Thesis (M.S.)--Brandeis University, 2009. / Title from PDF title page (viewed on May 29, 2009). Includes bibliographical references.

Thesis (M.S.)--University of British Columbia, 2005. / Includes bibliographical references (leaves 89-97). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--University of British Columbia, 2005. / Includes bibliographical references (leaves 89-97).

Thesis (Ph. D.)--Georgia State University, 2005. / Timothy Bartness, committee chair; Elliott Albers, Ruth Harris , Sarah Pallas, committee members. Electronic text (181 p. : ill.)) : digital, PDF file. Description based on contents viewed July 17, 2007. Includes bibliographical references (p. 148-181).

This project involved the study of mechanisms which modulate autonomic transmission within the sympathetic nervous system using the mouse vas deferens as a model tissue. Data was collected using contraction studies, electrophysiological techniques with sharp microelectrodes, and fluorescent calcium imaging of both smooth muscle cells and nerve terminal varicosities. An additional series of experiments was conducted using the PC12 cell line, derived from a phaeochromocytoma of the rat adrenal medulla, for flow cytometry experiments using fluorescence-activated cell sorting. During the course of this project a novel technique for studying the activity of the norepinephrine transporter within a whole organ preparation was developed using the neurotransmitter uptake assay. The uptake of this assay within the nerve terminals of the vas deferens was abolished by desipramine whilst its rate of washout was increased by amphetamine. However, some non-neuronal, peri-nuclear staining which could not be prevented by a range of pharmacological means was also observed. This new technique was then used in other work exploring putative NET regulation by cannabinoids. The modulatory effects of two pharmacological groups were assessed: testosterone and cannabinoids. Testosterone was found to have a rapid, non-genomic effect inhibiting neurotransmission within the vas deferens. This was a postjunctional effect which appeared to involve modulation of the opening of L-type calcium channels on the smooth muscle cells. For the studies of cannabinoids, two broad areas of research were conducted. First the effects of Δ⁹-tetrahydrocannabinol were investigated with regard to the pre-junctional release of neurotransmitters and the effect of THC on calcium dynamics within individual nerve terminal varicosities. Secondly, a surprising novel effect upon the norepinephrine transporter was identified and examined. This inhibitory effect was revealed initially by contraction experiments demonstrating a decrease in the rate of uptake of noradrenaline from the junction. This work demonstrates that there are still novel modes of regulation of sympathetic transmission to be uncovered. The ongoing challenge is to establish their role within physiology and pathophysiology.

abstract: The objective of this study was to examine the potential effects of long term hormone replacement therapy on cardiovascular autonomic nervous system responses to laboratory social stressors. The participants were 38 postmenopausal women, 18 using estrogen and progesterone hormone replacement therapy for at least 2 years and 20 control participants without hormone replacement therapy. All women completed orthostasis (standing and sitting), then speech and math tasks (speech and math were counterbalanced). Cardiovascular measures of sympathetic nervous system (pre-ejection period, PEP) and parasympathetic nervous system (respiratory sinus arrhythmia, RSA) along with heart rate were collected throughout all periods (baseline, orthostasis, and stressors). For orthostasis, results of mixed analyses of variance (ANOVAs) showed expected period effects for heart rate, RSA and PEP, but no group or group by period interaction was significant. For the psychological stressors, period main effects were significant for all three variables, suggesting that the tasks were effective at inducing stress. Also, there was a significant interaction between group and period for RSA, demonstrated by greater decrease during the psychological stressor period in the group using HRT. The interactions between group and period for heart rate and PEP were non-significant. These findings support the notion that HRT may slow age-related decreases in parasympathetic responsiveness. Furthermore, changes in vagal reactivity in relation to use of HRT appear to occur within mechanisms involving response and coping with psychological stressors, rather than mechanisms that accommodate basic physiological task such as orthostasis. / Dissertation/Thesis / M.S. Psychology 2013

Methyldopa (L-alpha-Methyl-3,4-dihydroxyphenylalanine) is a catecholamine used as an antihypertensive agent.1 Alpha-Methyldopa is not used as frequently anymore due to side effects, but it is still used especially in developing countries due to its low cost. Indications are mostly for the management of pregnancyinduced hypertension (PIH), as it is relatively safe in pregnancy compared to other antihypertensive drugs. This project is intended to increase the already-existing knowledge base of the mechanism of pharmacological action and to stimulate further investigation through research. The sympathetic nervous system is a division of the autonomic nervous system and it is responsible for the “flight-or-fight” response. It is involuntary and constantly active to maintain homeostasis in the human body. Sympathetic responses include an increase in heart rate, blood pressure and cardiac output, dilation of pupils and bronchioles, constriction of blood vessels, contraction of sphincters and inhibition of gut motility and secretions. The purpose of this study is to evaluate the activity of the sympathetic nervous system of volunteers by three different techniques (QT interval and Heart rate variability and Skin conductance) after a week of a bi-daily dosage of alphamethyldopa. All volunteers received either 250mg alpha-methyldopa orally or a placebo tablet in a randomized, double blind, placebo controlled study design. The correlation between the following techniques was also evaluated: Skin conductance as measured by the ProComp Infiniti Biofeedback apparatus, QT interval on ECG and HRV measured with Viport apparatus. A salivary sample was collected to evaluate the effect of alpha-methyldopa on salivary cortisol using an ELISA kit for analysis. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Pharmacology / unrestricted

Diabetes mellitus (DM) and hyperglycemia contribute to sympathetic nervous system (SNS) activation and cardiovascular dysfunction. SNS activation and increased norepinephrine levels downregulate cardiac β-adrenergic receptors (β-AR). The ADMIRE-HF trial identified reduced cardiac SNS innervation as an independent prognostic marker in heart failure. The β-AR antagonist [3H]-CGP12177 was used to quantify cardiac β-AR in ex vivo biodistribution studies in streptozotocin (STZ)-treated rats after 8 weeks of sustained hyperglycemia, and in the Zucker Diabetic Fatty (ZDF) rat model of type-2 diabetes at the onset of hyperglycemia (10 weeks of age) and after a sustained period of hyperglycemia (16 weeks of age). In some STZ rats, insulin was provided at the onset of hyperglycemia, or after a sustained period of hyperglycemia. Insulin treatment at both time points prevented reduced [3H]-CGP12177 binding (33-38% compared to controls) observed in STZ hyperglycemics. ZDF β-ARs were intact at 10 weeks but became reduced (16-25% relative to the Zucker leans) following 6 weeks of hyperglycemia. This work supports that cardiac β-AR are reduced in models of DM and that restoring insulin signalling to maintain glycemic control can normalize β-AR density whether provided early or after a period of sustained hyperglycemia.

The nervous system and immune system contact one another through two-way communication in order to establish and preserve homeostasis. The sympathetic neurotransmitter norepinephrine has an impact on how the immune system responds by affecting regional blood flow and activation of adrenergic receptors on leukocytes. Former studies showed that immune cells are capable of releasing nerve growth factor allowing for the establishment and continuation of sympathetic nerves in targeted tissues. From this gathered information, it was hypothesized that sympathetic nerves would prove to be less frequent in spleens from the immunodeficient R2G2 mouse strain (Envigo) when compared to 129P3/J (129) and C57BL/6 (C57) strains. R2G2 mice are an immunodeficient strain that lacks functional T, B, and natural killer cells. Ten to eleven week aged-matched male mice were measured by body weight, spleen weight, and temperature. Spleens were cut and fixed for histological investigation. Sympathetic nerves were labeled by immunostaining tyrosine hydroxylase (TH). Hematoxylin & eosin (H&E) was used to stain spleen sections in order to evaluate cytoarchitecture. Von Willebrand factor (VWF) was used to immunostain for megakaryocytes. R2G2 mice showed slightly higher temperatures and body weights but yielded a significantly smaller spleen weight (R2G2, 38.20 ± 1.48; 129, 65.08 ± 11.71; C57, 81.33 ± 8.38; P< 0.0001, ANOVA). TH stain revealed sympathetic innervation in all strains but location and morphology differed in R2G2 mice compared to controls. Control spleens had nerves which entered white pulp regions of the spleen and were closely related to leukocytes. Fiber profiles in the controls were filamentous with small acute bends. R2G2 differed by having (TH+) nerve fibers more associated with arteries and less localized in the surrounding parenchyma. The fibers were abnormally swollen and held a more granular shape instead of a filamentous shape. The H&E stain showed clear red and white pulp zones in the control spleens with 129 showing more distinct germinal centers than C57. R2G2 H&E sections showed cytoarchitecture with indistinct pulp areas. VWF staining revealed R2G2 mice had an abundant amount of megakaryocytes versus control mice megakaryocyte counts (R2G2, 11.28 ± 3.87 per 20X field; 129, 1.73 ± 0.70; C57, 1.42 ± 0.13; P< 0.0001, ANOVA) and extramedullary hematopoiesis was highly prominent. This evidence supports that leukocytes secrete neurotrophic factors or are vital to establishing normal growth of TH+ nerves toward the white pulp. Leukocytes may not be required for sympathetic innervation of blood vessels in the spleen, however, lack of leukocytes shows TH+ nerve fibers with abnormal morphology in severely immune threatened mice.

Cardiovascular disease (CVD) is the leading cause of death worldwide. Pre-menopausal women have a lower incidence and severity of CVD compared to age-matched men. However, at the onset of menopause, CVD increases. A central feature in patients with CVD is excessive chronic sympathetic stimulation (CSS) of β-adrenergic receptors (β-AR’s). Clinical and animal studies show estrogen deficiency and age exacerbate cardiac β-AR signaling and contractile function. This led to the hypothesis that prolonged estrogen deficiency followed by CSS worsens left ventricular cardiac function and hypertrophy in the aged female heart. Female mice underwent bilateral ovariectomy or SHAM surgery at 2.5 months of age. At 12 months post-ovariectomy, mice were infused with Isoproterenol (400μg/kg/h) via mini-osmotic pumps for three days to induce CSS. This observation demonstrates prolonged estrogen deficiency worsens cardiac function and structure in aged female hearts. Thereby emphasizing the importance of clinical intervention and prevention for CVD in menopausal women.