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Full-Text Articles in Life Sciences
Connectional Analysis Of Brain Regions Associated With Feeding, Kenichiro Negishi
Connectional Analysis Of Brain Regions Associated With Feeding, Kenichiro Negishi
Open Access Theses & Dissertations
Rodent models are invaluable for understanding the foundations of motivatedbehaviors. One major obstacle faced by these efforts is the lack of a 'wiring diagram' or a 'parts list' of structures that support motivated behaviors. Here, I present work that advances our knowledge of the structural organization of connections and chemoarchitecture of the diencephalon. Chapter 1 aims to clarify a wiring diagram of the medial prefrontal cortex (mPFC) following a recent demonstration of cortically-evoked feeding through this region. Chapter 2 clarifies the distributions of a subpopulation of tyrosine hydroxylase (TH) neurons in the hypothalamus. These disparate datasets were analyzed and interpreted …
Characterization Of Gabaergic Horizontal Cells In The Mouse Retina, Zulema Uresti
Characterization Of Gabaergic Horizontal Cells In The Mouse Retina, Zulema Uresti
Open Access Theses & Dissertations
The inner nuclear layer of the mammalian retina contains the cell bodies of the amacrine, bipolar and horizontal neurons. About 90% of the amacrine neurons are glycinergic and GABAergic and marked by the expression of the vesicular inhibitory amino acid transporter, VIAAT. By contrast, the phenotype in horizontal inhibitory neurons vary among different mammals. In the primate retina, experimental evidence suggests the absence of VIAAT and hypothesizing that GABA could be released by efflux through the GABA transporters. On the other hand, in rodents, the horizontal cells express the VIAAT and carry out vesicle-dependent GABA release. Although the retina cells …
Sex Differences In The Mechanisms That Modulate The Neurochemical Effects Of Nicotine, Kevin Uribe
Sex Differences In The Mechanisms That Modulate The Neurochemical Effects Of Nicotine, Kevin Uribe
Open Access Theses & Dissertations
Prior behavioral studies in our laboratory revealed that overexpression of the stress peptide, corticotrophin-releasing factor (CRF), in the mesocorticolimbic reward pathway enhanced the reinforcing effects of nicotine. The latter effect was greater in female versus male rats, suggesting that females are uniquely susceptible to the effects of stress on nicotine reinforcement. The goal of this dissertation was to examine the neurochemical mechanisms by which overexpression of CRF in the nucleus accumbens (NAc), a terminal region of the mesocorticolimbic pathway, modulates the behavioral effects of nicotine. Specifically, we examined whether nicotine-induced dopamine levels are altered by CRF overexpression via excitatory (glutamate) …
Imaging Live Drosophila Brain With Two-Photon Fluorescence Microscopy, Syeed Ehsan Ahmed
Imaging Live Drosophila Brain With Two-Photon Fluorescence Microscopy, Syeed Ehsan Ahmed
Open Access Theses & Dissertations
Two-photon fluorescence microscopy is an imaging technique which delivers distinct benefits for in vivo cellular and molecular imaging. Cyclic adenosine monophosphate (cAMP), a second messenger molecule, is responsible for triggering many physiological changes in neural system. However, the mechanism by which this molecule regulates responses in neuron cells is not yet clearly understood. When cAMP binds to a target protein, it changes the structure of that protein. Therefore, studying this molecular structure change with fluorescence resonance energy transfer (FRET) imaging can shed light on the cAMP functioning mechanism. FRET is a non-radiative dipole-dipole coupling which is sensitive to small distance …
Electrical Stimulation Uses Sodium Channel Dependent Depolarization To Produce Exocytotic-Like Dopamine Release And Rotational Behavior In Vivo, Alice Elaine Hernandez
Electrical Stimulation Uses Sodium Channel Dependent Depolarization To Produce Exocytotic-Like Dopamine Release And Rotational Behavior In Vivo, Alice Elaine Hernandez
Open Access Theses & Dissertations
The goal of this project was to establish Electrical Stimulation (ES) in combination with In Vivo Intracerebral Microdialysis (IVMCD) as a methodology to evoke exocytotic-like dopamine (DA) release. To provide evidence that ES mimics action potential-mediated DA exocytosis, we hypothesized that ES produces depolarization of the membrane potential that is dependent upon sodium (Na+) -channels to produce DA release concomitantly with rotational behavior. To test this, rats received electrode and cannulae implants along the medial forebrain bundle, which contains the DAergic nigrostriatal pathway, and a microdialysis probe at the striatum to undergo IVMCD testing. To begin, steady baseline DA levels …
Dopamine Regulation Of Disengagement In The Basal Ganglia Circuitry, Mabel N. Terminel
Dopamine Regulation Of Disengagement In The Basal Ganglia Circuitry, Mabel N. Terminel
Open Access Theses & Dissertations
Evidence suggests that dopamine (DA) is crucial for initiation and termination as well as sustained execution of movement. For the present study, it was hypothesized that DA plays a more important role in initiation and termination of movement than in its sustained production. To test these hypotheses, rats were trained to walk on a treadmill in a continuous and discontinuous (walk 30 secs/stop 15 seconds) fashion for one hour while striatal DA samples were collected using In Vivo Microdialysis (IVMCD). We predicted larger increases during discontinuous compared to continuous walking. It was found that brain dialysate levels of DA consistently …
Examination Of The Neurochemical Mechanisms That Mediate Nicotine Withdrawal In Adolescent And Adult Rats, Luis Alberto Natividad
Examination Of The Neurochemical Mechanisms That Mediate Nicotine Withdrawal In Adolescent And Adult Rats, Luis Alberto Natividad
Open Access Theses & Dissertations
Introduction: The mechanisms that mediate nicotine withdrawal are presently unclear and age group differences in the neurochemical effects of withdrawal have been largely unexplored. Previous studies in our laboratory demonstrated that adult rats display a decrease in extracellular levels of dopamine in the nucleus accumbens (NAcc) during nicotine withdrawal and this decrease is reduced in adolescent rats (Natividad et al., 2010). The goal of this dissertation was to examine whether these age group differences in dopamine during withdrawal are mediated via excitatory and inhibitory mechanisms that modulate dopamine in the cell body region of the ventral tegmental area (VTA). Methods: …
The Effects Of Extended Access To Methamphetamine Self-Administration On Dopaminergic Markers In The Striatum, Joe Luevano
The Effects Of Extended Access To Methamphetamine Self-Administration On Dopaminergic Markers In The Striatum, Joe Luevano
Open Access Theses & Dissertations
Methamphetamine (METH) abuse is a persistent problem in the U.S. and abroad. Escalation of METH use among independent users occurs for a variety of physiological and psychological reasons. Methamphetamine dependence may be attributed to the rewarding effect of this drug via the dopaminergic systems of the central nervous system (CNS). The presence of METH in the CNS increases synaptic release of dopamine. This increase in dopaminergic neurotransmission is thought to be directly attributed to the rewarding effects of METH. Following METH use, compensatory changes have been found to occur in the dopaminergic system during various periods of abstinence. It is …
The Role Of Dopamine In Operant Learning And Memory, Jennifer Leigh Johnson
The Role Of Dopamine In Operant Learning And Memory, Jennifer Leigh Johnson
Open Access Theses & Dissertations
Dopamine is a neurotransmitter that regulates many physiological processes including reward, motivation, movement, learning and memory, and reinforcement. The cognitive processes in which one associates a specific action or behavior with a positive or negative consequence is referred to as operant learning, and is a robust occurrence in everyday life. It is also believed to play a significant role in the development of drug addiction and has been shown that increased levels of dopamine are associated with the intake of addictive drugs such as cocaine and alcohol; however, the underlying cellular mechanisms of this learned behavior are not well understood. …
Characterization Of The Behavioral And Neurochemical Effects Of Nicotine Withdrawal In Adolescent And Adult Rats., Luis Alberto Natividad
Characterization Of The Behavioral And Neurochemical Effects Of Nicotine Withdrawal In Adolescent And Adult Rats., Luis Alberto Natividad
Open Access Theses & Dissertations
Previous studies have demonstrated that the behavioral effects of nicotine withdrawal are lower in adolescent versus adult rats. However, the neurochemical mechanisms that mediate these developmental differences are presently unclear. Much work has shown that nicotine reward is mediated via enhanced dopamine neurotransmission in the mesolimbic pathway which originates in the ventral tegmental area (VTA) and terminates in several forebrain structures including the nucleus accumbens (NAcc). More recently, studies have shown that nicotine withdrawal produces a decrease in NAcc dopamine transmission, an effect that is believed to serve as a neurochemical marker of withdrawal in adult rodents. The goal of …