Life Sciences Commons^™

The Effect Of Trimethyltin On The Cholinergic System Of The Rat Hippocampus, Richard L. Cannon

Electronic Theses and Dissertations

Trimethyltin (TMT) is a neurotoxin occurring in the environment. Exposure to (TMT) is known to destroy specific neuronal components of the hippocampus in the rat and to cause clinical symptoms in exposed humans, including mnemonic deficits, that indicate hippocampal involvement. In addition to hippocampal cell loss TMT causes significant increases in cholinergic markers such as acetylcholinesterase (AChE) stain density and choline acetyltransferase (ChAT) activity in the hippocampus of rats. However, despite these observations the effect of TMT on hippocampal cholinergic system has not been investigated in detail. The purpose of the present study was to elucidate more fully the consequences …

Identification And Characterization Of Possible Multiple Binding Sites For ((3)H)8-Oh-Dpat In The Hippocampus, Dawna Lea Evans

Masters Theses

No abstract provided.

Fixed-Ratio Size As A Determinant Of The Development Of Tolerance To Morphine, Mark J. Nickel

Masters Theses

The acute and chronic effects of morphine were examined in pigeons exposed to a multiple schedule with fixed ratio 5, 25, and 125 components. Acute exposure to morphine (0.56-10.0 mg/kg) resulted in rate reductions under each component when the dose was 1 mg/kg or higher. With chronic exposure to 5.6 mg/kg, tolerance to the rate-reducing effects of morphine was evident under each fixed ratio component. The development of tolerance was determined to some extent by fixed-ratio size, a result similar to earlier findings with cocaine.

Influence Of 2,5-Hexanedione, Acrylamide, Tri-O-Tolyl Phosphate, Leptophos And Methylmercury On Endogenous Levels Of Tryptophan, Serotonin And 5-Hydroxyindoleacetic Acid And Serotonin Turnover Rates In Rat Brain, Craig H. Farr

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several industrial and environmental chemicals cause distal and/or central neuropathy among other diverse toxic effects. Spague-Dawley derived rats were fed doses of 2,5-hexanedione, acrylamide, tri-o-tolyl phosphate, Leptophos and methylmercury via gavage. The dose levels and administration periods were established in previous experiments designed to assess clinical neuropathy using rats trained to walk on a rotorod apparatus fitted with an electrode floor. After intravenous injections of ³H-Tryptophan, whole rat brain homogenates were analyzed using liquid scintillation and spectrofluorometric techniques for levels of tryptophan, serotonin and 5-hydroxyindoleacetic acid. Serotonin turnover rates were calculated using the specific activities of tryptophan and serotonin …

Aspects Of Air Pollution, And Its Effect On The Respiratory System, Jennifer Randall

Presidential Scholars Theses (1990 – 2006)

This report centers around one of today's most prominent environmental issues-- air pollution. First, the major pollutants are defined and explained. Chloroflourocarbons, ozone, carbon monoxide, carbon dioxide, methane, sulfur dioxide, nitrogen oxides, and suspended particulate matter all receive attention.

Next, air pollution's effect on the Earth is explained. The "greenhouse effect", global warming, acid rain, and ozone depletion all have an enormous impact on Earth's climate and atmosphere.

The report proceeds on to discuss options for controlling and so lving the air pollution problem. Se+ective catalytic reduction, noncatalytic reduction, tradeable permits-- these three processes are examples of large scale attempts …

Evidence That Nicotine Can Acutely Desensitize Central Nicotinic Cholinergic Receptors In Vivo, John Randolph James

Theses and Dissertations

Current concepts concerning nicotine's central nervous system (CNS) mechanism(s) of action suggest that this drug is producing its effects via an interaction at nicotiniccholinergic receptors (nAChRs) which open a membrane cation channel. Following initial opening of the channel, nicotine appears to induce a rapid desensitization of the nAChRs, closing the channel and resulting in a cessation of nicotine's effects. Research presented here will provide evidence of this secondary desensitization process in vivo by demonstrating nicotine's ability to induce acute tolerance in the discriminative stimulus (DS) paradigm. The ability of nicotine to elicit DS control of behavior was significantly reduced via …

Central Serotonergic Stimulation Of Renin Secretion, Peter Andrew Rittenhouse

Dissertations

No abstract provided.

Pharmacological Manipulation Of Protein Kinase C Modulates The Growth And Lineage Commitment Of Enriched Human Myeloid Progenitor Cells Induced By Hematopoietic Growth Factors, Fei Li

Theses and Dissertations

The activity of protein kinase C (PK-C) has been implicated in regulating the growth and differentiation of both normal and neoplastic hematopoietic cells. We have examined the effects of the PK-C activators, phorbol 12,13- dibutyrate, mezerein, and bryostatin 1, on the proliferation and lineage commitment of enriched CD34+ human myeloid progenitor cells stimulated by lL-3, GM-CSF, stem cell factor and the lL-3/GM-CSF hybrid cytokine plXY321. Coadministration of these PK-C activators with plateau concentrations of rlL-3 or rGM-CSF induced 100-150% increase in the number of day 14 CFU-GM.with a selective stimulation on neutrophil and macrophage lineages while inhibiting eosinophilic growth. plXY321 …

Development And Standardization Of A Short-Term Assay For Evaluating Polluted Estuarine And Coastal Environments: The Medaka Embryo-Larval Assay, Michael Frederick Helmstetter

OES Theses and Dissertations

The eggs of the Japanese medaka (Oryzias latipes) were employed in a number of studies to develop a routine, standardized assay which can assess the acute and sublethal impacts of individual toxicants and complex mixtures. The eggs of this Cyprinodont minnow were topically treated with each toxicant or mixture dissolved in membrane permeable dimethylsulfoxide (DMSO) solvent. Nine chemicals were initially evaluated with two, pentachlorophenol (PCP) and tributyltin chloride (TBTCl), subsequently selected for extensive evaluations of salinity tolerance and the accuracy of the topical exposure method for representing a typical immersion exposure. The amount of material actually penetrating the eggs was …