wirth, Md, Alexander Vaccaro, Md, Phd

Department of Neurosurgery Faculty Papers

Study Design: Retrospective review of prospective database

Objectives: To define the variability of neurologic examination and recovery after non-penetrating complete thoracic spinal cord injuries (ASIA A).

Background Data: Neurologic examinations after SCI can be difficult and inconsistent. Unlike cervical SCI patients, alterations in thoracic (below T1) complete SCI (ASIA A – based on the ASIA Impairment Scale [AIS]) patients’ exams are based only on sensory testing, thus changes in the neurological level (NL) are determined only by sensory changes.

Methods: A retrospective review of the placebo control patients in a multicenter prospective database utilized for the pharmacologic trial of Sygen. …

Cannabinoid Receptor Type 2 Activation Induces A Microglial Anti-Inflammatory Phenotype And Reduces Migration Via Mkp Induction And Erk Dephosphorylation, Edgar A. Romero-Sandoval, Ryan Horvath, Russell P. Landry, Joyce A. Deleo

Dartmouth Scholarship

Cannabinoid receptor type 2 (CBR2) inhibits microglial reactivity through a molecular mechanism yet to be elucidated. We hypothesized that CBR2 activation induces an anti-inflammatory phenotype in microglia by inhibiting extracellular signal-regulated kinase (ERK) pathway, via mitogen-activated protein kinase-phosphatase (MKP) induction. MKPs regulate mitogen activated protein kinases, but their role in the modulation of microglial phenotype is not fully understood.

The Combined Effect Of In-Situ Tumor And Irradiation On Peritumoral Brain Vasculature, Janice Ann Zawaski

Theses and Dissertations (ETD)

In the USA, 200,000 brain tumors are diagnosed each year with glioma representing 8.4% of the 200,000. The standard treatment for glioma consists of surgical resection, when possible, followed by radiation therapy (RT) and/or chemotherapy. Radiation therapy is one of the most effective treatments of brain tumors; however, the therapeutic ratio of RT is limited by damage to the normal tissue. We hypothesize that tumor growth has an adverse effect on the peritumoral tissue through the angiogenic/inflammatory environment it creates rendering it susceptible to further damage by RT which may be prevented by using anti-angiogenic/anti-inflammatory agents. We have developed a …

Substrate And Regulation Of Mitochondrial Μ-Calpain, Aashish Joshi

University of Kentucky Doctoral Dissertations

μ -Calpain is localized to the mitochondrial intermembrane space. Apoptosisinducing factor (AIF), which executes caspase-independent cell death, is also localized to the mitochondrial intermembrane space. Following processing at the N-terminus, AIF becomes truncated (tAIF) and is released from mitochondria. The protease responsible for AIF processing has not been established. The same submitochondrial localization of mitochondrial μ-calpain and AIF gives support to the hypothesis that mitochondrial μ-calpain may be responsible for processing AIF. Atractyloside-induced tAIF release in rat liver mitochondria was inhibited by cysteine protease inhibitor MDL28170, but not by calpain inhibitors PD150606 or calpastatin. Moreover, μ-calpain immunoreactivity was difficult to …

Role Of Cyclophilin D In Secondary Spinal Cord And Brain Injury, Jordan Mills Clark

University of Kentucky Doctoral Dissertations

In the hours and days following acute CNS injury, a secondary wave of events is initiated that exacerbate spinal tissue damage and neuronal cell death. A potential mechanism driving these secondary events is opening of the mitochondrial permeability transition pore (mPTP) and subsequent release of several cell death proteins. Previous studies have shown that inhibition of cyclophilin D(CypD), the key regulating component in mPTP opening, was protective against insults that induce necrotic cell death. We therefore hypothesized that CypD-null mice would show improved functional and pathological outcomes following spinal cord injury (SCI) and traumatic brain injury (TBI). Moderate and severe …

Glutamate Regulation In The Hippocampal Trisynaptic Pathway In Aging And Status Epilepticus, Michelle Lee Stephens

University of Kentucky Doctoral Dissertations

A positive correlation exists between increasing age and the incidence of hippocampal-associated dysfunction and disease. Normal L-glutamate neurotransmission is absolutely critical for hippocampal function, while abnormal glutamate neurotransmission has been implicated in many neurodegenerative diseases. Previous studies, overwhelmingly utilizing ex vivo methods, have filled the literature with contradicting reports about hippocampal glutamate regulation during aging. For our studies, enzyme-based ceramic microelectrode arrays (MEA) were used for rapid (2 Hz) measurements of extracellular glutamate in the hippocampal trisynaptic pathway of young (3-6 months), late-middle aged (18 mo.) and aged (24 mo.) urethane-anesthetized Fischer 344 rats. Compared to young animals, glutamate terminals …

Age May Be Hazardous To Outcome Following Traumatic Brain Injury: The Mitochondrial Connection, Lesley Knight Gilmer

University of Kentucky Doctoral Dissertations

Older individuals sustaining traumatic brain injury (TBI) experience a much higher incidence of morbidity and mortality. This age-related exacerbated response to neurological insult has been demonstrated experimentally in aged animals, which can serve as a model to combat this devastating clinical problem. The reasons for this worse initial response are unknown but may be related to age-related changes in mitochondrial respiration.

Evidence is shown that mitochondrial dysfunction occurs early following traumatic brain injury (TBI), persists long after the initial insult, and is severitydependent. Synaptic and extrasynaptic mitochondrial fractions display distinct respiration capacities, stressing the importance to analyze these fractions separately. …

The Efficacy Of Surgical Decompression Before 24 Hours Versus 24 To 72 Hours In Patients With Spinal Cord Injury From T1 To L1--With Specific Consideration On Ethics: A Randomized Controlled Trial., Vafa Rahimi-Movaghar, Soheil Saadat, Alexander R Vaccaro, Seyed Mohammad Ghodsi, Mohammad Samadian, Arya Sheykhmozaffari, Seyed Mohammad Safdari, Bahram Keshmirian

Department of Neurosurgery Faculty Papers

BACKGROUND: There is no clear evidence that early decompression following spinal cord injury (SCI) improves neurologic outcome. Such information must be obtained from randomized controlled trials (RCTs). To date no large scale RCT has been performed evaluating the timing of surgical decompression in the setting of thoracolumbar spinal cord injury. A concern for many is the ethical dilemma that a delay in surgery may adversely effect neurologic recovery although this has never been conclusively proven. The purpose of this study is to compare the efficacy of early (before 24 hours) verse late (24-72 hours) surgical decompression in terms of neurological …

In Vivo Trafficking Of Endogenous Opioid Receptors, Yulin Wang, Elisabeth J. Van Bockstaele, Lee-Yuan Liu-Chen

Department of Neurosurgery Faculty Papers

Studies on trafficking of endogenous opioid receptors in vivo are subject of the present review. In many of the in vivo studies, the use of semi-quantitative immuno-electron microscopy is the approach of choice. Endogenous opioid receptors display differential subcellular distributions with μ opioid receptor (MOPR) being mostly present on the plasma membrane and δ- and κ-opioid receptors (DOPR and KOPR, respectively) having a significant intracellular pool. Etorphine and DAMGO cause endocytosis of the MOPR, but morphine does not, except in some dendrites. Interestingly, chronic inflammatory pain and morphine treatment promote trafficking of intracellular DOPR to the cell surface which may …

Neuroendocrine Peptides Neuropeptide-Y (Npy) And Peptide-Yy (Pyy) Suppress Cl- Secretion And K+ Secretion In Guinea Pig Distal Colon Through Action At Y2-Receptors, Susan T. Halm, Jin Zhang, Dan R. Halm

Neuroscience, Cell Biology & Physiology Faculty Publications

Electrogenic Cl^– and K⁺ secretion in isolated mucosa from guinea pig distal colon measured as short-circuit current (I_sc) and transepithelial conductance (G_t) were stimulated by epinephrine (epi), prostaglandin-E₂ (PGE₂) and carbachol (CCh). neuropeptide-Y (NPY) and peptide-YY (PYY) inhibited by 60% Cl^– secretion activated by either PGE₂ or PGE₂+CCh with EC₅₀’s of 16nM and 6nM, respectively. Neither peptide markedly inhibited the transient component of the PGE₂+CCh response. Immunoreactivity (IR) for NPY was present in enteric ganglia and in proximity with crypts. Basolateral membranes of …

Viral Vectors In The Research Laboratory: Just How Safe Are They?, Dawn P. Wooley, Kimberly Kay Morris, Robert Mcrae, John C. Trefry

Neuroscience, Cell Biology & Physiology Faculty Publications

No abstract provided.

Immune Evasion By Rabies Viruses Through The Maintenance Of Blood-Brain Barrier Integrity., Anirban Roy, Douglas C. Hooper

Department of Cancer Biology Faculty Papers

The attenuated rabies virus (RV) strain Challenge Virus Standard (CVS)-F3 and a highly pathogenic strain associated with the silver-haired bats (SHBRV) can both be cleared from the central nervous system (CNS) tissues by appropriate antiviral immune mechanisms if the effectors are provided access across the blood-brain barrier (BBB). In the case of SHBRV infection, antiviral immunity develops normally in the periphery but fails to open the BBB, generally resulting in a lethal outcome. To determine whether or not an absence in the CNS targeted immune response is associated with the infection with other pathogenic RV strains, we have assessed the …

Investigating The Complexity Of Respiratory Patterns During The Laryngeal Chemoreflex, Andrei Dragomir, Yasemin Akay, Aidan K. Curran, Metin Akay

Dartmouth Scholarship

The laryngeal chemoreflex exists in infants as a primary sensory mechanism for defending the airway from the aspiration of liquids. Previous studies have hypothesized that prolonged apnea associated with this reflex may be life threatening and might be a cause of sudden infant death syndrome. In this study we quantified the output of the respiratory neural network, the diaphragm EMG signal, during the laryngeal chemoreflex and eupnea in early postnatal (3–10 days) piglets. We tested the hypothesis that diaphragm EMG activity corresponding to reflex-related events involved in clearance (restorative) mechanisms such as cough and swallow exhibit lower complexity, suggesting that …

Supracutaneous Vibrotactile Perception Threshold At Various Non-Glabrous Body Loci, Miriam Bikah, M. Susan Hallbeck, John H. Flowers

Department of Psychology: Faculty Publications

Researchers at the University of Nebraska–Lincoln are currently designing a wearable/portable neutron detector. As an alerting mechanism, the device will transmit vibration to the wearer’s skin in the presence of hazardous levels of neutron radiation. The present study was designed to help in the ergonomically correct body placement of the neutron detection device while providing numerical values for vibratory thresholds at the surface of various non-glabrous body loci. The aim of the study was to investigate the underlying effects of locus stimulated, amount of subcutaneous fat around a specific body site and gender on low frequency vibration thresholds. Thirty-six participants, …

Abeta42 Mutants With Different Aggregation Profiles Induce Distinct Pathologies In Drosophila., Koichi Iijima, Hsueh-Cheng Chiang, Stephen A Hearn, Inessa Hakker, Anthony Gatt, Christopher Shenton, Linda Granger, Amy Leung, Kanae Iijima-Ando, Yi Zhong

Department of Biochemistry and Molecular Biology Faculty Papers

Aggregation of the amyloid-beta-42 (Abeta42) peptide in the brain parenchyma is a pathological hallmark of Alzheimer's disease (AD), and the prevention of Abeta aggregation has been proposed as a therapeutic intervention in AD. However, recent reports indicate that Abeta can form several different prefibrillar and fibrillar aggregates and that each aggregate may confer different pathogenic effects, suggesting that manipulation of Abeta42 aggregation may not only quantitatively but also qualitatively modify brain pathology. Here, we compare the pathogenicity of human Abeta42 mutants with differing tendencies to aggregate. We examined the aggregation-prone, EOFAD-related Arctic mutation (Abeta42Arc) and an artificial mutation (Abeta42art) that …

Trk: A Neuromodulator Of Age-Specific Behavioral And Neurochemical Responses To Cocaine In Mice., Michelle Niculescu, Shane A Perrine, Jonathan S Miller, Michelle E Ehrlich, Ellen M Unterwald

Farber Institute for Neuroscience Faculty Papers

Responses to psychostimulants vary with age, but the molecular etiologies of these differences are largely unknown. The goal of the present research was to identify age-specific behavioral and molecular adaptations to cocaine and to elucidate the mechanisms involved therein. Postweanling, periadolescent, and adult male CD-1 mice were exposed to cocaine (20 mg/kg) for 7 d. The rewarding effects of cocaine were assessed, as were the response to a Trk antagonist and the regulation of dopamine and cAMP-regulated phosphoprotein, 32 kDa (DARPP-32). Cocaine was rewarding in both periadolescent and adult mice using a conditioned place preference procedure. In contrast, postweanling mice …

A Novel And Generalizable Organotypic Slice Platform To Evaluate Stem Cell Potential For Targeting Pediatric Brain Tumors., Shengwen Calvin Li, William Gunter Loudon

Department of Cancer Biology Faculty Papers

Brain tumors are now the leading cause of cancer-related deaths in children under age 15. Malignant gliomas are, for all practical purposes, incurable and new therapeutic approaches are desperately needed. One emerging strategy is to use the tumor tracking capacity inherent in many stem cell populations to deliver therapeutic agents to the brain cancer cells. Current limitations of the stem cell therapy strategy include that stem cells are treated as a single entity and lack of uniform technology is adopted for selection of clinically relevant sub-populations of stem cells. Specifically, therapeutic success relies on the selection of a clinically competent …

Role Of Reactive Oxygen Species Peroxynitrite In Traumatic Spinal Cord Injury, Yiqin Xiong

University of Kentucky Doctoral Dissertations

Peroxynitrite (PN, ONOO-), formed by nitric oxide radical (^•NO) and superoxide radical (O2^•-), plays an important role in post-traumatic oxidative damage. In the early work, we determined the temporal characteristics of PN-derived oxidative damage in a rat spinal cord injury (SCI) model. Our results showed 3-nitrotyrosine (3-NT), a specific marker for PN, rapidly accumulated at early time points (1 hr, 3 hrs), after when it plateaued and the high level was sustained to 1 week post injury. The co-localization of 3-NT and lipid peroxidation derived-4-HNE observed in immunohistochemistry indicates PN is involved in lipid peroxidative as …

The Underlying Mechanism(S) Of Fasting Induced Neuroprotection After Moderate Traumatic Brain Injury, Laurie Michelle Helene Davis

University of Kentucky Doctoral Dissertations

Traumatic brain injury (TBI) is becoming a national epidemic, as it accounts for 1.5 million cases each year. This disorder affects primarily the young population and elderly. Currently, there is no treatment for TBI, which means that ~2% of the U.S. population is currently living with prolonged neurological damage and dysfunction. Recently, there have been many studies showing that TBI negatively impacts mitochondrial function. It has been proposed that in order to save the cell from destruction mitochondrial function must be preserved. The ketogenic diet, originally designed to mimic fasting physiology, is effective in treating epilepsy. Therefore, we have used …

Role Of The Reactive Oxygen Species Peroxynitrite In Traumatic Brain Injury, Ying Deng

University of Kentucky Doctoral Dissertations

Reactive oxygen species (ROS) is cytotoxic to the cell and is known to contribute to secondary cell death following primary traumatic brain injury (TBI). We described in our study that PN is the main mediator for both lipid peroxidation and protein nitration, and occurred almost immediately after injury. As a downstream factor to oxidative damage, the peak of Ca2+-dependent, calpainmediated cytoskeletal proteolysis preceded that of neurodegeneration, suggesting that calpain-mediated proteolysis is the common pathway leading to neuronal cell death. The time course study clearly elucidated the interrelationship of these cellular changes following TBI, provided window of opportunity for pharmacological intervention. …

The Effect Of Pparγ Activation By Pioglitazone On The Lipopolysaccharide-Induced Pge2 And No Production: Potentialunderlying Alteration Of Signaling Transduction, Bin Xing

University of Kentucky Doctoral Dissertations

Microglia-mediated neuroinflammation plays an important role in the pathogenesis of Parkinson's disease (PD). Uncontrolled microglia activation produces major proinflammatory factors including cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) that may cause dopaminergic neurodegeneration. Peroxisome proliferator-activated receptor γ (PPARγ) agonist pioglitazone has potent antiinflammatory property. We hypothesize pioglitazone protects dopaminergic neuron from lipopolysaccharide (LPS)-induced neurotoxicity by interacting with relevant signal pathways, inhibiting microglial activation and decreasing inflammatory mediators.

First, the neuroprotection of pioglitazone was explored. Second, the signaling transductions such as jun N-terminal kinase (JNK) and the interference with these pathways by pioglitazone were investigated. Third, the effect of …

Spinal Cord Stimulation: An Update., Steven Falowski, Amanda Celii, Ashwini Sharan

Department of Neurosurgery Faculty Papers

Spinal cord stimulation has been used in the treatment of many chronic pain disorders since 1967. In this update, the indications for spinal cord stimulation are reviewed with attention to recent publications. A focused review of the literature on abdominal and visceral pain syndromes is also provided. Furthermore, the technology has evolved from the use of monopolar electrodes to complex electrode arrays. Similarly, the power source has changed from a radio frequency-driven system to a rechargeable impulse generator. These topics are covered, along with a short discussion of implant technique. Finally, we include a review of complications of such therapy. …

Neuroadaptive Changes In The Mesocortical Glutamatergic System During Nicotine Self-Administration And After Extinction In Rats, Fan Wang

Theses and Dissertations (ETD)

The mesocorticolimbic pathway is critical in almost all aspects of drug abuse, including nicotine. Though many of the neurochemical and molecular effects of nicotine have been well studied, nicotine’s long-term neuroadaptive effects, specifically within the mesocorticolimbic pathway, are largely undefined. Thus, in current study, we determined the neuroadaptive changes in the mesocortical glutamatergic system during chronic nicotine self-administration (SA), which emulates important aspects of nicotine intake by humans, and after extinction. In the initial study, after 18 days of nicotine SA, in the medial prefrontal cortex (mPFC), NMDA receptor subunit 2A (NR2A) and NR2B were increased by 67% and 83%, …

Role Of Medial Prefrontal Cortical Group Ii Metabotropic Glutamate Receptor In The Development Of Cocaine Sensitization, Xiaohu Xie

Theses and Dissertations (ETD)

The current studies examined the role of medial prefrontal cortical (mPFC) group II metabotropic glutamate receptors (mGluR_2/3) in the development of cocaine sensitization. Initial studies demonstrated that intra-mPFC injection of the mGluR_2/3 receptor agonist, APDC, dose-dependently reduced acute behavioral response to cocaine (0.015-15 nmol/side with significant effects starting at 1.5nmol/side). The effects of APDC were prevented by intra-mPFC co-injections of an mGluR_2/3 antagonist, LY341495 (1.5 nmol/side). Repeated intra-mPFC APDC (1.5 nmol/side) injections also prevented the initiation of behavioral and neurochemical sensitization, which is defined as enhanced nucleus accumbens (NAc) dopamine response to cocaine. Once sensitization was …

Anti-Tumor Effect Of Doxycycline On Glioblastoma Cells, Andrea Wang-Gillam, Eric Siegel, Debra A. Mayes, Laura F. Hutchins, Yi-Hong Zhou

Neuroscience, Cell Biology & Physiology Faculty Publications

AIM: Glioblastoma multiforme (GBM) is the most common primary brain tumor in humans, and it is highly invasive. Doxycycline, first identified as an antimicrobial agent, is a nonspecific inhibitor of matrix metalloproteinases (MMPs). Our objective was to investigate the anti-MMP effect of doxycycline at therapeutically acceptable levels on glioma cells in vitro.

METHODS: The MTT assay was used to determine the anti-proliferative effects of doxycycline. MMP2 activity and expression were determined by gelatinase zymography and real-time quantitative RT-PCR, respectively. Cell invasion was assessed by Matrigel invasion assay.

RESULTS: Doxycycline exerted mild anti-proliferative effects on all three glioma cell lines …

Iron Dysregulation And Inflammation In Alzheimer’S Disease, Shino D. Magaki

Loma Linda University Electronic Theses, Dissertations & Projects

Alzheimer’s disease (AD) is the most common form of senile dementia in the US and worldwide but the causes of its pathogenesis are currently unknown. In this study, we examined two processes that have been implicated in the early stages of AD and other forms of neurodegeneration, iron dysregulation and inflammation, both of which can promote the increased production of amyloid precursor protein (APP). We have measured different pools of brain iron in transgenic iron regulatory protein 2 knockout (IRP2-/-) mice in the early stages of neurodegeneration and in affected brain regions from AD patients at different stages of the …

Alzheimer's Disease: Cholesterol, Membrane Rafts, Isoprenoids And Statins, Patrick C. Reid, Yasuomi Urano, Tatsuhiko Kodama, Takao Hamakubo

Dartmouth Scholarship

Alzheimer's disease (AD) is a heterogeneous neurodegenerative disorder and the most prevalent form of dementia worldwide. AD is characterized pathologically by amyloid-? plaques, neurofibrillary tangles and neuronal loss, and clinically by a progressive loss of cognitive abilities. At present, the fundamental molecular mechanisms underlying the disease are unclear and no treatment for AD is known. Epidemiological evidence continues to mount linking vascular diseases, such as hypertension and diabetes, and hypercholesterolaemia with an increased risk for developing AD. A growing amount of evidence suggests a mechanistic link between cholesterol metabolism in the brain and the formation of amyloid plaques in AD …