SPECIFIC MODIFICATION OF SKELETAL MUSCLE RYANODINE RECEPTOR ACTIVITY
Funder
National Health and Medical Research Council
Funding Amount
$411,000.00
Summary
The project will have implications for muscle fatigue, which is a public health issue in an aging population, and for neuromuscular diseases and muscle weakness. The ryanodine receptor (RyR) calcium release channel regulates changes in calcium concentrations inside the muscle cell that are essential for respiration and movement. Defects in expression of RyRs results in death in utero or at birth. The RyR is also important in many other tissues, where it acts either alone or in combination with a ....The project will have implications for muscle fatigue, which is a public health issue in an aging population, and for neuromuscular diseases and muscle weakness. The ryanodine receptor (RyR) calcium release channel regulates changes in calcium concentrations inside the muscle cell that are essential for respiration and movement. Defects in expression of RyRs results in death in utero or at birth. The RyR is also important in many other tissues, where it acts either alone or in combination with a second type of calcium channel, to regulate the changes in the concentrations of calcium ions within the cell, which are essential for a variety of processes including cardiac contraction, vascular constriction, neuronal activity and immune responses. Despite its importance, little is known about the regulation of the RyR channel opening during contraction in skeletal muscle or the mechanisms of ion movement through its pore. It is often difficult to define the specific role of RyRs in intact tissues because of the lack of specific probes for the channel. The RyR is an obvious target for therapeutic drugs to modify muscle contraction, but has not been used as such because of the lack of specific and reversible drugs. Muscle performance is reduced, and fatigue is rapid, in neuromuscular disease. Performance can be improved by variety of drugs like anabolic steroids which unfortunately have additional adverse actions. The aims of the project are (a) to discover more about the regulation of, and ion conduction pathway through, the skeletal muscle RyR channel, (b) to identify compounds that can be used as specific probes for RyR activity and (c) to identify compounds that might in the future provide the basis for development of the RyR as a therapeutic target.Read moreRead less
Opioid Actions On Identified Sensory Neurons In Vitro
Funder
National Health and Medical Research Council
Funding Amount
$371,850.00
Summary
Opioids (in particular morphine) are the gold standard drugs for the relief of most types of moderate to severe pain. Despite the effectiveness of opioids and other analgesics, many people still suffer unrelieved pain. There are 2 main reasons for this. Firstly, there are some types of pain that are refractory to currently used analgesics from the outset, and secondly, chronic conditions may require escalating doses of analgesics for adequate pain relief, and these does may increase until side e ....Opioids (in particular morphine) are the gold standard drugs for the relief of most types of moderate to severe pain. Despite the effectiveness of opioids and other analgesics, many people still suffer unrelieved pain. There are 2 main reasons for this. Firstly, there are some types of pain that are refractory to currently used analgesics from the outset, and secondly, chronic conditions may require escalating doses of analgesics for adequate pain relief, and these does may increase until side effects become intolerable. My studies will provide insight into the reasons that underlie the differential effectiveness of opioids in acute pain conditions, as well as the reasons why opioids lose their effectiveness over time. These studies will also identify molecular targets that may be important for developing analgesics for specific pain conditions. Because the head is the source of many familiar painful conditions, including tooth pain, migraine and temporomandibular disorders, I will be using neurons from the trigeminal ganglion, the part of the nervous system which supplies the sensory innervation to the structures involved in these pain states. By using mice as experimental animals, I will be able to investigate the contribution of neurons that innervate specific parts of the head to these pain states, and study how chronic morphine treatment affects the behavior of these cells. I hope that these studies will provide a basis for designing strategies that improve the effectiveness of existing analgesics, and perhaps lead to the identification of new, better pain relievers.Read moreRead less
Impact Of Airway Wall Fibrosis On The Efficacy Of Anti-asthma Drugs
Funder
National Health and Medical Research Council
Funding Amount
$432,750.00
Summary
Most episodes of asthma are controlled or prevented by current medications. In a small, but significant proportion of asthmatics (5-10%) symptoms persist despite the use of the best combinations of anti-asthma drugs. One of the reasons that acute episodes of asthma occur is that the airway tubes slowly change in structure. These changes involve an increase in the amount of collagen (part of the cement between cells) making the airway stiffer. In this project, we are exploring the impact of the s ....Most episodes of asthma are controlled or prevented by current medications. In a small, but significant proportion of asthmatics (5-10%) symptoms persist despite the use of the best combinations of anti-asthma drugs. One of the reasons that acute episodes of asthma occur is that the airway tubes slowly change in structure. These changes involve an increase in the amount of collagen (part of the cement between cells) making the airway stiffer. In this project, we are exploring the impact of the stiffening of the airway on the way that different cells within the airway wall respond to drugs used to treat asthma. Our initial findings suggest that when the airway wall becomes stiffer with more collagen, there is a diminished benefit from the anti-asthma drugs. This new study is designed to identify the molecular mechanisms for the poor response to the anti-asthma drugs. With this knowledge it will be easier to design and test new drugs that are more effective in severe asthma.Read moreRead less
Pharmacological Regulation Of Airway Smooth Muscle Phenotype
Funder
National Health and Medical Research Council
Funding Amount
$276,742.00
Summary
In Australia there is a high incidence of asthma which impairs quality of life and can sometimes cause death if sufficiently severe. The main cause of asthma is the shortening of muscle surrounding the airway passages that cause the narrowing of these tube-like passages. When airway passages narrow a feeling of chest tightness is perceived by the asthmatic patient. When the narrowing is severe the amount of oxygen being delivered to the blood can be reduced to dangerous levels. When there is mus ....In Australia there is a high incidence of asthma which impairs quality of life and can sometimes cause death if sufficiently severe. The main cause of asthma is the shortening of muscle surrounding the airway passages that cause the narrowing of these tube-like passages. When airway passages narrow a feeling of chest tightness is perceived by the asthmatic patient. When the narrowing is severe the amount of oxygen being delivered to the blood can be reduced to dangerous levels. When there is muscle growth in the airways even small amounts of shortening of the muscle can cause severe narrowing of the airway passages. This research will investigate how muscle grows in asthmatic airways and look for new ways to use drugs to treat this muscle growth. We hope to improve drug treatment of asthma by limiting the amount of airway narrowing caused by muscle contraction.Read moreRead less
Airway Smooth Muscle Contribution To Remodelling In Asthma.
Funder
National Health and Medical Research Council
Funding Amount
$211,320.00
Summary
Asthma is an airway disease that affects more than 10% of adults and 25% of children in Australia and in 1998 caused 675 deaths. The cost to the community is in excess of $720 million a year. The abnormality in asthma is not fully understood, however inflammation, changes to the structure of the airways and excessive airway narrowing are key factors. Inflammation and the allergic reactions which accompany asthma cause fluid to leak from tiny blood vessels in the lung. This fluid and the inflamma ....Asthma is an airway disease that affects more than 10% of adults and 25% of children in Australia and in 1998 caused 675 deaths. The cost to the community is in excess of $720 million a year. The abnormality in asthma is not fully understood, however inflammation, changes to the structure of the airways and excessive airway narrowing are key factors. Inflammation and the allergic reactions which accompany asthma cause fluid to leak from tiny blood vessels in the lung. This fluid and the inflammation are linked to changes in the airway which include structural protein deposition - breakdown and an overgrowth of the smooth muscle that lines the walls of the airway. Our work is focussed on understanding the relationship between the structural protein deposition - breakdown and excess muscle growth. We also hope to gain a better understanding of the way asthma treatments combat these changes in the asthmatic airways.Read moreRead less
Hormonal Modulation Of Prostatic Growth And Contractility
Funder
National Health and Medical Research Council
Funding Amount
$324,237.00
Summary
With increasing age human males are likely to develop benign prostatic hyperplasia (BPH), a disorder characterized by urethral obstruction due to an increase in size of the prostate gland. Drug treatments of this condition are not entirely satisfactory and the current project is to examine the mechanisms by which the prostate grows and occludes the urethra. We will use human prostate cells grown in artificial conditions to determine which hormones alter the types of cells and especially examine ....With increasing age human males are likely to develop benign prostatic hyperplasia (BPH), a disorder characterized by urethral obstruction due to an increase in size of the prostate gland. Drug treatments of this condition are not entirely satisfactory and the current project is to examine the mechanisms by which the prostate grows and occludes the urethra. We will use human prostate cells grown in artificial conditions to determine which hormones alter the types of cells and especially examine those cells which can contract as these may be of critical importance in the urethral obstruction. We hypothesize that an enzyme called protein kinase C may be implicitly involved in both cell growth and contractile function and we will examine the role of protein kinase C with a view ultimately to develop drugs which may interfere with this process and therefore aid in non-surgical treatment of the condition.Read moreRead less
Mechanisms Of Action Of Neurochemicals And Modulators In Human Intestine: Changes In Disease
Funder
National Health and Medical Research Council
Funding Amount
$442,500.00
Summary
Inflammatory bowel disease (IBD) and idiopathic chronic constipation (ICC) are two serious gastrointestinal disorders, for which no effective medical treatment is known. We will investigate the hypothesis that abnormalities in the nerve chemicals found in the gut contribute to the aetiology of these diseases. Our studies will examine the sites of action (receptors) for these chemicals (neurotensin and acetylcholine) in the small and large intestine. The mechanisms governing motility changes in r ....Inflammatory bowel disease (IBD) and idiopathic chronic constipation (ICC) are two serious gastrointestinal disorders, for which no effective medical treatment is known. We will investigate the hypothesis that abnormalities in the nerve chemicals found in the gut contribute to the aetiology of these diseases. Our studies will examine the sites of action (receptors) for these chemicals (neurotensin and acetylcholine) in the small and large intestine. The mechanisms governing motility changes in response to these chemicals have been well studied in animal intestine, but there is little detailed information from the human intestine. This study will provide insight into the mechanisms operating in the normal bowel, providing a base for comparing bowel obtained from patients with IBD or ICC. We will also study bowel removed at surgery for acute diverticular disease (DD), representing another type of inflammation. Studies on isolated segments of colon from ICC patients will determine whether the contractility of the muscle is abnormal in general or only with respect to the chemicals under investigation. Other studies will investigate the inflammatory processes occurring in the bowel and whether this differs in IBD. Our work will facilitate understanding of the function of the bowel in health and in gastrointestinal disorders and may lead to new medical treatments for IBD and ICC.Read moreRead less
Neurochemicals In The Control Of Human Bladder Function
Funder
National Health and Medical Research Council
Funding Amount
$196,018.00
Summary
The problem of urinary incontinence has received little attention from the medical and scientific research community until the last 10-15 years. Urinary incontinence can cause severe distress and is a taboo subject, even though it affects 30-40% of women. Public figures speak out about their experiences with breast cancer or heart disease, but not about leakage of urine. Elderly people with incontinence are forced into nursing homes, with major costs to the community. Incontinence is a major cli ....The problem of urinary incontinence has received little attention from the medical and scientific research community until the last 10-15 years. Urinary incontinence can cause severe distress and is a taboo subject, even though it affects 30-40% of women. Public figures speak out about their experiences with breast cancer or heart disease, but not about leakage of urine. Elderly people with incontinence are forced into nursing homes, with major costs to the community. Incontinence is a major clinical problem: although over 800 new patients per annum are seen at our Pelvic Floor Unit, the waiting time for a first appointment is 14-15 weeks. There are four main types of urine leakage: - stress incontinence (weak pelvic floor muscles); - overflow incontinence (seen in men with prostatic hypertrophy); - sensory urgency (frequent, uncomfortable desire to urinate); and - detrusor instability (bladder muscle spasms with leakage). We are primarily interested in detrusor instability and sensory urgency, which cause 35% of incontinence in general, but up to 85% of cases in the elderly. Patients suffer from an urgent desire to visit the toilet frequently, and may leak urine if they cannot reach the toilet quickly. Unlike stress incontinence, it cannot be corrected by pelvic floor surgery. Drug treatment is often unsuccessful, with many unacceptable side effects. In our research group, we have found that the sensory nerve which convey the sensation of bladder fullness, are overabundant and display increased amounts of neurochemicals. Our studies in isolated bladder muscle from these patients have shown abnormalities in responsiveness. Thus bladder from women with urge incontinence is resistant to drugs which abolish contraction in normal bladder. In this project we plan to find out why such changes occur. We will use new techniques to study bladder nerves and the receptors which convey the message to contract the bladder muscle.Read moreRead less