Anatomy Commons^™

Connectivity Of Monosynaptic Ia Afferents On Renshaw Cells In Neonatal Mice, Todd Joseph Rapetti

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Proprioception allows sensory information about muscle position and length to enter the CNS without the aid of visual cues. One type of fiber that carries this information is the Ia afferent, which innervates muscle spindles that respond to mechanical perturbation in muscle. Ia fibers are known to synapse with Ia interneurons (INs) and motor neurons (MNs), setting up important circuits which affect movement. Another type of IN is the Renshaw cell (RC), which is located in the ventral part of lamina VII of the spinal cord and is critical for the functionality of the recurrent inhibitory circuit. In addition to …

Effects Of Delayed Pharmacological Treatment And Limb Rehabilitation On Infarct Size And Functional Recovery After Stroke, Maria Helen Harley Balch

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Previous studies show a fluoxetine/simvastatin drug combination successfully reduced infarct size and increased functional recovery when administered 20-26 hours post stroke. This project tested the hypothesis that earlier drug delivery at 6-12 hours post stroke will improve functional recovery and decrease infarct size, and that limb rehabilitation will improve functional recovery.

Pre-stroke function was determined in rats, a stroke was induced, and daily treatment began 6-12 hours post stroke. Baseline functional deficit was established, and additional testing over 90 days monitored functional recovery. Limb rehabilitation was provided for designated animals, and brain analysis measured infarct size.

In animals with no …

The Interaction Between Atp13a2 And Alpha-Synuclein In Mice, Emily Ribak Dirr

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Abnormal accumulation of the presynaptic protein alpha-synuclein (aSyn) is associated with both familial and sporadic forms of Parkinson's disease. ATP13A2 is a lysosomal protein involved in protein degradation, including aSyn. Mice with a loss of ATP13A2 function develop age-related sensorimotor impairments and, in the brain, enhanced lipofuscin and insoluble aSyn accumulation. To further examine the potential interaction between aSyn and ATP13A2, aSyn overexpressing mice (aSyn) were crossbred with Atp13a2-defeicient (13a2) mice. Wildtype (WT), 13a2, aSyn, and double mutant aSyn/13a2 mice were generated and tested behaviorally at 3 ages. Sensorimotor function and cognition were examined using a battery of behavioral tests. …

Ia Afferent Connectivity With Glycinergic Interneurons In Early Postnatal Mice, Brenna Colleen Gosky

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In animals proprioceptive Ia afferents enable the animal to sense the location, orientation and movement of its limbs in space. These Ia afferents make connections with many different types of neurons within the spinal cord such as; motor neurons, Ia Inhibitory interneurons, and other interneurons. Ia Afferents connect with IaINs that project to antagonist muscle MNs to ensure that contraction of the antagonist muscle group is inhibited. For example the quadriceps Ia afferents contact IaINs that contact PBST motor neurons to inhibit excitation and thus contraction. The way in which the connectivity of these Ia afferents is established is not …

C-Bouton Coverage Of Alpha-Motoneurons Following Peripheral Nerve Injury, Esra Salah Shermadou

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Peripheral nerve injuries (PNI) cause alternations in central synapses leading to loss of function. The C-bouton synapses onto a-motoneurons in the ventral horn, and has a role in regulating motor output. Following tibial nerve ligation, the somatic C-bouton coverage is depleted (Alvarez et al., 2011), however, it is unknown what happens following crush type injuries. PNI causes neuroglia activation and proliferation that contribute to synaptic alterations, a response that has not been well-characterized in the ventral horn, where motoneurons are located. Therefore, I hypothesize that glia activation following peripheral nerve injury correlates to the degree of depletion of synaptic coverage …

Effect Of Rat Strain Stereotactic Coordinates On Infarct Volume, Saagar K. Sanghvi

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Ischemic stroke makes up 87% of all hospital-admitted stroke cases annually; the primary treatment for these cases is intravenous administration of tPA within a 3.5 hour window from stroke onset. A long-term delayed ischemic stroke treatment proposed by this study was a combination of the pharmaceuticals Fluoxetine (SSRI), Simvastatin (statin), and ascorbic acid (Vitamin C). 51 adult rat subjects (10-12 months of age; 44 Sprague Dawley, 7 Long Evans) were given a combination of the drugs for 31 days. Drugs were given through voluntary oral administration via sugar cookie-dough balls to reduce inhibition of neurogenesis through stress-related glucocorticoid production. Drug …

Characterization Of Stimulation-Induced Volume Changes In The Ca1 Region Of Rat Hippocampus Slices, Amanda Brooke Gutwein

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Intrinsic optical signals (IOS) were used to evaluate volume regulation mechanisms during Schaffer collateral stimulation-induced volume changes in hippocampal slices. The effects of stimulation frequency, synaptic function, ionotropic glutamate receptor (iGluR) activation, glutamate uptake, and volume regulatory anion channels (VRAC) were examined with IOS. Data were analyzed using ANOVA with Dunnett's post hoc test (p<0.05 indicated significance). IOS changes were stimulation frequency dependent between 1 Hz and 10 Hz with full recovery of IOS within 5 min. Synaptic blockage reduced the rate of swelling by 81% compared to the control and the IOS did not fully recover. Recovery rate was reduced with iGluR inhibition. Inhibition of glutamate uptake reduced the rate of swelling by 70% compared to vehicle controls. During stimulation, action potentials, iGluR activation, and glutamate uptake contribute to swelling. Regulatory volume mechanisms during stimulation were glutamate-mediated via iGluRs and VRAC independent.

The Role Of Corticotropin-Releasing Factor In The Behavior And Proinflammatory Activity Of Separated Guinea Pig Pups, Vincent Rasahd Alexander

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Isolation of guinea pig pups in a novel environment first produces active behaviors such as vocalizing and movement; over time, these behaviors wane and pups show characteristic passive responses similar to those produced by increased proinflammatory activity. Further, isolation of pups on two consecutive days has recently been shown to enhance those passive responses on the second day. Endogenous proinflammatory activity is thought to mediate the enhancement (sensitization). An injection of corticotropin-releasing factor (CRF) has been shown to increase passive behavior, possibly by increasing proinflammatory activity. The present study further investigated the role of CRF on proinflammatory activity and behavior …

Maturation Of The Carotid Body Oxygen-Sensor During Rat Development, Julia Paulet

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Carotid bodies (CB) are paired, oxygen-sensing organs located in the bifurcation of the carotid artery that act as peripheral chemoreceptors in the detection of hypoxic, hypercapnic and acidotic levels in the arterial blood. CBs respond to these fluctuations in blood gases by initiating firing of the carotid sinus nerve. This ultimately results in the appropriate ventilatory change to restore blood gases to their physiological levels. Studies have shown that the hypoxic response of the carotid body in juvenile mammals is low, but as maturation occurs this response is strengthened and clearly exhibited in adults. One theory suggests mitochondria play a …

Effects Of Elevated Glucocorticoid Levels On Dentate Gyrus Development, Zachary Dale Vallandingham

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Exogenous glucocorticoids are commonly used in modern medications and animal studies examining the effects of glucocorticoids on the developing brain report inconsistent results. Recent reports have questioned the reliability of available drug delivery methods in mice (Herrmann et al., 2009). In our laboratory, variable behavioral results using trace eyeblink conditioning (EBC) suggest that we may be having similar problems delivering glucoroticoids to developing rat pups (Claflin et al., 2005, 2011). Subcutaneous pellets and osmotic minipumps resulted in impaired learning during trace eyeblink conditioning whereas subcutaneous injection of corticosterone (CORT) resulted in facilitation of learning on the same task. One of …

Electrical Brain Stimulation And Depressive-Like Behavior In Guinea Pigs, Nadia Kardegar

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Maternal separation in guinea pigs produces a biphasic response consisting of an active behavior phase (vocalizations and locomotor activity) followed by a phase of passive depressive-like behavior (crouched stance, piloerection, and eye closure). The mechanism for the transition from the active to the passive phase is unknown. One suggestion is that continual activity of neural circuitry producing active behavior eventually leads to the expression of passive behaviors. The purpose of this study was to test this possibility. Guinea pigs were assigned to experimental and control groups. The experimental group received daily stimulation of the bed nucleus stria terminalis (BNST) to …

Influence Of Daily Electrical Stimulation Of Periaqueductal Grey On Vocalization And Depressive-Like Behavior During Separation In Guinea Pigs, Jennifer Dazey

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Maternal separation has been shown to promote the onset of depression. This early life stressor produces a biphasic response marked by an active "protest" phase followed by a passive "despair" phase in humans as well as several other species. In infant guinea pigs, active phase behaviors include increased locomotion and species-typical distress vocalizations, whereas the passive phase is marked by depressive-like behaviors including a crouched stance, eye-closure and extensive piloerection. The mechanism underlying the transition from one phase to the next is still unknown. The purpose of this study was to determine if daily stimulation of the neural pathway initiating …

Glutamate Receptor-Mediated Taurine Release From The Hippocampus During Oxidative Stress, Brian Christopher Tucker

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Oxidative stress is an important result of cerebral ischemia and has been directly linked to hippocampal swelling and cytotoxic brain edema in vitro. Swollen brain cells activate volume regulatory mechanisms including a significant efflux of the endogenous sulfonic amino acid taurine via volume-regulated anion channels (VRACs). Studies in brain slice preparations also suggest that the excitatory amino acid glutamate plays an important role in both brain tissue swelling and in cell volume regulation. We examined relationships between oxidative stress, glutamate receptor activation, cell swelling, and volume regulation in acutely prepared slices of rat hippocampus. Our results indicate that the release …

Persisiting Sensitization Of Depressive-Like Behavior And Thermogenic Response During Maternal Separation In Pre- And Post Weaning Guinea Pigs, Randi Lynn Schneider

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Early attachment disruption is thought to promote later onset of depressive illness through a process involving sensitization. Maternal separation in guinea pig pups (~21 days of age) produces depressive-like behavior and core body temperature fluctuations that appear to be mediated by proinflammatory activity. These responses are enhanced during repeated separations over several days. Here, enhanced depressive-like behavior and core body temperature responses were observed from the early pre-weaning to the periadolescent period (~10-40 days of age) and persisted for more than a week. The greatest temperature response was observed during the final separation. These results demonstrate persisting sensitization of behavioral …

Aquaporin 4 Expression And Distribution During Osmotic Brain Edema And Following Chronic Treatment Of Desipramine, Sergei Alexander Robinson

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Osmotic brain edema or chronic treatment with desipramine alters brain water permeability. In this study we investigated aquaporin 4 expression and distribution in these two conditions. Brain edema development was induced by intraperitoneal water injection. Blood serum osmolality decreased from 296 ± 1 mOsm to 278 ± 2 mOsm within 15 min. Cerebral cortex water content increased from 79.8 ± 0.2 % to 81.3 ± 0.5% during 120 min of this hyposmotic exposure. Aquaporin 4 immunostaining intensity at the astrocytic endfeet increased in water injected animals from 2.6 ± 0.04 intensity unites (IU) to 3.2 ± 0.21 IU, while total …

Sensitization Of Behavioral Response To Maternal Separation: Persistence Of The Effect And Role Of Proinflammatory Activity, Jessie Caraway

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Maternal separation in guinea pigs produces a biphasic response consisting of an active behavior phase followed by a phase of passive behavior (crouched stance, piloerection, and eye closure). Previous studies suggest that pro-inflammatory cytokines mediate passive behavior during the passive phase. It is also known that guinea pig pups separated on two consecutive days show a significant increase (sensitization) in full passive behavior on the second day. The current study examined the persistence and role of pro-inflammatory activity in the sensitization of passive behavior in maternally separated guinea pigs. Guinea pig pups were assigned to one of four groups differing …

The Role Of Apoptosis In Hela Cells Expressing Hiv-1 Rev, Elizabeth Page

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The HIV protein Rev is a nucleolar protein that regulates late gene expression in infected cells by promoting the export of under-spliced viral RNAs (Pollard and Malim, 1998). Its over-expression can also inhibit progression through mitosis (Miyazaki et al., 1995), possibly through its ability to depolymerize microtubules (Watts et al., 2000). Consequently, Rev may activate the spindle assembly checkpoint in mitotic cells and increase the frequency of apoptosis. Rev also binds the nucleolar protein B23 involved in ribosome maturation and centrosome duplication. Because loss of B23 function stimulates apoptosis (Ahn et al., 2005), Rev expression may promote apoptosis by inhibiting …

Short-Term Administration Of Corticosterone Has Lasting Effects On Learning In Young Rats, Christine L. Wentworth-Eidsaune

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Corticosterone is a glucocorticoid released as part of the body's response to stress and is known to affect cognitive function, presumably via effects on the hippocampus. Trace classical eyeblink conditioning depends on the hippocampus, and has been used to examine the development of learning processes in young organisms. Experiment 1 was a dosing study, in which time course of effect of corticosterone was followed in 15-day-old Long-Evans rat pups over 24 hours for 4 different concentrations (high: 0.02 mg/g body weight (b.w.), medium: 0.01mg/g b.w., low: 0.005 mg/g b.w. and a vehicle control). In Experiment 2, two subcutaneous injections (0.02 …

Developmental Expression Of Calcium Buffering Proteins In Central Auditory Pathways Of Normal Hearing And Congenitally Deaf Mice, Adam S. Deardorff

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These experiments analyze differences in synaptic development in central auditory pathways between normal hearing (CBA/J) and congenitally deaf (dn/dn) mice, which provide valuable insight into central synaptic plasticity corresponding to human congenital deafness. Immunofluorescent analysis of the developmental expression of the calcium buffering proteins calretinin, calbindin d-28k, and parvalbumin at various postnatal time points was performed to assess the effects of altered neural activity on the level and/or pattern of protein expression within these nuclei. Results indicate that the pattern of calbindin and parvalbumin is unaffected by congenital deafness in dn/dn mice. However, the pattern of calretinin expression in the …

Presynaptic Regulation Of Carotid Body Type I Cells By Histaminergic And Muscarinic Receptors, Carrie Marie Thompson

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Type I cells are one of two main cell types located within the carotid body. These cells respond to hypoxia, hypercapnia, and acidosis by releasing excitatory and inhibitory neurotransmitters. This causes increased firing of the carotid sinus nerve and restores blood gas levels to their physiological values. While previous studies have shown whether individual neurotransmitters are excitatory or inhibitory, this work demonstrates how the interplay between two neurotransmitters may potentially shape the output of the carotid body. Histamine, which has previously been shown to have no effect on intracellular Ca2+ in type I cells, may function to modulate the actions …

The Presynaptic Regulation Of Isolated Neonatal Rat Carotid Body Type I Cells By Histamine, Drew C. Burlon

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It has been previously shown that Carotid Body Type I cells have the ability to synthesize, package and release histamine in response to hypoxia, thereby contributing to the modulation of respiration within the rat. Here, isolated neonatal rat carotid body type I cells were used to identify the presynaptic effects of histamine and the specific receptor subtypes that modulate them. Although all four histamine receptor subtypes are expressed on the type I cells, and preliminary data showed promising results, further data proved that the activation of these receptors with histamine or selective agonists caused no rise in intracellular calcium ([Ca2+]i) …

Reorganization Of Ia Afferent Synapses On Motoneurons After Peripheral Nerve Injuries, Haley E. Titus

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After peripheral nerve injuries patients lose and do not recover the stretch reflex which leads to altered locomotor function. The focus of this thesis is to investigate the structural integrity of the central connection between Ia afferents and alpha motoneurons that mediate the stretch reflex. The overall hypothesis is that the density and distribution of Ia synapses on motoneurons is altered after peripheral nerve injuries. Analysis of Ia afferent-motoneuron contacts, revealed by vesicular glutamate transporter 1 (VGLUT1) immunoreactivity, on the soma and dendritic arbor of motoneurons after peripheral nerve injuries revealed major reorganizations in the distribution and density of Ia …

Inhibition Of Pro-Inflammatory Processes Reduces Sensitization Of The Behavioral Response To Maternal Separation, Kristopher Doojin Paik

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The current study examined the behavioral sensitization of guinea pig pups in response to consecutive days of maternal separation. In the first experiment, guinea pigs that received centrally administered artificial cerebrospinal fluid or IL-10 exhibited sensitization of passive behaviors from Day 1 to Day 2. IL-10 decreased the levels of passive behaviors on Day 1, as well as the increase on Day 2. The second experiment used unoperated pups, which also showed sensitization of the passive response from Day 1 to Day 2, though the effect appeared reduced relative to control pups of Experiment 1. Collectively, this investigation confirms previous …

Effects Of Sepsis On Nerve Evoked Responses, Kevin Richard Novak

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Sepsis and SIRS (systemic inflammatory response syndrome) have become two expensive and complicated problems seen in the intensive care unit (ICU). These two illnesses have been known to cause dysfunction with excitable tissues in the body. Encephalopathy, neuropathy, and myopathy are the three biggest. In this paper we discuss the development of an animal model of sepsis and the neurological complications sepsis brought about. Nerve conduction studies showed increased durations on compound muscle action potential, and decreased amplitude as well as increased duration and latency on sensory nerve action potentials. These results were not consistent with the two most common …

Oxidative Stress And Cell Death In Osmotically Swollen Glial Cells, Crystal Elaine Stuckey

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Regulation of normal volume is an important aspect of cell homeostasis. Possible mechanisms which signal volume regulation are increasing the rate of reactive oxygen species (ROS) production and release of ATP for interaction with purinergic receptors. We examined whether an increase in ROS production during cell swelling also led to cell injury of C6 glioma cells. Cells were loaded with 5,6-carboxy-2,7-dihydrofluorscein diacetate (DCFDA) to fluoroscopically measure the rate of cellular ROS production and were perfused with phosphate-buffered saline solutions (PBS) containing 100 μM carbenoxolone to inhibit dye efflux. Cell death was determined cytometrically and by measuring the release of lactate …

Effects Of Subcutaneous Postnatal Choline Supplementation On Hippocampus-Mediated Learning And Memory In Rat Pups, Jeremy Alan Moore

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The effects of postnatal injections of choline on the acquisition of two variants of eyeblink conditioning were examined in developing Long-Evans rat pups. Choline administration on postnatal days (PND) 15-27 was followed by evaluation of trace eyeblink conditioning (Experiment 1) and delay eyeblink conditioning (Experiment 2) on PND 28-29. The results of these experiments show that choline produced greater improvements in learning and memory during the trace condition than in the delay condition, presumably due to its effect on the hippocampus. Trace eyeblink conditioning relies heavily on an intact hippocampus but delay eyeblink conditioning does not, and it is understood …

Stress Reducing Effects Of Oxytocin In A Maternal Separation Paradigm, Keely Jane O'Connell

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This study compared the effects of centrally and peripherally administered oxytocin (OT) on HPA axis activity and the presence of both stress-induced active and passive behaviors in female guinea pig pups (Cavia porcellus) after 180-min of isolation . In Experiment 1, one dose of oxytocin (10μg/.2ml) was injected subcutaneously into the periphery. Plasma cortisol levels were reduced after 180-min of isolation and two passive behaviors, eye-closure and crouch, were reduced as well with the administration of oxytocin. In Experiment 2, two different doses (10μg/.2ml and 20μg/.2ml) were injected into the periphery with no significant results. In Experiment 3 one dose …

The Development And Molecular Expression In Mammalian Cells Of An Ha-Tagged Plasmid Encoding For The Target Of Rapamycin (Mtor), Kevin S. Dougherty

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The protein kinase mammalian Target of Rapamycin (mTOR) is a master controller of cell growth and proliferation due to its ability to integrate growth signals and regulate translation through 4E-BP1 and p70-S6K. We developed four phCMV2-HA-tagged plasmids to overexpress TOR in mammalian cells: Wild Type, D2357E (Kinase Dead), R2109A (PA Binding Deficient) and, S2035T (Rapamycin Resistant) each verified by restriction enzyme digestion and direct sequencing. Plasmid DNA was overexpressed in COS-7 cells and the 289 kDa protein detected in Western blots developed with anti-HA and anti-mTOR antibodies. Kinase activity of the overexpressed protein was detected by in vitro phosphorylation of …

Developmental Expression Of Calcium-Binding Proteins In The Avcn And Mntb Of Normal Hearing And Congenitally Deaf Mice, John L. Roebel

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This experiment analyzes synaptic differences in the central auditory pathway between normal hearing and congenitally deaf (dn/dn) mice, and provides valuable insight into central changes that correspond with human congenital deafness. Specifically, this experiment analyzes developmental expression of the Calcium (Ca2+)-binding proteins Calretinin (CR), Calbindin D-28k (CB) and Parvalbumin (PV) in large excitatory synapses in the anteroventral cochlear nucleus (AVCN) and the medial nucleus of the trapezoid body (MNTB) of normal and dn/dn mice. Immunofluorescence imaging with primary antibodies detecting CR, CB or PV was used to analyze the expression of each at 9 days, 13 days, 20 days, 30 …

The Relationship Between Lactic Acid, Reactive Oxygen Species And The Hypoxia-Induced Acidification Seen In Chemosensitive Neurons Of The Nucleus Tractus Solitarius (Nts), Trevor Downing

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The NTS is one of many sites of chemoreception meaning that it responds to changes in CO2 and pH. NTS neurons also acidify approximately 0.13 pH units in response to hypoxia. Experiments involved brainstem slices exposed to a control hypoxic bout followed by hypoxia in conjunction with different drugs. The drugs included fluorocitrate, 4-hydroxycinnamate, oxygen-glucose deprivation and iodoacetate. Iodoacetate produced the strongest blunting of the hypoxia-induced acidification and decreased the response by ~53%. Results from the studies using the superoxide probe DHE showed an increase in the levels of ROS during the hypoxic exposure prior to reoxygenation. Two ROS scavengers …