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Effects Of Aging And Strength Training On Shortening And Lengthening Muscle Actions In Women, Michelle Marie Porter
Effects Of Aging And Strength Training On Shortening And Lengthening Muscle Actions In Women, Michelle Marie Porter
Digitized Theses
There has been much research on strength changes with aging and the consequent effects of resistance training, however, relatively little is known about lengthening (eccentric; ECC) muscle actions. The purposes of these studies were to develop a method of testing and training plantar (PF) and dorsiflexion (DF) of the ankle in a standing position in order to investigate age-related and training effects on shortening (concentric; CONC) and ECC peak torque (PT) in women.;All subjects were healthy and physically active, and performed all testing and training on an isokinetic dynamometer. Strength testing was performed in both standing and supine positions at …
Properties And Regulation Of The Calcium Ion Pump In Heart And Skeletal Muscle Sarcoplasmic Reticulum, Cynthia Elaine Hawkins
Properties And Regulation Of The Calcium Ion Pump In Heart And Skeletal Muscle Sarcoplasmic Reticulum, Cynthia Elaine Hawkins
Digitized Theses
In heart and skeletal muscle, the sarcoplasmic reticulum (SR) plays a critical role in the contraction-relaxation cycle of the myocyte: a Ca{dollar}\sp{lcub}2+{rcub}{dollar} channel releases Ca{dollar}\sp{lcub}2+{rcub}{dollar} from SR into cytoplasm to trigger contraction, and a Ca{dollar}\sp{lcub}2+{rcub}{dollar} pump resequesters Ca{dollar}\sp{lcub}2+{rcub}{dollar} to cause relaxation. A major regulator of this cycle is {dollar}\rm Ca\sp{lcub}2+{rcub}{dollar}/calmodulin-dependent protein kinase (CaM kinase), which is known to phosphorylate and thereby activate the cardiac SR Ca{dollar}\sp{lcub}2+{rcub}{dollar} pump, Ca{dollar}\sp{lcub}2+{rcub}{dollar} channel and endogenous Ca{dollar}\sp{lcub}2+{rcub}{dollar}-pump inhibitor phospholamban. This thesis examines the Ca{dollar}\sp{lcub}2+{rcub}{dollar} pump and its regulation in different tissues (cardiac, slow-twitch and fast-twitch muscle SR: CMSR, SMSR and FMSR) and different stages in …
Limbic Mechanisms Controlling Arterial Pressure, Stefanie Roder
Limbic Mechanisms Controlling Arterial Pressure, Stefanie Roder
Digitized Theses
Three series of experiments were done to investigate the output pathways from the central nucleus of the amygdala (ACe) involved in the control of arterial pressure. The first series of experiments provided the first demonstration that the arterial pressure responses elicited during stimulation of ACe were mediated via a direct pathway to the bed nucleus of the stria terminalis (BST). Microinjection of retrograde tract tracers into depressor regions of BST resulted in labelled neurons within predominantly the lateral subdivision of ACe. In addition, iontophoresis of the anterograde tract tracer PHA-L into cardiovascular responsive regions of ACe resulted in fiber and …
Some Physiological Effects Of Stress In The American Cockroach Periplaneta Americana (L), Shigui Liu
Some Physiological Effects Of Stress In The American Cockroach Periplaneta Americana (L), Shigui Liu
Digitized Theses
The effects of different forms of stress on the American cockroach, Periplaneta americana (L.) have been systematically examined. This study demonstrated that at least two stress-related events occurred in the haemolymph of the American cockroach. First, the data clearly indicated that a large increase in hypertrehalosemic hormones occurred in the haemolymph of stressed cockroaches. Secondly, proteolytic activity in the haemolymph of stressed cockroaches was greatly increased. The increase of both hypertrehalosemic hormones and proteolytic activity in the haemolymph appeared to be a non-specific response to different forms of stress, including chemical poisoning with lindane, immobilization, forced movement, starvation, and elevated …
Role Of Nitric Oxide In Interleukin-2 Therapy-Induced Capillary Leak Syndrome, Amila Orucevic
Role Of Nitric Oxide In Interleukin-2 Therapy-Induced Capillary Leak Syndrome, Amila Orucevic
Digitized Theses
Systemic interleukin-2 (IL-2) therapy has been limited by a major side effect known as "capillary leak syndrome", characterized by retention of extravascular fluid, severe hypotension, and multiple organ system dysfunction. The present study tested the hypothesis that an overproduction of nitric oxide (NO) induced by IL-2 therapy was, at least in part, responsible for this syndrome. Studies were undertaken in healthy or C3-L5 mammary adenocarcinoma bearing C3H/HeJ mice to evaluate whether treatment with inhibitors of NO synthesis (N{dollar}\rm\sp{lcub}G{rcub}{dollar}-Methyl-L-Arginine, NMMA and N{dollar}\rm\sp{lcub}G{rcub}{dollar}-Nitro-L-Arginine methyl ester, L-NAME) can prevent IL-2 induced capillary leakage without compromising the therapeutic benefit of IL-2. Intraperitoneal IL-2 therapy …
Central Cardiorespiratory And Peripheral Metabolic Influences On Kinetics Of Oxygen Uptake In Older Humans, Philip David Chilibeck
Central Cardiorespiratory And Peripheral Metabolic Influences On Kinetics Of Oxygen Uptake In Older Humans, Philip David Chilibeck
Digitized Theses
The purpose of this thesis was to determine which factors influence oxygen uptake (VO{dollar}\sb2){dollar} kinetics during exercise in old individuals. These factors may include central {dollar}\rm O\sb2{dollar} delivery (i.e. cardiac output kinetics), the rate of O{dollar}\sb2{dollar} delivery at the exercising muscle, and the rate at which mitochondria can use O{dollar}\sb2.{dollar} Fitness level may also influence VO{dollar}\sb2{dollar} kinetics, by affecting the above factors. These factors were estimated by measuring heart rate (HR) kinetics, muscle capillarization, and citrate synthase (CS) activity, respectively, in groups of old ({dollar}\sim{dollar}65y) and young ({dollar}\sim{dollar}26y) individuals. Capillarization and CS activity of the lateral gastrocnemius were compared to …
Mechanisms Of Autonomic Control By The Insular Cortex In The Rat, Kenneth Scott Butcher
Mechanisms Of Autonomic Control By The Insular Cortex In The Rat, Kenneth Scott Butcher
Digitized Theses
The insular cortex (IC) has been proposed to act as visceral sensory and autonomic cortex. The mechanism of control by the IC, however, is not clear. The nature of insular cortical function in hypertension is also unknown.;Middle cerebral artery occlusion (MCAO) in Wistar rats has been shown to cause cortical infarction, including the IC, resulting in increases in sympathetic nerve discharge (SND). MCAO in the urethane anesthetized spontaneously hypertensive rat (SHR) resulted in decreases in arterial pressure (AP) and SND.;To determine if the autonomic effects of MCAO in the SHR and Wistar rat are due to insular damage, a lesion …
The Function Of Sarcoplasmic Reticulum In The Aged Rat Heart, Ming Tao Jiang
The Function Of Sarcoplasmic Reticulum In The Aged Rat Heart, Ming Tao Jiang
Digitized Theses
The purpose of this project was to study the effect of aging on the regulation of Ca{dollar}\sp{lcub}2+{rcub}{dollar} by cardiac sarcoplasmic reticulum (SR) and its potential contribution to the age-related alterations in myocardial contractile performance in Fischer 344 rats.;In cardiac membranes enriched in SR (MSR) and its light (LSR) and heavy (HSR) subfractions fractionated by a sucrose density gradient, the rate of ATP-supported and oxalate-facilitated Ca{dollar}\sp{lcub}2+{rcub}{dollar} uptake was significantly reduced (24-50%) in the aged (26-30 months old) compared with that of the adult rats (6-8 months old). With aging, the Ca{dollar}\sp{lcub}2+{rcub}{dollar}-stimulated phosphoenzyme of the Ca{dollar}\sp{lcub}2+{rcub}{dollar} pumps was reduced in MSR, LSR …
Neurotransmission Of Visceral Information In The Parabrachial Nucleus Of The Rat, Tarek Saleh
Neurotransmission Of Visceral Information In The Parabrachial Nucleus Of The Rat, Tarek Saleh
Digitized Theses
The parabrachial nucleus (PB) has been shown to be a major relay site for visceral afferents ascending through the ventrobasal thalamus and terminating in the insular cortex. The purpose of these investigations was to determine the neurotransmitter mechanisms in the PB involved in relaying visceral sensory information to the thalamus in the rat. Using electrophysiological techniques in the cloral hydrate anesthetised male Wistar rat, our results show that the visceral pathway from the PB to the thalamus appears to use two neuronal systems, one mediating the relay of specific visceral information via glutamatergic N-methyl D-aspartate (NMDA) receptors in the PB, …
Postsynaptic Cholinergic Control Of Cardiac Function In Aging, Na Su
Postsynaptic Cholinergic Control Of Cardiac Function In Aging, Na Su
Digitized Theses
The present study using isolated constant flow-perfused heart from adult (8 month-old) and aged (26 month-old) Fischer 344 rats for the first time demonstrated a striking enhancement of the negative chronotropic, inotropic and coronary vasoconstriction responses of the aging heart to postsynaptic cholinergic stimulation.;The approaches used and the results demonstrated were the following. (i) Acetylcholinesterase activity measured by the method of Ellman et al (1961) declined significantly in the atria and ventricles of the aged compared to adult rats. (ii) No age-related difference was seen in muscarinic receptor number in the atria and ventricles as assessed by {dollar}\lbrack\sp3\rm H\rbrack QNB{dollar} …
Role Of Protein Kinase C In Mediating The Effects Of Physiological And Pathophysiological Interventions In The Heart, Christopher Andrew Ward
Role Of Protein Kinase C In Mediating The Effects Of Physiological And Pathophysiological Interventions In The Heart, Christopher Andrew Ward
Digitized Theses
Protein kinase C has been implicated as a mediator of myocardial function following both physiological and pathophysiological stimuli. The purpose of the present study was to examine the functional effects of PKC in mediating phorbol esters as well as receptor-induced effects in myocardial tissues. Additionally, the possible role of PKC in mediating cardiac pathophysiology was assessed under conditions which mimicked aspects of myocardial ischemia/reperfusion. The effects of phorbol esters on cardiac function were assessed in isolated perfused guinea pig hearts. The effects of phorbol esters, acidosis/realkalinization and hydrogen peroxide were assessed in isolated guinea pig ventricular myocytes to determine PKC-dependent …
The Interaction Of Thyroid Stimulating Hormone (Tsh), Insulin-Like Growth Factors (Igfs), And Insulin-Like Growth Factor Binding Proteins (Igfpbs) In The Regulation Of The Synthesis And Secretion Of Thyroid Hormones By Cultured Sheep Thyroid Cells, Jia Fang Wang
Digitized Theses
Thyroid growth and function are regulated by TSH in synergy with other hormones, growth factors, and neurotransmitters. Insulin-like growth factors (IGFs), which have insulin-like effects on metabolism and regulate cell growth and function, are synthesized and secreted by thyroid cells. IGFs are associated with their specific binding proteins (IGFBPs), which not only carry and store IGFs in body fluids but also modulate the biological function of IGFs. Previous studies found that both IGFs and IGFBPs participated in the regulation of the growth of thyroid cells.;This study has further examined the biological function of IGFs and IGFBPs in the regulation of …
The Putative Role Of Fatty Acids In The Activation Of Trehalose Synthesis In The Fat Body Of The Cockroach Periplaneta Americana L, Irshad Ali
Digitized Theses
Hypertrehalosemic hormones produced by the corpus cardiacum increase the concentration of several fatty acids in cockroach fat body trophocytes. The phospholipase A{dollar}\sb2{dollar} (PLA{dollar}\sb2){dollar} activator melittin has a similar effect. The fatty acids include palmitic, stearic, oleic and linoleic acid. The hormone mediated release of these fatty acids is blocked by the PLA{dollar}\sb2{dollar} inhibitors mepacrine and {dollar}\rho{dollar}-bromophenacyl bromide. These observations suggest that hormonal release of fatty acids, may be due to the activation of PLA{dollar}\sb2.{dollar};The increase in non-esterified fatty acids appears to be linked to the increase in trehalose efflux since sugar efflux is stimulated by stearic, oleic, linoleic and arachidonic …
Feedback Control Mechanisms Regulating Breathing In Humans, Croix Claudette St
Feedback Control Mechanisms Regulating Breathing In Humans, Croix Claudette St
Digitized Theses
The respiratory system regulates alveolar ventilation (V{dollar}\sb{lcub}\rm A{rcub}{dollar}) almost exactly to the demands of the body so that the PCO{dollar}\sb2{dollar} and PO{dollar}\sb2{dollar} of the arterial blood are hardly altered, even during strenuous exercise or other types of respiratory stress. The feedback control of ventilation was studied in human subjects using the technique of dynamic end-tidal forcings to produce perturbations in end-tidal PCO{dollar}\sb2{dollar} (P{dollar}\sb{lcub}\rm ET{rcub}{dollar}CO{dollar}\sb2{dollar}) and end-tidal PO{dollar}\sb2{dollar} (P{dollar}\sb{lcub}\rm ET{rcub}{dollar}O{dollar}\sb2{dollar}) to stimulate the respiratory chemoreceptors.;The purpose of the first study was to investigate the interaction between ventilatory drives from the central (cR{dollar}\sb{lcub}\rm c{rcub}{dollar}) and peripheral (pR{dollar}\sb{lcub}\rm c{rcub}{dollar}) chemoreceptors using their different …
Epidermal Growth Factor Regulation Of Porcine Oocyte Maturation And Cumulus Cell Expansion In Vitro, Balwant Singh
Epidermal Growth Factor Regulation Of Porcine Oocyte Maturation And Cumulus Cell Expansion In Vitro, Balwant Singh
Digitized Theses
The overall objective of this study was to investigate the role in vitro of epidermal growth factor (EGF) in the regulation of both nuclear and cytoplasmic maturation of the porcine oocyte, and in the expansion of cumulus cells.;Studies aimed at the induction of oocyte maturation and cumulus expansion revealed that EGF is a potent stimulant of the resumption of meiosis in the oocyte and that the addition of FSH, but not LH, to EGF further enhances its effect on germinal vesicle breakdown (GVBD). Both estradiol-17{dollar}\beta{dollar} (E{dollar}\sb2{dollar}) and androstenedione (A{dollar}\sb4{dollar}) inhibited FSH-stimulated GVBD, but had no effect on EGF-stimulated GVBD, suggesting …
Pre-Cataractous Loss Of Cellular Antioxidants And Atp In The Diabetic Rat Lens, Kenneth Patrick Mitton
Pre-Cataractous Loss Of Cellular Antioxidants And Atp In The Diabetic Rat Lens, Kenneth Patrick Mitton
Digitized Theses
The in vivo streptozotocin-induced diabetic rat model of cataract is one of the oldest animal models of cataractogenesis available, however investigation of diabetic lenses before the formation of liquid-filled vacuoles, is lacking. Using analysis specific for glutathione, it was found that pre-vacuolar diabetic rat lenses lost glutathione (GSH) (85%) compared to normal lenses. Glutathione disulphide (GSSG) did not appear in diabetic lenses. Lens ascorbate concentration was also decreased by 48% in pre-vacuolar diabetic lenses compared to normal lenses.;ATP loss, previously demonstrated only in post-vacuolar diabetic lenses, was found in pre-vacuolar diabetic lenses compared to normal lenses. It is possible that …
Central Neuronal Circuits Involved In The Reflex Control Of The Cardiovascular System, Douglas James Mckitrick
Central Neuronal Circuits Involved In The Reflex Control Of The Cardiovascular System, Douglas James Mckitrick
Digitized Theses
To reveal central nervous system (CNS) structures involved in the reflex control of the cardiovascular system, the distribution of Fos protein-like immunoreactivity (FLI) was examined in the brains of urethane anesthetized rats following stimulation of the aortic depressor (ADN) and femoral (FN) nerves. First, the ADN was cut bilaterally in 13 rats, the central ends were placed on stimulating electrodes and stimulated for 1 h. CNS sections were incubated in anti-Fos antibody and prepared immunohistochemically for visualization of FLI. Label was found on the side ipsilateral to the side of stimulation in discrete nuclei in the hindbrain, midbrain and forebrain …
Corticosteroid-Binding Globulin In Fetal And Adult Sheep, Edward Terry Berdusco
Corticosteroid-Binding Globulin In Fetal And Adult Sheep, Edward Terry Berdusco
Digitized Theses
In the ovine fetus, plasma cortisol is bound by its high affinity binding protein corticosteroid-binding globulin (CBG). Plasma CBG concentrations increase during late gestation, but the stimulus for this increase and its consequences in the fetal sheep are not known. These studies were undertaken to examine the stimulus for an increase in fetal plasma CBG, the mechanism of this increase, and the physiological significance of the increase.;Chronically catheterized fetal and adult sheep were used to examine the changes in late gestation of plasma CBG concentrations, plasma CBG glycosylation, total and free cortisol, and effects of glucocorticoids on plasma CBG. An …
Functional Regulation Of The Pituitary-Adrenal Axis In The Ovine Fetus, Feng Lu
Functional Regulation Of The Pituitary-Adrenal Axis In The Ovine Fetus, Feng Lu
Digitized Theses
The purpose of the present study was to elucidate the mechanisms regulating function of the ovine fetal pituitary-adrenal axis by hypothalamic, pituitary and adrenal factors, and by locally produced growth factors. Specifically, the effects of corticotropin releasing hormone (CRH), arginine vasopressin (AVP) and cortisol on CRH binding, levels of proopiomelanocortin (POMC) mRNA and adrenocorticotropin (ACTH) output from the fetal ovine anterior pituitary were evaluated in vitro. Further, expression of the insulin-like growth factor (IGF) genes and possible roles of IGFs in the ovine fetal pituitary-adrenal axis were examined.;Our studies provide the following results: (1) The number of CRH binding sites …
Uterine Vascular Permeability, Extracellular Fluid Volume And Blood Flow Following Deciduogenic Stimulation Of Rats, Gavin Scot Hamilton
Uterine Vascular Permeability, Extracellular Fluid Volume And Blood Flow Following Deciduogenic Stimulation Of Rats, Gavin Scot Hamilton
Digitized Theses
The present study examined the possible importance of uterine vascular permeability (VP), extracellular fluid volume (ECFV) and blood flow (BF) in the enhanced accumulation of serum proteins in uterine tissue destined to undergo decidualization. This process is identifiable by endometrial blueing after intravenous (i.v.) injection of Evans blue dye. It was hypothesized that VP, ECFV and BF must increase to promote the enhanced intrauterine accumulation of serum proteins and that these uterine vascular and perivascular changes require optimal endometrial sensitization and prostaglandins (PGs).;ECFV was estimated by the uterine volume of distribution of i.v. injected {dollar}\sp{lcub}51{rcub}{dollar}Cr-EDTA, VP by the rate of …
Binocular Interactions In Individuals With Anomalous Early Visual History, Marla Ellen Wolf
Binocular Interactions In Individuals With Anomalous Early Visual History, Marla Ellen Wolf
Digitized Theses
The present set of experiments used adaptation procedures to explore binocularity in individuals with abnormal binocular vision. The first series of experiments examined interocular transfer because this measure has been used previously to test for the presence of binocular neurons (Movshon, Chambers and Blakemore, 1972). Experiment I examined the test-retest reliability of this measure. Interocular transfer was found to be reliable. The results of Experiments II-IV clearly show that individuals with anomalous early visual history (A.E.H.) are capable of interocular transfer of a magnitude associated with normals.;Experiments III and IV also addressed the organization of binocular channels in individuals with …
Hsp 72 In Rat Skeletal Muscle: Fibre Type Differences And Effect Of Exercise, Marius Locke
Hsp 72 In Rat Skeletal Muscle: Fibre Type Differences And Effect Of Exercise, Marius Locke
Digitized Theses
Western blot analyses of SDS-PAGE separated proteins from various hindlimb muscles from non-exercised control animals probed with an HSP 72 monoclonal antibody, demonstrated the constitutive expression of HSP 72 in rat muscles comprised primarily of Type I muscle fibres (soleus), but not in muscles comprised primarily of Type IIB/X fibres (white gastrocnemius-WG). In muscles of mixed fibre type, (plantaris and red gastrocnemius-RG) HSP 72 content was proportional to the percentage of Type I fibres.;Immunolocalization of HSP 72 in cross-sections from the soleus muscle demonstrated that both Type I and Type IIA fibres expressed HSP 72, but Type I fibres expressed …
Cyclic Adenosine 3',5'-Monophosphate And Prostaglandin E(2) During Decidualization In The Rat, Gayle M. Yee
Cyclic Adenosine 3',5'-Monophosphate And Prostaglandin E(2) During Decidualization In The Rat, Gayle M. Yee
Digitized Theses
Prostaglandin E{dollar}\sb2{dollar} (PGE{dollar}\sb2{dollar}) is an important mediator of implantation and decidualization during pregnancy. However, its mechanism of action in the uterus is unclear. Endometrial alkaline phosphatase (ALP) activity increases during decidualization in many species and provides a marker for assessment of cellular aspects of decidualization. The objective of this study was to examine the relationship between PGE{dollar}\sb2{dollar} and cyclic adenosine 3{dollar}\sp\prime{dollar},5{dollar}\sp\prime{dollar}-monophosphate (cAMP) during decidualization in the rat. In ovariectomized rats treated with estrogen and progesterone to sensitize the uteri for decidualization, intrauterine infusion of indomethacin, an inhibitor of endogenous PG synthesis, inhibited the increase in endometrial ALP activity, which occurred …
Ventilatory Response To Carbon Dioxide Stimuli In Aged Humans, Marc Jean Poulin
Ventilatory Response To Carbon Dioxide Stimuli In Aged Humans, Marc Jean Poulin
Digitized Theses
This thesis examined age-related changes in the ventilatory response to exercise and in the ventilatory response to inhaled carbon dioxide (CO{dollar}\sb2{dollar}) at rest. Specifically, the purposes were to: (1) examine the ventilatory response to CO{dollar}\sb2{dollar} production (VCO{dollar}\sb2{dollar}) during graded exercise below the ventilation threshold (T{dollar}\sb{lcub}\rm \.VE{rcub}{dollar}) in men and women aged 55 to 86 yrs, (2) determine the ventilatory response to CO{dollar}\sb2{dollar} at rest and evaluate the CO{dollar}\sb2{dollar} sensitivity of the central and peripheral chemoreceptors in young (YS, n = 7, 28.3 yrs) and old (OS, n = 11, 76.1 yrs) humans, and (3) determine the temporal parameters of the …
Age-Related Changes In The Numbers And Physiological Properties Of Human Motor Units, Timothy John Doherty
Age-Related Changes In The Numbers And Physiological Properties Of Human Motor Units, Timothy John Doherty
Digitized Theses
Age-related changes in the numbers and physiological properties of human motor units (MUs) were examined in four studies.;In the first study, spike-triggered averaging was used to estimate the numbers of MUs in the biceps brachii and brachialis muscles. The maximum isometric twitch contraction (MTC) and maximum voluntary contraction (MVC) of the elbow flexors were also measured. In older subjects, the estimated numbers of MUs were significantly reduced (47%) whereas, average surface-detected motor unit action potential (S-MUAP) sizes were significantly larger (23%). Significant but less marked age-associated reductions were found for the MTC (33%) and MVC (33%).;In the second study Multiple …
Control Of Tonic Sympathetic Nerve Activity By The Brainstem In Rats, Kristen Hayes
Control Of Tonic Sympathetic Nerve Activity By The Brainstem In Rats, Kristen Hayes
Digitized Theses
Control of tonic firing of sympathetic nerves by the rostral ventrolateral medulla (RVLM) and the pontine reticular formation (PRF) was investigated. Electrical activity of renal, splenic, mesenteric and preganglionic greater splanchnic nerves and T{dollar}\sb{lcub}13{rcub}{dollar} white rami was recorded in artificially respired, urethane-anaesthetized rats. Glycine (1.0M;180nl) was microinjected into the RVLM to inhibit neuronal discharge and effects on these nerves were compared. To study descending inhibitory influences on these nerves, effects of RVLM blockade were compared to effects of cervical spinal cord transection. RVLM blockade caused greater decreases in discharge of renal ({dollar}-44\ \pm\ 3\%{dollar}) than splenic ({dollar}-31\ \pm\ 2\%{dollar}) nerves, …
Regulation Of Choline Acetyltransferase In Rat Hippocampal Synaptosomes, Bonnie Marie Schmidt
Regulation Of Choline Acetyltransferase In Rat Hippocampal Synaptosomes, Bonnie Marie Schmidt
Digitized Theses
Choline acetyltransferase (ChAT; EC 2.3.1.6) catalyses the biosynthesis of acetylcholine (ACh) from choline and acetylCoenzyme A in cholinergic neurons. Within nerve terminals, this enzyme exists in both cytosolic and membrane-bound forms, although the role of the latter fraction is not clear. ChAT is clearly subject to long-term regulation (over periods of hours to days), likely through alterations in protein synthesis, however very little is known about short-term regulation (seconds to minutes). Therefore, the goals of this study were to determine the mechanisms of short-term regulation of ChAT activity and to elucidate the physiological role of membrane-bound ChAT in ACh biosynthesis.;Using …
Blood-Nervous Tissue Barriers In The Peripheral Nervous System, Deborah Tristram Allen
Blood-Nervous Tissue Barriers In The Peripheral Nervous System, Deborah Tristram Allen
Digitized Theses
After years of investigation into blood-nervous tissue barriers controversies remain regarding the permeability of blood vessels to macromolecules in the enteric nervous system, the endoneurium of peripheral nerve, and the spaces between satellite cells and neurons in sensory and sympathetic ganglia.;The permeability of the above areas of the peripheral nervous system was investigated in rats using the following intravenously administered tracers: rhodamine-labelled bovine albumin; horseradish peroxidase; acriflavine and ethidium. The last two, which are fluorescent cationic dyes were shown to bind to serum proteins. In addition immunohistochemical staining for endogenous albumin was performed. One long-term study was done in which …
Myocardial Electrophysiological Alterations In Pacing-Induced Heart Failure And Defibrillation Shock Delivery, Huagui Li
Digitized Theses
Heart failure patients frequently have ventricular arrhythmias and high incidence of sudden death. Current antiarrhythmic drug therapies have failed to improve the survival of these patients as the arrhythmogenesis is poorly understood. The only effective therapy for lethal arrhythmia, ventricular fibrillation, is electrical shock (defibrillation). Studies on arrhythmogenesis and potential antiarrhythmic therapies in heart failure are needed.;This thesis investigated: (1) cardiac electrophysiological changes and arrhythmogenesis in a heart failure model; (2) cellular electrophysiological effects of defibrillation shocks.;Heart failure was produced by rapid ventricular pacing (240 beats/min, 4-5 weeks) in 35 dogs. Twenty-one operated, non-paced dogs served as control. Increased impulse …
Age-Associated Changes In The Kinetics Of Ventilation And Pulmonary Gas Exchange, Mark Anthony Babcock
Age-Associated Changes In The Kinetics Of Ventilation And Pulmonary Gas Exchange, Mark Anthony Babcock
Digitized Theses
The purpose of these studies was to examine ageing effects on the dynamics of pulmonary gas exchange and ventilation during the transition from light to moderate work. In the first study maximal oxygen uptake (VO{dollar}\sb2{dollar}max), ventilation threshold (VeT), the time constant for VO{dollar}\sb2{dollar} ({dollar}\tau\sp\prime{dollar}VO{dollar}\sb2{dollar}), and efficiency were determined from a ramp forcing test in eighty-three males aged 30 to 84y. The results showed a decline in VO{dollar}\sb2{dollar}max with age of {dollar}-{dollar}0.037 1{dollar}\cdot{dollar}min{dollar}\sp{lcub}-1{rcub}{dollar} per year. The VeT also declined with age but at one-third the rate of loss of the VO{dollar}\sb2{dollar}max. The {dollar}\tau\sp\prime{dollar}VO{dollar}\sb2{dollar} increased with age; the older group (60+y) had …