Matching Items (22)
Filtering by
Description
The purpose of the present study was to investigate seasonal changes in cell proliferation in the brains of adult American bullfrog. Our main question was whether there are seasonal differences in the proliferation and/or differentiation of newborn brain cells into arginine vasotocin- (AVT) or gonadotropin releasing hormone- (GnRH) producing neurons that might regulate bullfrog reproduction. . Bullfrogs in four distinct seasonal groups received injections of bromodeoxyuridine (BrdU), a thymidine analog that is taken up by dividing cells, and then euthanized six weeks later. Using doubleimmunofluorescence procedures to visualize BrdU and AVT or GnRH, we found no evidence for newborn AVT- or GnRH-ergic cells, but observed newborn cells in close proximity to AVT and GnRH cells. My project was a follow-up study to explore seasonal changes in adult cytogenesis related to AVT and GnRH terminal fields. GnRH fiber density fluctuated seasonally in the rostral pre-optic area (RPOA) and lateral septum (LS), and newborn cell numbers changed seasonally in the amygdala (AM) and RPOA. Seasonal differences in plasma testosterone concentrations were negatively related to GnRH fiber density in the LS. These results reinforce the seasonality of reproductive signaling and adult cytogenesis and support a role for seasonal steroid-peptide hormone interactions in modulating GnRH levels. Our results suggest a relationship between seasonal adult cytogenesis and reproduction, and set the stage for further research into the nature of this relationship.
ContributorsFehr, Tristan (Author) / Orchinik, Miles (Thesis director) / Deviche, Pierre (Committee member) / Talboom, Joshua (Committee member) / Barrett, The Honors College (Contributor)
Created2013-05
Description
There has long been a link tied between obesity and such pathological conditions as nonalcoholic fatty liver disease and type two diabetes. Studies have shown that feeding rats a diet high in fat results in hepatic steatosis and steatohepatitis. Using a novel short term diet of six weeks with male adolescent Sprague-Dawley rats, our laboratory sought to investigate the early effects of high fat intake on the liver. Prior findings in our laboratory found that a high fat diet (HFD) leads to nonalcoholic fatty liver disease as well as other symptoms of metabolic syndrome. This study hypothesized that rats fed a 60% HFD for 6 weeks, unlike a high sucrose or standard chow diet, would have an elevated expression of pro-inflammatory cytokines associated with steatohepatitis. TNF-α, TLR4 and XBP1 were chosen for their link to hepatic inflammation. The results of this study found that contrary to the hypothesis, the high fat diet did not induce significant changes in the expression of any inflammatory marker in comparison to a high sucrose or control chow diet.
ContributorsCalhoun, Matthew (Author) / Sweazea, Karen (Thesis director) / Deviche, Pierre (Reviewer) / Barrett, The Honors College (Contributor)
Created2015-05
Description
Research suggests that the more positive the first drug experience, the more likely addiction will develop. Since smoking is initiated in a social setting, it is surprising how little is known about social context effects on acquisition of nicotine self-administration. We investigated this issue in rats during late adolescence using conjoined self-administration chambers that had a removable shared wall. Rats were assigned to training conditions with either a solid black plexiglass or wire mesh partition in place throughout 22 subsequent 2-hour daily training sessions. Initially, 58 day-old (late-adolescent) male and female rats received 2, 30-min habituation sessions/day over 2 consecutive days, with only an inactive lever present. Sessions began with presentation of a retractable lever and thereafter each response on that lever resulted in simultaneous delivery of saline or 1 of 2 doses of nicotine (0.015 or 0.030 mg/kg, IV) and lever retraction for a 20-second time out. The findings indicate that the social context inhibits nicotine self-administration in female rats during the development of addiction, but has little effect on the initial stages of drug acquisition. Furthermore, the data suggest that in male rats the social context enhances responding independent of nicotine, but has few effects on nicotine self-administration during the development of addiction. The findings have important implications for substance use disorders.
ContributorsDufwenberg, Martin (Author) / Neisewander, Janet (Thesis director) / Deviche, Pierre (Committee member) / Peartree, Natalie (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / School of Politics and Global Studies (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
There has been an alarming rise in the prevalence of obesity which has been attributed to the paralleled rise in consumption of high-fat foods. It’s commonly accepted that high-fat diets can lead to increased weight gain, however not all fats have the same physiological action. This study primarily focuses on the effect of canola oil, a monounsaturated fat, on energy homeostasis and body composition when it’s given as a supplement to a high-fat diet composed of saturated fatty acid. Rodent models were divided into three dietary groups: 1) low-fat diet (LFD), 2) high-fat diet (HFD) and 3) canola oils supplemented HFD (HF+CAN). After 4 weeks of dietary intervention, samples of epididymal fat, perinephric fat, and liver were analyzed across the three groups to see if the changes in energy homeostasis could be explained by the cellular behavior and composition of these tissues. Interestingly, the supplement of canola oil appeared to reverse the deleterious effects of a saturated fat diet, reverting energy intake, body weight gain and adipose tissue sizes to that (if not lower than that) of the LFD group. The only exception to this effect was the liver: the livers remained larger and fattier than those of the HFD. This occurrence is possibly due to a decrease in free fatty acid uptake in the adipose tissues—resulting in smaller adipose tissue sizes—and increased fatty acid uptake in the liver. The mechanism by which this occurs has yet to be elucidated and will be the primary focus of upcoming studies on the effect of monounsaturated fat on other diets.
ContributorsZuo, Connie Wanda (Author) / Washo-Krupps, Delon (Thesis director) / Deviche, Pierre (Committee member) / Herman, Richard (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Birds have unusually high plasma glucose concentrations compared to mammals of similar size despite their high metabolic rate. While birds use lipids as their main source of energy, it is still unclear how and why they maintain high plasma glucose concentrations. To investigate a potential underlying mechanism, this study looks at the role of lipolysis in glucose homeostasis. The purpose of this study is to examine the effects of decreased glycerol availability (through inhibition of lipolysis) on plasma glucose concentrations in mourning doves. The hypothesis is that decreased availability of glycerol will result in decreased production of glucose through gluconeogenesis leading to reduced plasma glucose concentrations. In the morning of each experiment, mourning doves were collected at the Arizona State University Tempe campus, and randomized into either a control group (0.9% saline) or experimental group (acipimox, 50mg/kg BM). Blood samples were collected prior to treatment, and at 1, 2, and 3 hours post-treatment. At 3 hours, doves were euthanized, and tissue samples were collected for analysis. Acipimox treatment resulted in significant increases in blood glucose concentrations at 1 and 2 hours post- treatment as well as renal triglyceride concentrations at 3 hours post-treatment. Change in plasma free glycerol between 0h and 3h followed an increasing trend for the acipimox treated animals, and a decreasing trend in the saline treated animals. These results do not support the hypothesis that inhibition of lipolysis should decrease blood glycerol and blood glucose levels. Rather, the effects of acipimox in glucose homeostasis appear to differ significantly between birds and mammals suggesting differing mechanisms for glucose homeostasis.
ContributorsKouteib, Soukaina (Author) / Sweazea, Karen (Thesis director) / Deviche, Pierre (Committee member) / Chandler, Douglas (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
In recent years the abuse of synthetic cathinones, "Bath Salts," has increased. The purpose of this study was to analyze two synthetic cathinones, methylone and α-pvp, for hedonic properties or the potential to be abused. This was tested using an intracranial self-stimulation paradigm, a robust measurement for reward. It was found methylone resulted in an abuse potential similar to MDMA, ecstasy, abuse. Moreover, the results for α-pvp showed a high liability for abuse.
ContributorsJohnson, Craig Trevor (Author) / Olive, Foster (Thesis director) / Presson, Clark (Committee member) / Montesano, Mark (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Department of Psychology (Contributor)
Created2013-12
Description
Testosterone (T) is a steroid hormone that affects behavior and reproductive traits (e.g. spermatogenesis and ornamentation) in vertebrates. In addition to long-term influences, T can rapidly increase in males following aggressive male-male encounters. Less is known how females directly influence male T and behavior, though research with humans suggests that sexually attractive females elicit a greater increase in male T and reproductive behavior than unattractive females. In birds, the influence of female attractiveness on male T and behavior is currently untested. We hypothesized that T and courtship behavior in male zebra finches would correlate with female attractiveness. We used red leg bands to make females "attractive" and green bands to make them "unattractive" (unbanded females were controls) as previous research suggests that zebra finches prefer red colors over green in mating contexts. We collected blood from males before and after "speed-dating" trials to measure changes in plasma T and analyzed male courtship behaviors from trial video recordings. The likelihood of plasma T increasing after a trial was significantly greater in males who were with red-banded females compared to control females, suggesting males may find them more attractive than green or control females. Additionally, independent of band color, males who exhibited greater T differences initiated courtship sooner and spent more time closest to females. However, courtship initiation and time spent near females were not correlated with band color. Overall, our results suggest that female attractiveness can influence male reproductive physiology, but the presence of a female may trigger male courtship behavior.
ContributorsBero-Buell, Brianna Danielle (Author) / McGraw, Kevin (Thesis director) / Deviche, Pierre (Committee member) / Ligon, Russell (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
This creative project explores the trend of designer/synthetic drug use in Arizona and nationwide. The project serves as "gap research" - bringing to light the problem of limited use statistics and constantly-changing drug chemical compounds. The project was thoroughly researched using media reports, psychology/drug addiction experts, community education organizers and available healthcare statistics. The results provided not definitive answer other than that more work needs to be done in the area of synthetic drug use. Parents and youth must educate themselves on the dangers of using these "legal" drugs.
ContributorsFischer, April Lee (Author) / Doig, Stephen (Thesis director) / Olive, Foster (Committee member) / Barrett, The Honors College (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor)
Created2014-05
Description
Menopause is reproductive senescence characterized by a loss of ovarian estrogen and progesterone. Women can experience cognitive decline and other negative symptoms with the loss of ovarian hormones (Sherwin, 2006). While hormone therapies (HT) can treat symptoms of menopause and may have neuroprotective properties, such as the potential to decrease the risk of Alzheimer's Disease (Behl & Manthey, 2000), there are many effects of current HTs that are not ideal. Indeed, optimizing conventional HTs has proven complex, indicating a need for alternative therapies. Phytoestrogens are estrogenic compounds found naturally in plants such as soybeans, that could provide new treatment options. Dietary phytoestrogens can benefit memory in the rodent model (Luine, 2006), although the mechanism underlying these effects is unclear. Basal forebrain cholinergic projections have been shown to mediate the cognitive benefits of estrogen (Gibbs, 2010); we hypothesize that phytoestrogens act similarly, via the cholinergic system, to impact memory. We administered varying doses of phytoestrogen-containing diets to ovariectomized female rats, and used the place recognition task to evaluate spatial memory. Brains were then analyzed for choline acetyltransferase (ChAT), the synthesizing enzyme for acetylcholine, in the vertical-diagonal bands (VDB) and the medial septum (MS) of the basal forebrain. Results showed that ChAT cell counts in the VDB were marginally higher with dietary phytoestrogen treatment. Further, VDB ChAT cell counts positively correlated with place recognition performance, indicating that animals with more VDB ChAT neurons exhibited better spatial memory performance. These results suggest that phytoestrogens might act similarly to natural, endogenously circulating estrogens, and identify phytoestrogens as a direction for investigation as a HT.
ContributorsMousa, Abeer Abdul (Author) / Bimonte-Nelson, Heather (Thesis director) / Olive, Foster (Committee member) / Deviche, Pierre (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / W. P. Carey School of Business (Contributor) / School of Life Sciences (Contributor) / School for the Science of Health Care Delivery (Contributor)
Created2014-05
Description
Rasopathies are a family of developmental syndromes that exhibit craniofacial abnormalities, cognitive disabilities, developmental delay and increased risk of cancer. However, little is known about the pathogenesis of developmental defects in the nervous system. Frequently, gain-of-function mutations in the Ras/Raf/MEK/ERK cascade (aka ERK/MAPK) are associated with the observed pathogenesis. My research focuses on defining the relationship between increased ERK/MAPK signaling and its effects on the nervous system, specifically in the context of motor learning. Motor function depends on several neuroanatomically distinct regions, especially the spinal cord, cerebellum, striatum, and cerebral cortex. We tested whether hyperactivation of ERK/MAPK specifically in the cortex was sufficient to drive changes in motor function. We used a series of genetically modified mouse models and cre-lox technology to hyperactivate ERK/MAPK in the cerebral cortex. Nex:Cre/NeuroD6:Cre was employed to express a constitutively active MEK mutation throughout all layers of the cerebral cortex from an early stage of development. RBP4:Cre, caMEK only exhibited hyper activation in cortical glutamatergic neurons responsible for cortical output (neurons in layer V of the cerebral cortex). First, the two mouse strains were tested in an open field paradigm to assess global locomotor abilities and overall fitness for fine motor tasks. Next, a skilled motor reaching task was used to evaluate motor learning capabilities. The results show that Nex:Cre/NeuroD6:Cre, caMEK mutants do not learn the motor reaching task, although they performed normally on the open field task. Preliminary results suggest RBP4:Cre, caMEK mutants exhibit normal locomotor capabilities and a partial lack of learning. The difference in motor learning capabilities might be explained by the extent of altered connectivity in different regions of the corticospinal tract. Once we have identified the neuropathological effects of various layers in the cortex we will be able to determine whether therapeutic interventions are sufficient to reverse these learning defects.
ContributorsRoose, Cassandra Ann (Author) / Newbern, Jason M. (Thesis director) / Olive, Foster (Committee member) / Bjorklund, Reed (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12