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The Influence Of Sustained Cb1 Blockade During Adolescence On Breakpoints In A Progressive-Ratio Paradigm, Mayo Jerry Wright Jr. Jan 2006

The Influence Of Sustained Cb1 Blockade During Adolescence On Breakpoints In A Progressive-Ratio Paradigm, Mayo Jerry Wright Jr.

Theses and Dissertations

The developmental psychopharmacology of cannabinoids is poorly understood and little is known about the developmental consequences of repeated exposure to cannabinoid antagonists. In these experiments, male Long-Evans rats were treated with SR141716A, a cannabinoid antagonist, throughout adolescence and allowed unrestricted access to food. Control groups were treated with vehicle during the same developmental period and allowed either unrestricted access to food or were pair-fed with a member of the SR-treated group. Motivation to work for food was measured in progressive-ratio sessions at varying levels of food deprivation. For rats that consumed fewer calories throughout adolescence, whether because of pharmacological intervention …


Influence Of The Vitamin D3 Analog Eb 1089 On Senescence And Cell Death Pathways In The Response Of Breast Tumor Cells To Ionizing Radiation, Gerald Alan Demasters Jan 2006

Influence Of The Vitamin D3 Analog Eb 1089 On Senescence And Cell Death Pathways In The Response Of Breast Tumor Cells To Ionizing Radiation, Gerald Alan Demasters

Theses and Dissertations

A senescence-like growth arrest succeeded by rapid recovery of proliferative capacity is observed in MCF-7 breast tumor cells exposed to fractionated radiation (5 x 2Gy) alone. Exposure to the vitamin D3 analog EB 1089 (100nM) prior to irradiation converts the initial growth arrest response to cell death in part through the inhibition of radiation-induced senescence and promotion of both apoptotic and autophagic cell death. More importantly, EB 1089 was shown to profoundly reduce the rate of recovery following fractionated irradiation. The effect of EB 1089 on the temporal response to radiation is also observed in MCF-7 cells expressing caspase 3, …


Single Nucleotide Polymorphisms In The Folypoly-Gamma-Glutamate Synthetase Gene, Nadine Thompson Jan 2006

Single Nucleotide Polymorphisms In The Folypoly-Gamma-Glutamate Synthetase Gene, Nadine Thompson

Theses and Dissertations

Folic acid is an essential vitamin utilized in the one-carbon metabolism pathway for the synthesis of purine and thymidine nucleotides, which are necessary for cell growth and proliferation. As a result, the enzymes that participate in the metabolism of folic acid have been good targets for cancer chemotherapy. Folylpoly-γ-glutamate synthetase (FPGS) is an enzyme in the folate metabolism pathway that catalyzes the addition of glutamic acid to the naturally occurring folates, thereby allowing the retention of folate cofactors in cells. Similarly, in the case of cancer chemotherapy, antifolates, such as Lometrexol and Tomudex are retained in cells through the activity …


Action Of Tyrosyl Dna Phosphodiesterase On 3'-Phosphoglycolate Terminated Dna Strand Breaks, Haritha Tatavarthi Jan 2006

Action Of Tyrosyl Dna Phosphodiesterase On 3'-Phosphoglycolate Terminated Dna Strand Breaks, Haritha Tatavarthi

Theses and Dissertations

Free radical-mediated DNA double strand breaks (DSBs) are induced either directly by ionizing radiation or by certain chemicals like bleomycin. These breaks are terminated by 3'-PG (PO4CH2COOˉ) or 3'-phosphate groups formed as a result of fragmentation of deoxyribose. To study the nature of repair of these 3'-blocked breaks, we constructed substrates mimicking free-radical induced DSBs. Human and yeast tyrosyl DNA-phosphodiesterase (Tdpl) efficiently processed substrates with 3'-PGs, in either the presence or absence of magnesium, to give a 3'-phosphate. Gel filtration chromatography and western blotting codmed that the putative enzyme in human extracts that efficiently processed PG was indeed tyrosyl DNA-phosphodiesterase. …


Pathological Upregulation Of A Calcium-Stimulated Phosphatase, Calcineurin, In Two Models Of Neuronal Injury, Jonathan Elledge Kurz Jan 2006

Pathological Upregulation Of A Calcium-Stimulated Phosphatase, Calcineurin, In Two Models Of Neuronal Injury, Jonathan Elledge Kurz

Theses and Dissertations

Excitotoxic calcium influx and activation of calcium-regulated systems is a common event in several types of neuronal injury. This mechanism has been the focus of intense research, with the hope that a more complete understanding of how neuronal injury affects calcium-regulated systems will provide effective treatment options. This study examines one such calcium-stimulated enzyme, calcineurin, in the context of two common neurological pathologies, status epilepticus and traumatic brain injury.Status epilepticus was induced by pilocarpine injection. NMDA-dependent increases in calcineurin activity were observed in cortical and hippocampal homogenates. Upon closer examination, the most profound increases in activity were found to be …


The Role Of Gonadal Hormones On Opioid Receptor Protein Density In Arthritic Rats, Matthew Kren Jan 2006

The Role Of Gonadal Hormones On Opioid Receptor Protein Density In Arthritic Rats, Matthew Kren

Theses and Dissertations

The majority of research on the endogenous opioid system has focused on various pain assays and the efficacy of different opioid agonists. However, minimal attention has been focused on the effects of gonadal hormones and their impact on the opioid peptide system. The present study was designed to determine the effects of modulation of gonadal hormones on the opioid receptor protein levels in Complete Freund's Adjuvant (CFA)-treated arthritic and non-arthritic male and female Lewis rats. Midbrain and spinal cord tissues were collected for comparison of the μ, δ, and κ receptor protein levels in arthritic and non-arthritic animals. Male gonadectomy …


Immunotoxicological Evaluation Of Critical Windows Of Development Following Exposure To 1,2:5,6 Dibenzanthracene In B6c3f1 Mice, Denise Marie Hernandez Jan 2006

Immunotoxicological Evaluation Of Critical Windows Of Development Following Exposure To 1,2:5,6 Dibenzanthracene In B6c3f1 Mice, Denise Marie Hernandez

Theses and Dissertations

Numerous findings have suggested that the increased prevalence of childhood illnesses such as cancer, infection, and allergy may be due to environmental exposures. One such cause may be maternal smoking or passive smoke exposure. Known immunotoxicants in cigarette smoke and environmental pollution include polycyclic aromatic hydrocarbons such as 1,2:5,6 Dibenzanthracene (DBA). The objective of these studies was to evaluate the immunosuppressive effects of DBA on various stages of immune system development. Adult mice were administered DBA daily in corn oil at dose levels of 158, 500, 1580, and 5000 µglkg S.C. for 28 days. Immunosuppression was not observed at levels …


Glutamate Excitotoxicty Activates A Novel Calcium Permeable Ion Channel In Cultured Hippocampal Neurons, Laxmikant Sudhir Deshpande Jan 2006

Glutamate Excitotoxicty Activates A Novel Calcium Permeable Ion Channel In Cultured Hippocampal Neurons, Laxmikant Sudhir Deshpande

Theses and Dissertations

Glutamate excitotoxicity is the predominant mechanism implicated in neuronal cell death associated with neurological disorders such as stroke, epilepsy, traumatic brain injury and ALS. Excessive stimulation of NMDA subtypes of glutamate receptors leads to protracted intracellular calcium elevations triggering calcium mediated neurotoxic mechanisms culminating in delayed neuronal cell death. In addition, glutamate excitotoxicity induces a NMDA dependent extended neuronal depolarization mediated by continuous calcium influx that correlates with delayed neuronal death. Attempts to prevent neuronal death by blocking calcium entry into the neurons using calcium channel blockers or NMDA receptor antagonists have failed to provide any beneficial effects in clinical …


Relationship Between Cb1 And S1p Receptors In The Central Nervous System, Lauren Michele Collier Jan 2006

Relationship Between Cb1 And S1p Receptors In The Central Nervous System, Lauren Michele Collier

Theses and Dissertations

There is significant sequence homology and anatomical co-distribution between cannabinoid (CB1) and sphingosine-1-phosphate (S1P) receptors in the CNS, but potential functional relationships between these lysolipid receptors have not been examined. Therefore, to investigate possible relationships between these two systems at the level of G-protein activation, agonist-stimulated [35S]GTPγS binding and autoradiography were conducted. Autoradiographic studies were first performed to localize receptor-mediated G-protein activation in mouse brain. Coronal brain slices were processed for stimulation of [35S]GTPγS binding using the synthetic cannabinoid agonist WIN 55,212-2 (WIN) or SIP. High levels of WIN- and S1P-stimulated [35S]GTPγS binding were observed in the caudate putamen, hippocampus, …