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Articles 91 - 120 of 223

Full-Text Articles in Medical Sciences

The Reliability And Validity Of Functional Brain Connectivity Compared To A Self-Reported Measure Of Pain, Ali Alsouhibani Jan 2016

The Reliability And Validity Of Functional Brain Connectivity Compared To A Self-Reported Measure Of Pain, Ali Alsouhibani

Maria Dittman Library Research Competition: Student Award Winners

Pain is a multidimensional perception that is complex in nature. It is a unitary construct that includes overlapping domains such as intensity, affect, quality, and frequency. These domains do not reflect the amount of tissue damage. It reflects the end result of the perception of pain in which multiple biopsychosocial factors are involved (Gatchel et al., 2007). Multiple self-reported measures have been used in an attempt to capture most factors that may influence pain such as psychological factors. However, there is no one scale that can be used to characterize pain as a whole with all its factors. Furthermore, physical …


N-Acetylcysteine Decreases Binge Eating In A Rodent Model, M. M. Hurley, Jon M. Resch, Brian Maunze, M. M. Frenkel, David A. Baker, Sujean Choi Jan 2016

N-Acetylcysteine Decreases Binge Eating In A Rodent Model, M. M. Hurley, Jon M. Resch, Brian Maunze, M. M. Frenkel, David A. Baker, Sujean Choi

Biomedical Sciences Faculty Research and Publications

Binge-eating behavior involves rapid consumption of highly palatable foods leading to increased weight gain. Feeding in binge disorders resembles other compulsive behaviors, many of which are responsive to N-acetylcysteine (NAC), which is a cysteine prodrug often used to promote non-vesicular glutamate release by a cystine–glutamate antiporter. To examine the potential for NAC to alter a form of compulsive eating, we examined the impact of NAC on binge eating in a rodent model. Specifically, we monitored consumption of standard chow and a high-fat, high carbohydrate western diet (WD) in a rodent limited-access binge paradigm. Before each session, rats received either …


Stress-Induced Reinstatement Of Drug Seeking: 20 Years Of Progress, John R. Mantsch, David A. Baker, Douglas Funk, Anh D. Lê, Yavin Shaham Jan 2016

Stress-Induced Reinstatement Of Drug Seeking: 20 Years Of Progress, John R. Mantsch, David A. Baker, Douglas Funk, Anh D. Lê, Yavin Shaham

Biomedical Sciences Faculty Research and Publications

In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, …


Cb1 Receptor Antagonism Blocks Stress-Potentiated Reinstatement Of Cocaine Seeking In Rats, Jayme R. Mcreynolds, Elizabeth M. Doncheck, Oliver Vranjkovic, Geoffrey S. Ganzman, David A. Baker, Cecilia J. Hillard, John R. Mantsch Jan 2016

Cb1 Receptor Antagonism Blocks Stress-Potentiated Reinstatement Of Cocaine Seeking In Rats, Jayme R. Mcreynolds, Elizabeth M. Doncheck, Oliver Vranjkovic, Geoffrey S. Ganzman, David A. Baker, Cecilia J. Hillard, John R. Mantsch

Biomedical Sciences Faculty Research and Publications

Rationale

Under some conditions, stress, rather than directly triggering cocaine seeking, potentiates reinstatement to other stimuli, including a subthreshold cocaine dose. The mechanisms responsible for stress-potentiated reinstatement are not well defined. Endocannabinoid signaling is increased by stress and regulates synaptic transmission in brain regions implicated in motivated behavior.

Objectives

The objective of this study was to test the hypothesis that cannabinoid type 1 receptor (CB1R) signaling is required for stress-potentiated reinstatement of cocaine seeking in rats.

Methods

Following i.v. cocaine self-administration (2 h access/day) and extinction in male rats, footshock stress alone does not reinstate cocaine seeking but reinstatement is …


The Level Of Nmda Receptor In The Membrane Modulates Amyloid-Β Association And Perforation, Christian Peters, Fernando J. Sepúlveda, Eduardo Fernández-Pérez, Robert W. Peoples, Luis G. Aguayo Jan 2016

The Level Of Nmda Receptor In The Membrane Modulates Amyloid-Β Association And Perforation, Christian Peters, Fernando J. Sepúlveda, Eduardo Fernández-Pérez, Robert W. Peoples, Luis G. Aguayo

Biomedical Sciences Faculty Research and Publications

Alzheimer’s disease is a neurodegenerative disorder that affects mostly the elderly. The main histopathological markers are the senile plaques formed by amyloid-β peptide (Aβ) aggregates that can perforate the plasma membrane of cells, increasing the intracellular calcium levels and releasing synaptic vesicles that finally lead to a delayed synaptic failure. Several membrane proteins and lipids interact with Aβ affecting its toxicity in neurons. Here, we focus on NMDA receptors (NMDARs) as proteins that could be modulating the association and neurotoxic perforation induced by Aβ on the plasma membrane. In fact, our results showed that decreasing NMDARs, using enzymatic or siRNA …


The Relationship Of Spasticity And Impairments In Force Regulation And Neuromuscular Fatigue Post Stroke, Reivian Berrios Barillas Oct 2015

The Relationship Of Spasticity And Impairments In Force Regulation And Neuromuscular Fatigue Post Stroke, Reivian Berrios Barillas

Dissertations (1934 -)

Hyperreflexia that causes muscle spasticity may contribute to limitations in force regulation and walking ability post stroke. Additionally, neuromuscular fatigue may reduce force regulation, which is important because fatigue can assist to strengthen muscles that control walking. Hyperreflexia may be caused by cortical disinhibition that allows Ia afferents to amplify excitatory synaptic inputs to motoneuron pools. Cortical disinhibition is presumably caused by stroke-related motor cortex damage. Although, other excitatory synaptic sources to motoneurons contribute to motor control, hyperreflexia may be one contributor that affects stroke survivors. However, hyperreflexia is reported infrequently to effect force regulation post stroke. The goal was …


A Neurobiological Pathway That Mediates Stress-Induced Drug Use, Oliver Vranjkovic Oct 2015

A Neurobiological Pathway That Mediates Stress-Induced Drug Use, Oliver Vranjkovic

Dissertations (1934 -)

Cocaine addiction represents a tremendous health and financial burden on our society and the high rate of relapse to cocaine use in abstinent addicts represents a major barrier to effective therapy. Thus, understanding the factors that contribute to relapse and the underlying neurobiological processes is important for guiding the development of treatment for addiction. Stressful life events often trigger drug use in recovering addicts. The contribution of stress to drug use is problematic due to the unpredictable and often uncontrollable nature of stress. A growing literature indicates that norepinephrine and corticotropin releasing factor (CRF) in the brain play key roles …


Neural Plasticity In Response To Intervention In Adolescents With Autism Spectrum Disorders, Sheryl Jayne Stevens Jul 2015

Neural Plasticity In Response To Intervention In Adolescents With Autism Spectrum Disorders, Sheryl Jayne Stevens

Dissertations (1934 -)

Current theories of Autism Spectrum Disorders (ASD) suggest that they may develop from the transactional interaction between biological risk factors and environmental processes (Dawson et al., 2009). Due to the brain’s experience-expectant nature, one’s degree of social exposure may have a significant impact on their brain development and behavioral presentation. In addition to the primary critical neurodevelopmental period identified in early childhood, recent research has demonstrated a second period of substantial neurodevelopment during the adolescent period (Sisk & Foster, 2004). This study investigated the neural and behavioral impact of participation in an empirically validated behavioral intervention (The Program for the …


Drug Predictive Cues Activate Aversion-Sensitive Striatal Neurons That Encode Drug Seeking, Daniel S. Wheeler, Mykel A. Robble, Emily M. Hebron, Matthew J. Dupont, Amanda L. Ebben, Robert A. Wheeler May 2015

Drug Predictive Cues Activate Aversion-Sensitive Striatal Neurons That Encode Drug Seeking, Daniel S. Wheeler, Mykel A. Robble, Emily M. Hebron, Matthew J. Dupont, Amanda L. Ebben, Robert A. Wheeler

Biomedical Sciences Faculty Research and Publications

Drug-associated cues have profound effects on an addict’s emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, …


Genetic And Molecular Analysis Of Dec-11 In C. Elegans' Intestinal Pacemaker Activity, Adele Joan Gordon Apr 2015

Genetic And Molecular Analysis Of Dec-11 In C. Elegans' Intestinal Pacemaker Activity, Adele Joan Gordon

Master's Theses (2009 -)

Rhythmic behaviors are ubiquitous phenomena in plant and animal phyla. Ultradian rhythmic behaviors occur with a period of less than 24 hours and include such rhythmic behaviors as the beating of the heart and peristalsis in the gut. The nematode C. elegans exhibits three well-characterized ultradian rhythmic behaviors: ovulation, pharyngeal pumping, and the defecation motor program (DMP). The DMP occurs every ~45 seconds in wild-type worms and comprises three distinct muscle contractions: a posterior body contraction (pBoc), an anterior body contraction (aBoc), and an enteric muscle contraction (Emc), which is coupled to expulsion (Exp). The rhythmicity of the DMP is …


Overexpression Of Sox11 Promotes Corticospinal Tract Regeneration After Spinal Injury While Interfering With Functional Recovery, Zimei Wang, Ashley Reynolds, Adam Kirry, Christopher Nienhaus, Murray G. Blackmore Feb 2015

Overexpression Of Sox11 Promotes Corticospinal Tract Regeneration After Spinal Injury While Interfering With Functional Recovery, Zimei Wang, Ashley Reynolds, Adam Kirry, Christopher Nienhaus, Murray G. Blackmore

Biomedical Sciences Faculty Research and Publications

Embryonic neurons, peripheral neurons, and CNS neurons in zebrafish respond to axon injury by initiating pro-regenerative transcriptional programs that enable axons to extend, locate appropriate targets, and ultimately contribute to behavioral recovery. In contrast, many long-distance projection neurons in the adult mammalian CNS, notably corticospinal tract (CST) neurons, display a much lower regenerative capacity. To promote CNS repair, a long-standing goal has been to activate pro-regenerative mechanisms that are normally missing from injured CNS neurons. Sox11 is a transcription factor whose expression is common to a many types of regenerating neurons, but it is unknown whether suboptimal Sox11 expression contributes …


Regulation Of System XC- By Pharmacological Manipulation Of Cellular Thiols, Rebecca Albano, Nicholas J. Raddatz, Julie Hjelmhaug, David A. Baker, Doug Lobner Jan 2015

Regulation Of System XC- By Pharmacological Manipulation Of Cellular Thiols, Rebecca Albano, Nicholas J. Raddatz, Julie Hjelmhaug, David A. Baker, Doug Lobner

Biomedical Sciences Faculty Research and Publications

The cystine/glutamate exchanger (system xc-) mediates the transport of cystine into the cell in exchange for glutamate. By releasing glutamate, system xc- can potentially cause excitotoxicity. However, through providing cystine to the cell, it regulates the levels of cellular glutathione (GSH), the main endogenous intracellular antioxidant, and may protect cells against oxidative stress. We tested two different compounds that deplete primary cortical cultures containing both neurons and astrocytes of intracellular GSH, L-buthionine-sulfoximine (L-BSO), and diethyl maleate (DEM). Both compounds caused significant concentration and time dependent decreases in intracellular GSH levels. However; DEM caused an increase …


Expression Patterns Of Bdnf With Central Anorexigenic Signaling Pathways Involving Pacap In The Hypothalamic Ventromedial Nuclei, Brian Maunze, Matthew M. Hurley, Jon M. Resch, M. J. Reilley, E. M. Wassmann, Sujean Choi Jan 2015

Expression Patterns Of Bdnf With Central Anorexigenic Signaling Pathways Involving Pacap In The Hypothalamic Ventromedial Nuclei, Brian Maunze, Matthew M. Hurley, Jon M. Resch, M. J. Reilley, E. M. Wassmann, Sujean Choi

Biomedical Sciences Faculty Research and Publications

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a 38-amino acid polypeptide belonging to the secretin super family of peptides. PACAP binds to its type 1 receptor (PAC1R) with greater affinity than for the receptors for vasoactive intestinal polypeptides (VIP), VPAC1 and VPAC2. Although mRNA for PACAP and its receptor PAC1R are found throughout the central nervous system, they are abundantly expressed in the hypothalamic ventromedial nuclei (VMN). In male Sprague Dawley rats, infusions of PACAP into the VMN produce a robust decrease in food intake with concomitant increased energy expenditure, decreased body weight, and significantly elevated brain-derived neurotrophic factor (BDNF) mRNA …


Patterns Of Barbell Acceleration During The Snatch In Weightlifting Competition, Kristof Kipp, Chad Harris Jan 2015

Patterns Of Barbell Acceleration During The Snatch In Weightlifting Competition, Kristof Kipp, Chad Harris

Exercise Science Faculty Research and Publications

The purpose of this study was to determine the association between weightlifting performance and vertical barbell acceleration patterns. Barbell kinematic time-series data were tracked from 18 snatches from six weightlifters during a regional weightlifting competition. These data were used to calculate vertical barbell accelerations. Time-series data were normalised to 100% of lift phase, defined as the time interval between barbell lift-off and maximum height of the barbell during each snatch lift. The time-series data were then entered into a pattern recognition algorithm that extracted principal patterns and calculated principal pattern scores. Body mass-normalised lift weight, which was used to quantify …


Pacap And Cocaine Reinstatement: A Neuropeptide Expressed By Corticostriatal Neurons That Regulates Nucleus Accumbens Astrocytes, Linghai Kong, E. Hess, Brian Maunze, Matthew M. Hurley, Khadijah Makky, Sujean Choi, John R. Mantsch, David A. Baker Jan 2015

Pacap And Cocaine Reinstatement: A Neuropeptide Expressed By Corticostriatal Neurons That Regulates Nucleus Accumbens Astrocytes, Linghai Kong, E. Hess, Brian Maunze, Matthew M. Hurley, Khadijah Makky, Sujean Choi, John R. Mantsch, David A. Baker

Biomedical Sciences Faculty Research and Publications

Drug addiction involves heightened relapse vulnerability arising from persistent drug-induced neuro-adaptations, including a) hypofrontality which is thought to reflect reduced firing of cortical afferents to the nucleus accumbens (NAcc) and b) altered glutamate homeostasis in NAcc that likely involves reduced glutamate release and uptake by astrocytes. An important question is whether these forms of pathological plasticity are functionally linked such that reduced corticostriatal firing may result in aberrant regulation of astrocytes in the NAcc. To begin to evaluate this possibility, we first determined whether neurons regulate system xc- (Sxc) activity, a mechanism of non-vesicular glutamate release by astrocytes. We found …


A New Obesity Model Reveals The Hypophagic Properties Of Pacap Involve The Regulation Of Homeostatic Feeding In The Ventromedial Hypothalamic Nucleus And Hedonic Feeding In The Nucleus Accumbens, Matthew M. Hurley, Brian Maunze, Jon M. Resch, Mogen M. Frenkel, M. J. Reilley, Megan E. Block, David A. Baker, Sujean Choi Jan 2015

A New Obesity Model Reveals The Hypophagic Properties Of Pacap Involve The Regulation Of Homeostatic Feeding In The Ventromedial Hypothalamic Nucleus And Hedonic Feeding In The Nucleus Accumbens, Matthew M. Hurley, Brian Maunze, Jon M. Resch, Mogen M. Frenkel, M. J. Reilley, Megan E. Block, David A. Baker, Sujean Choi

Biomedical Sciences Faculty Research and Publications

Binge eating in humans is a complex disorder that often involves discrete, compulsive feeding sessions of highly palatable foods even in the absence of a deprivation state or hunger. Binging can be effectively modeled in rodents by providing subjects with limited access to a palatable food source (Western Diet; WD) as an adjunct to ad lib access to normal chow (Standard Chow; SC). Although this design recapitulates several fundamental characteristics observed in binge eating disorder, the binge eating observed in this paradigm is likely a product of both hedonic and homeostatic drives with the need to balance energy stores still …


Behavioral Assessment Of Acute Inhibition Of System XC - In Rats, Victoria Lutgen, Jon M. Resch, Krista Qualmann, Nicholas J. Raddatz, Cristina Panhans, Ellen M. Olander, Linghai Kong, Sujean Choi, John R. Mantsch, David A. Baker Dec 2014

Behavioral Assessment Of Acute Inhibition Of System XC - In Rats, Victoria Lutgen, Jon M. Resch, Krista Qualmann, Nicholas J. Raddatz, Cristina Panhans, Ellen M. Olander, Linghai Kong, Sujean Choi, John R. Mantsch, David A. Baker

Biomedical Sciences Faculty Research and Publications

Rationale

Gaps in our understanding of glutamatergic signaling may be key obstacles in accurately modeling complex CNS diseases. System xc - is an example of a poorly understood component of glutamate homeostasis that has the potential to contribute to CNS diseases.

Objectives

This study aims to determine whether system xc - contributes to behaviors used to model features of CNS disease states.

Methods

In situ hybridization was used to map mRNA expression of xCT throughout the brain. Microdialysis in the prefrontal cortex was used to sample extracellular glutamate levels; HPLC was used to measure extracellular glutamate and tissue …


Augmented Cystine–Glutamate Exchange By Pituitary Adenylate Cyclase-Activating Polypeptide Signaling Via The Vpac1 Receptor, Jon M. Resch, Rebecca Albano, Xiaoqian Liu, Julie Hjelmhaug, Doug Lobner, David A. Baker, Sujean Choi Dec 2014

Augmented Cystine–Glutamate Exchange By Pituitary Adenylate Cyclase-Activating Polypeptide Signaling Via The Vpac1 Receptor, Jon M. Resch, Rebecca Albano, Xiaoqian Liu, Julie Hjelmhaug, Doug Lobner, David A. Baker, Sujean Choi

Biomedical Sciences Faculty Research and Publications

In the central nervous system, cystine import in exchange for glutamate through system xc- is critical for the production of the antioxidant glutathione by astrocytes, as well as the maintenance of extracellular glutamate. Therefore, regulation of system xc- activity affects multiple aspects of cellular physiology and may contribute to disease states. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuronally derived peptide that has already been demonstrated to modulate multiple aspects of glutamate signaling suggesting PACAP may also target activity of cystine–glutamate exchange via system xc-. In this study, 24-h treatment of primary cortical …


Phosphate And Acidosis Act Synergistically To Depress Peak Power In Rat Muscle Fibers, Cassandra R. Nelson, Edward P. Debold, Robert H. Fitts Nov 2014

Phosphate And Acidosis Act Synergistically To Depress Peak Power In Rat Muscle Fibers, Cassandra R. Nelson, Edward P. Debold, Robert H. Fitts

Biomedical Sciences Faculty Research and Publications

Skeletal muscle fatigue is characterized by the buildup of H+ and inorganic phosphate (Pi), metabolites that are thought to cause fatigue by inhibiting muscle force, velocity, and power. While the individual effects of elevated H+ or Pi have been well characterized, the effects of simultaneously elevating the ions, as occurs during fatigue in vivo, are still poorly understood. To address this, we exposed slow and fast rat skinned muscle fibers to fatiguing levels of H+ (pH 6.2) and Pi (30 mM) and determined the effects on contractile properties. At 30°C, elevated Pi …


Cyclic Ovarian Hormone Modulation Of Supraspinal Δ9-Tetrahydrocannabinol-Induced Antinociception And Cannabinoid Receptor Binding In The Female Rat, Alexa A. Wakley, Alisha A. Mcbride, Linda K. Vaughn, Rebecca M. Craft Sep 2014

Cyclic Ovarian Hormone Modulation Of Supraspinal Δ9-Tetrahydrocannabinol-Induced Antinociception And Cannabinoid Receptor Binding In The Female Rat, Alexa A. Wakley, Alisha A. Mcbride, Linda K. Vaughn, Rebecca M. Craft

Biomedical Sciences Faculty Research and Publications

Estrous cycle-related fluctuations in delta-9-tetrahydrocannabinol (THC)-induced antinociception have been observed in the rat. The aim of this study was to determine which major ovarian hormone modulates the antinociceptive effects of i.c.v. THC, and whether hormone modulation of THC's behavioral effects could be due to changes in brain cannabinoid receptors (CBr). Vehicle (oil) or hormones (estradiol or progesterone, or both) were administered to female rats on days 3 and 7 post-ovariectomy. On the morning or afternoon of day 8 or day 9, vehicle or THC (100 μg) was administered i.c.v. Paw pressure, tail withdrawal, locomotor activity and catalepsy tests were conducted …


Stress-Induced Cocaine Seeking Requires A Beta-2 Adrenergic Receptor-Regulated Pathway From The Ventral Bed Nucleus Of The Stria Terminalis That Regulates Crf Actions In The Ventral Tegmental Area, Oliver Vranjkovic, Paul J. Gasser, Clayton H. Gerndt, David A. Baker, John R. Mantsch Sep 2014

Stress-Induced Cocaine Seeking Requires A Beta-2 Adrenergic Receptor-Regulated Pathway From The Ventral Bed Nucleus Of The Stria Terminalis That Regulates Crf Actions In The Ventral Tegmental Area, Oliver Vranjkovic, Paul J. Gasser, Clayton H. Gerndt, David A. Baker, John R. Mantsch

Biomedical Sciences Faculty Research and Publications

The ventral bed nucleus of the stria terminalis (vBNST) has been implicated in stress-induced cocaine use. Here we demonstrate that, in the vBNST, corticotropin releasing factor (CRF) is expressed in neurons that innervate the ventral tegmental area (VTA), a site where the CRF receptor antagonist antalarmin prevents the reinstatement of cocaine seeking by a stressor, intermittent footshock, following intravenous self-administration in rats. The vBNST receives dense noradrenergic innervation and expresses β adrenergic receptors (ARs). Footshock-induced reinstatement was prevented by bilateral intra-vBNST injection of the β-2 AR antagonist, ICI-118,551, but not the β-1 AR antagonist, betaxolol. Moreover, bilateral intra-vBNST injection of …


Time Course Of Cocaine-Induced Behavioral And Neurochemical Plasticity, Victoria Lutgen, Linghai Kong, Kristen S. Kau, Aric Madayag, John Mantsch, David A. Baker Jul 2014

Time Course Of Cocaine-Induced Behavioral And Neurochemical Plasticity, Victoria Lutgen, Linghai Kong, Kristen S. Kau, Aric Madayag, John Mantsch, David A. Baker

Biomedical Sciences Faculty Research and Publications

Factors that result in augmented reinstatement, including increased withdrawal period duration and high levels of cocaine consumption, may provide insight into relapse vulnerability. The neural basis of augmented reinstatement may arise from more pronounced changes in plasticity required for reinstatement and/or the emergence of plasticity expressed only during a specific withdrawal period or under specific intake conditions. In this study, we examined the impact of withdrawal period duration and cocaine intake on the magnitude of cocaine-primed reinstatement and extracellular glutamate in the nucleus accumbens, which has been shown to be required for cocaine-primed reinstatement. Rats were assigned to self-administer under …


Inhibition Of Food Intake By Pacap In The Hypothalamic Ventromedial Nuclei Is Mediated By Nmda Receptors, Jon M. Resch, Brian Maunze, Kailynn A. Phillips, Sujean Choi Jun 2014

Inhibition Of Food Intake By Pacap In The Hypothalamic Ventromedial Nuclei Is Mediated By Nmda Receptors, Jon M. Resch, Brian Maunze, Kailynn A. Phillips, Sujean Choi

Biomedical Sciences Faculty Research and Publications

Central injections of pituitary adenylate cyclase-activating polypeptide (PACAP) into the ventromedial nuclei (VMN) of the hypothalamus produce hypophagia that is dependent upon the PAC1 receptor; however, the signaling downstream of this receptor in the VMN is unknown. Though PACAP signaling has many targets, this neuropeptide has been shown to influence glutamate signaling in several brain regions through mechanisms involving NMDA receptor potentiation via activation of the Src family of protein tyrosine kinases. With this in mind, we examined the Src-NMDA receptor signaling pathway as a target for PACAP signaling in the VMN that may mediate its effects on feeding behavior. …


Nature Of The Neurotoxic Membrane Actions Of Amyloid-Β On Hippocampal Neurons In Alzheimer's Disease, Fernando J. Sepúlveda, Humberto Fierro, Eduardo Fernandez, Carolina Castillo, Robert W. Peoples, Carlos Opazo, Luis G. Aguayo Mar 2014

Nature Of The Neurotoxic Membrane Actions Of Amyloid-Β On Hippocampal Neurons In Alzheimer's Disease, Fernando J. Sepúlveda, Humberto Fierro, Eduardo Fernandez, Carolina Castillo, Robert W. Peoples, Carlos Opazo, Luis G. Aguayo

Biomedical Sciences Faculty Research and Publications

The mechanism by which amyloid-β (Aβ) produces brain dysfunction in patients with Alzheimer's disease is largely unknown. According to previous studies, Aβ might share perforating properties with gramicidin, a well-accepted membrane-disrupting peptide. Therefore, we hypothesize that the key steps leading to synaptotoxicity by Aβ and gramicidin involve peptide aggregation, pore formation, and calcium dysregulation. Here, we show that Aβ and gramicidin form aggregates enriched in β-sheet structures using electron microscopy, and Thioflavin and Congo Red staining techniques. Also, we found that Aβ and gramicidin display fairly similar actions in hippocampal cell membranes, i.e. inducing Ca2+ entry and synaptoxicity characterized …


Fgf-2 Induces Neuronal Death Through Upregulation Of System Xc-, Xiaoqian Liu, Rebecca Albano, Doug Lobner Feb 2014

Fgf-2 Induces Neuronal Death Through Upregulation Of System Xc-, Xiaoqian Liu, Rebecca Albano, Doug Lobner

Biomedical Sciences Faculty Research and Publications

The cystine/glutamate antiporter (system xc-) transports cystine into cell in exchange for glutamate. Fibroblast growth factor-2 (FGF-2) upregulates system xc- selectively on astrocytes, which leads to increased cystine uptake, the substrate for glutathione production, and increased glutamate release. While increased intracellular glutathione can limit oxidative stress, the increased glutamate release can potentially lead to excitotoxicity to neurons. To test this hypothesis, mixed neuronal and glial cortical cultures were treated with FGF-2. Treatment with FGF-2 for 48 h caused a significant neuronal death in these cultures. Cell death was not observed in neuronal-enriched cultures, or astrocyte-enriched …


Neurobiological Mechanisms That Contribute To Stress-Related Cocaine Use, John R. Mantsch, Oliver Vranjkovic, Robert C. Twining, Paul J. Gasser, Jayme R. Mcreynolds, Jordan M. Blacktop Jan 2014

Neurobiological Mechanisms That Contribute To Stress-Related Cocaine Use, John R. Mantsch, Oliver Vranjkovic, Robert C. Twining, Paul J. Gasser, Jayme R. Mcreynolds, Jordan M. Blacktop

Biomedical Sciences Faculty Research and Publications

The ability of stressful life events to trigger drug use is particularly problematic for the management of cocaine addiction due to the unpredictable and often uncontrollable nature of stress. For this reason, understanding the neurobiological processes that contribute to stress-related drug use is important for the development of new and more effective treatment strategies aimed at minimizing the role of stress in the addiction cycle. In this review we discuss the neurocircuitry that has been implicated in stress-induced drug use with an emphasis on corticotropin releasing factor actions in the ventral tegmental area (VTA) and an important pathway from the …


Intrahypothalamic Pituitary Adenylate Cyclase-Activating Polypeptide Regulates Energy Balance Via Site-Specific Actions On Feeding And Metabolism, Jon Resch, Brian Maunze, Adriana K. Gerhardt, Samuel K. Magnuson, Kailynn A. Phillips, Sujean Choi Dec 2013

Intrahypothalamic Pituitary Adenylate Cyclase-Activating Polypeptide Regulates Energy Balance Via Site-Specific Actions On Feeding And Metabolism, Jon Resch, Brian Maunze, Adriana K. Gerhardt, Samuel K. Magnuson, Kailynn A. Phillips, Sujean Choi

Biomedical Sciences Faculty Research and Publications

Numerous studies have demonstrated that both the hypothalamic paraventricular nuclei (PVN) and ventromedial nuclei (VMN) regulate energy homeostasis through behavioral and metabolic mechanisms. Receptors for pituitary adenylate cyclase-activating polypeptide (PACAP) are abundantly expressed in these nuclei suggesting PACAP may be critical for the regulation of feeding behavior and body weight. To characterize the unique behavioral and physiological responses attributed to select hypothalamic cell groups, PACAP was site-specifically injected into the PVN or VMN. Overall food intake was significantly reduced by PACAP at both sites, however meal pattern analysis revealed only injections into the PVN produced significant reductions in meal size, …


Oral Branched-Chain Amino Acid Supplements That Reduce Brain Serotonin During Exercise In Rats Also Lower Brain Catecholamines, Sujean Choi, Briana Disilvio, Madelyn H. Fernstrom, John D. Fernstrom Nov 2013

Oral Branched-Chain Amino Acid Supplements That Reduce Brain Serotonin During Exercise In Rats Also Lower Brain Catecholamines, Sujean Choi, Briana Disilvio, Madelyn H. Fernstrom, John D. Fernstrom

Biomedical Sciences Faculty Research and Publications

Exercise raises brain serotonin release and is postulated to cause fatigue in athletes; ingestion of branched-chain amino acids (BCAA), by competitively inhibiting tryptophan transport into brain, lowers brain tryptophan uptake and serotonin synthesis and release in rats, and reputedly in humans prevents exercise-induced increases in serotonin and fatigue. This latter effect in humans is disputed. But BCAA also competitively inhibit tyrosine uptake into brain, and thus catecholamine synthesis and release. Since increasing brain catecholamines enhances physical performance, BCAA ingestion could lower catecholamines, reduce performance and thus negate any serotonin-linked benefit. We therefore examined in rats whether BCAA would reduce both …


Suprachiasmatic Astrocytes Modulate The Circadian Clock In Response To Tnf-Α, José M. Duhart, María Juliana Leone, Natalia Paladino, Jennifer A. Evans, Oscar Castanon-Cervantes, Alec J. Davidson, Diego A. Golombek Nov 2013

Suprachiasmatic Astrocytes Modulate The Circadian Clock In Response To Tnf-Α, José M. Duhart, María Juliana Leone, Natalia Paladino, Jennifer A. Evans, Oscar Castanon-Cervantes, Alec J. Davidson, Diego A. Golombek

Biomedical Sciences Faculty Research and Publications

The immune and the circadian systems interact in a bidirectional fashion. The master circadian oscillator, located in the suprachiasmatic nuclei (SCN) of the hypothalamus, responds to peripheral and local immune stimuli, such as proinflammatory cytokines and bacterial endotoxin. Astrocytes exert several immune functions in the CNS, and there is growing evidence that points toward a role of these cells in the regulation of circadian rhythms. The aim of this work was to assess the response of SCN astrocytes to immune stimuli, particularly to the proinflammatory cytokine TNF-α. TNF-α applied to cultures of SCN astrocytes from Per2luc knockin mice altered …


Primary Blast Traumatic Brain Injury In The Rat: Relating Diffusion Tensor Imaging And Behavior, Matthew D. Budde, Alok Shah, Michael Mccrea, William E. Cullinan, Frank A. Pintar, Brian D. Stemper Oct 2013

Primary Blast Traumatic Brain Injury In The Rat: Relating Diffusion Tensor Imaging And Behavior, Matthew D. Budde, Alok Shah, Michael Mccrea, William E. Cullinan, Frank A. Pintar, Brian D. Stemper

Biomedical Sciences Faculty Research and Publications

The incidence of traumatic brain injury (TBI) among military personnel is at its highest point in U.S. history. Experimental animal models of blast have provided a wealth of insight into blast injury. The mechanisms of neurotrauma caused by blast, however, are still under debate. Specifically, it is unclear whether the blast shockwave in the absence of head motion is sufficient to induce brain trauma. In this study, the consequences of blast injury were investigated in a rat model of primary blast TBI. Animals were exposed to blast shockwaves with peak reflected overpressures of either 100 or 450 kPa (39 and …