Medicine and Health Sciences 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 …

The Inhibitory Effects Of Opioids On Voltage-Gated Calcium Influx In Neonatal Rat Carotid Body Type I Cells, Ellen M. Ricker

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It is known that opioids inhibit the hypoxic ventilatory response, but little is known about the mechanisms that underpin this. This study's objectives were to examine which opioid receptors are located on the oxygen-sensing carotid body type I cells and determine whether selective agonists inhibit cellular excitability.

Immunocytochemistry revealed the presence of μ and κ opioid receptors on type I cells. The μ-selective agonist DAMGO (10μM) and the κ-selective agonist U50-488 (10μM) significantly (p<0.0025 and p<0.0095 respectively, unpaired student's t-test) inhibited high K+ induced rises in intracellular Ca2+ compared with controls. After a three-hour incubation with pertussis toxin, a Gi protein-coupled inhibitor, DAMGO and U50-488 (10μM) has no significant effect on the responses to K+.

These results indicate that opioids acting at μ and κ receptors inhibit voltage-gated Ca2+ influx in carotid body type I cells. This mechanism may explain, in …

Angiotensin-Ii Receptor Blocker And Its Effects On Depressive-Like Behavior During Maternal Separation, Evan D. Xanthos

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Maternal separation has been shown to promote the onset of adult depression. This early life stressor produces a biphasic response marked by an active "protest" phase followed by a passive "despair" phase in humans and other species. In infant guinea pigs, active phase behaviors include increased locomotion and distress vocalizations, whereas the passive phase is marked by depressive-like behaviors including a crouch stance, eye closure and piloerection. Separation elicits physiological responses including increased core body temperature and proinflammatory cytokine expression suggesting fever. Angiotensin-II receptor blockers (ARB's) inhibit inflammation both peripherally and centrally following peripheral administration. The goal of the present …

Is Polyvinylidene Diflouride (Pvdf) Film Biocompatible In The Murine Cochlea?, Robert Maxwell Jaggers

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Polyvinylidene fluoride (PVDF) film, a biomaterial that is an integral part of a Totally Implantable Sustainable Hearing Aide (TISHA) device, was examined to determine its biocompatibility within the murine cochlea. The biofilm was implanted in the ear using a round window cochleostomy in 7-9 week old male C57BL/6 mice. Three test groups containing seven mice each were implanted with PVDF film. Each mouse received a sham surgery on the non-implanted cochlea. Three test groups were examined at 48 hours, 3 weeks, and 3 months. At the end of this time the mouse was euthanized, the tissue containing the cochlea was …

Efficacy Of Mastery-Based And Autonomy-Supportive Neuroanatomy Curriculum In Graduate Level Human Neurobiology Course, Corin Wolfgang Magee

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Anatomy provides scientists with a common vocabulary for discussing the human body, and is, therefore, an important aspect of science education. Literature shows that traditional teaching methods may be enhanced by the employment of mastery-based learning in an autonomy-supportive environment. The present study sought to determine the effects of these teaching strategies on the learning of neuroanatomy in a graduate neurobiology course.

These results show students learned and reportedly enjoyed learning a large amount of neuroanatomy. Experimentally taught students who completed the curriculum did well on the 30-item neuroanatomy quiz (mean score 81%), which was administered at the end of …

Mechanisms Of Hyperglycemia-Induced Ros Production In Osmotically Swollen Glial Cells, Augusta K. Eduafo

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Cerebral edema is a potentially fatal complication of diabetes. There is evidence for increased Reactive Oxidative Species (ROS) production during cerebral edema in diabetics. This can lead to oxidative stress, thought to contribute to the onset and progression of diabetes and can cause cell injury and cell death. ROS, in moderate amounts, are involved in physiological processes within the body that produce favorable cellular responses. Unfortunately, high levels of ROS can lead to cellular damage of lipids, membranes, proteins and DNA. Hyperglycemia can cause an increase in ROS production due to activation of NADPH oxidases. The purpose of this study …