Central Control Of Stress-induced Changes In Immune Function.
Funder
National Health and Medical Research Council
Funding Amount
$411,724.00
Summary
LONG-TERM STRESS CAN ALTER OUR BRAIN'S ATTEMPTS TO FIGHT INFECTION Long-term stress is often blamed for causing illness but precisely how this occurs is now only beginning to be realised. It is especially disturbing that long-term stress can increase one's susceptibility to infections. Stress can alter the way our brain can help deal with assaults by bacteria and viruses. Normally, at the start of an infection, we release a hormone called cortisol from our adrenal glands. A low level of cortisol ....LONG-TERM STRESS CAN ALTER OUR BRAIN'S ATTEMPTS TO FIGHT INFECTION Long-term stress is often blamed for causing illness but precisely how this occurs is now only beginning to be realised. It is especially disturbing that long-term stress can increase one's susceptibility to infections. Stress can alter the way our brain can help deal with assaults by bacteria and viruses. Normally, at the start of an infection, we release a hormone called cortisol from our adrenal glands. A low level of cortisol in our body is beneficial because it can prevent the infection from taking hold in our body and spreading. However if we are chronically stressed our brains tell the adrenal glands to secrete excessive amounts of cortisol over long periods of time and this imbalance can actually hinder the ability of one's immune system to fight an infection. The unfortunate consequence is that the infection is more likely to win the battle and spread to cause further havoc. The present study will identify which areas of the brain are important in driving the secretion of cortisol during infection and how long-term stress can influence those areas. Because we might be exposed to long-term psychological stress that is repeated regularly or irregularly we will determine which pattern of stress has the greatest effect. An investigation into how the brain operates during long-term stress and infection will help us develop ways to prevent stress from disrupting our immune systems.Read moreRead less
Inhibition Of Fear Memories By Extinction: Neural Substrates.
Funder
National Health and Medical Research Council
Funding Amount
$234,250.00
Summary
Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relati ....Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relatively little is known about the mechanisms by which fear memories can be inhibited or suppressed. Understanding this latter process is a key to the development of effective treatments for anxiety disorders such as PTSD where the patient suffers from persistent, intrusive, unwanted trauma memories. A common experimental procedure for reducing learned fear is to repeatedly expose the subject to a fear-eliciting stimulus but without any aversive outcome. This procedure leads to a progressive loss, or extinction, of the fear reactions elicited by the stimulus. Historically, the extinction of fear was thought to be due to an erasure of the fear memory. However, recent evidence shows that extinction inhibits, rather than erases, the fear memory. Because the fear memories remain intact, some structure(s) in the brain must inhibit activity in the fear pathway. This project uses extinction of conditioned fear reactions in rat subjects to determine the structure(s) in the brain that inhibit fear memories and their behavioural and cardiovascular expression. It brings together the expertise of four well-established researchers and uses a combination of behavioural, physiological, immunohistochemical, tract tracing, and lesion approaches to achieve this aim. The proposed experiments will reveal the structure(s) in the brain that control the inhibition of fear, as well as the site(s) of this inhibition in the fear pathwayRead moreRead less
PREMOTOR SYMPATHETIC CONTROL OF BLOOD PRESSURE DURING PSYCHOLOGICAL STRESS: HYPOTHALAMUS VERSUS MEDULLA.
Funder
National Health and Medical Research Council
Funding Amount
$153,616.00
Summary
Health and well being depend in large part on a strong and efficient autonomic nervous system. The autonomic nervous system controls blood pressure, heart rate, gastrointestinal function, immune responses and certain forms of pain. Negative emotions can have a strong impact on autonomic function. We have all experienced the sweaty hands, pounding heart and intestinal discomfort when the mail arrives and bad news is expected or when we face a deadline for which we are not prepared. This is known ....Health and well being depend in large part on a strong and efficient autonomic nervous system. The autonomic nervous system controls blood pressure, heart rate, gastrointestinal function, immune responses and certain forms of pain. Negative emotions can have a strong impact on autonomic function. We have all experienced the sweaty hands, pounding heart and intestinal discomfort when the mail arrives and bad news is expected or when we face a deadline for which we are not prepared. This is known as psychological stress and it is usually associated with anxiety. Unfortunately, it is also the most common form of stress in modern urban life. There are clear indications that when these autonomic changes become chronic they can lead to hypertension, weak immune responses and gastric ulcers. In people already suffering from cardiovascular diseases they can also precipitate cardiac and cerebrovascular accidents. Clearly, the link between psychological stress and the autonomic nervous system needs to be explored in more detail. This project looks at the organization of the neural network in the brain and spinal cord that controls these responses. It uses a simple model of psychological stress in the conscious rat and recent non invasive techniques to record blood pressure and look at neuronal activity. We think that we have identified a group of neurons that may be controlling very specifically this response. It is located in the hypothalamus. The aim of this project is to further test the role of these neurons and find out what is controlling them. They will also be compared to another group of neurons that also controls blood pressure but apparently not in relation to psychological stress. The possibility that the cardiovascular response to psychological stress might be mediated by a specific group of neurons in the brain is a very exciting finding. It could lead to new therapeutic applications for acting against the short and long term effects of stress.Read moreRead less
Characterisation Of Antioxidant Pathways Involving Gpx-1: Implications For Neural Ischemic Reperfusion Injury.
Funder
National Health and Medical Research Council
Funding Amount
$458,250.00
Summary
Neural damage following stroke can be grouped into two stages. The first occurs immediately following the ischemic insult and results in the rapid loss of neural cell viability; the second stage (which usually results in severe neural dysfunction) occurs over many hours following reperfusion. There is however, a window of opportunity shortly following the ischemia-reperfusion where damage to the brain can be minimized if appropriate therapeutic intervention was available. However, our ability to ....Neural damage following stroke can be grouped into two stages. The first occurs immediately following the ischemic insult and results in the rapid loss of neural cell viability; the second stage (which usually results in severe neural dysfunction) occurs over many hours following reperfusion. There is however, a window of opportunity shortly following the ischemia-reperfusion where damage to the brain can be minimized if appropriate therapeutic intervention was available. However, our ability to identify novel targets and devise strategies for the treatment of stroke relies on our understanding of (a) the molecular processes that are initiated following brain ischemia and (b) the delayed molecular events that follow reperfusion and hypoperfusion and result in extensive neuronal loss. A major component that accompanies stroke is the generation of oxidative stress. Reactive oxygen species (ROS) are thought to make a significant contribution to neuronal cell injury and death during both the early and late stages following ischemia. Therefore the molecular pathways that are involved in ROS generation are prime targets for the development of improved therapies. It has already been established by us that the antioxidant enzyme, glutathione peroxidase-1 (Gpx-1) is essential in protecting neurons from ischemic injury-death. A clearer understanding of how Gpx-1 confers this protection in vivo would make an important contribution towards the design of improved treatments. In this proposal, we plan to determine the role of Gpx-1 in an in vivo model of stroke to: (1) demonstrate in a broader sense the functional importance of this antioxidant enzyme in neuronal survival and (2) to demonstrate in a more specific manner, the impact of this enzyme on two signaling molecules, PI3kinase (PI3K) and NFkB (both of which are redox sensitive and play important roles in neuronal cell viability) and their relevance to ischemic cell injury and death.Read moreRead less
NOVEL THERAPIES FOR ALZHEIMER'S DISEASE BASED ON A-BETA - METAL INTERACTIONS
Funder
National Health and Medical Research Council
Funding Amount
$461,443.00
Summary
The genetic data clearly show that the amyloid protein (A-beta) is central to the brain damage which occurs in Alzheimer's disease (AD). However exogenous or environmental factors involved in regulating its toxic actions are not understood. We have shown that the metals zinc and copper have dramatic effects on the properties of A-beta and that chemicals which alter the amounts of these metals in the brain may be useful in treating the disease. In this project we are investigating the ability of ....The genetic data clearly show that the amyloid protein (A-beta) is central to the brain damage which occurs in Alzheimer's disease (AD). However exogenous or environmental factors involved in regulating its toxic actions are not understood. We have shown that the metals zinc and copper have dramatic effects on the properties of A-beta and that chemicals which alter the amounts of these metals in the brain may be useful in treating the disease. In this project we are investigating the ability of one such compound to affect the metabolism of A-beta in a mouse model of AD.Read moreRead less
PURINERGIC TRANSMISSION AND CENTRAL AUTONOMIC REGULATION
Funder
National Health and Medical Research Council
Funding Amount
$157,848.00
Summary
The brain regulates bodily functions in a complex manner. One such example is the regulation of blood pressure and heart rate. This is achieved by an interconnected network of brain nuclei that sense information from the major blood vessels and integrate appropriate responses to maintain the status quo. Chemicals called neurotransmitters convey the nervous messages, and one such example is purines, which include ATP and adenosine. Both ATP and adenosine can act in a number of brain regions to mo ....The brain regulates bodily functions in a complex manner. One such example is the regulation of blood pressure and heart rate. This is achieved by an interconnected network of brain nuclei that sense information from the major blood vessels and integrate appropriate responses to maintain the status quo. Chemicals called neurotransmitters convey the nervous messages, and one such example is purines, which include ATP and adenosine. Both ATP and adenosine can act in a number of brain regions to modulate blood pressure and heart rate. This project is designed to characterise the mechanism by which purines act within specific brain nuclei to regulate the cardiovascular system. Considering the large economic burden on the healthcare system caused by cardiovascular disease, this research is vital to increase our understanding of how diseases such as hypertension may be caused, and therefore provide improved therapeutic strategies.Read moreRead less
Relaxin-3 Systems In Brain: Neurophysiology And Behaviour
Funder
National Health and Medical Research Council
Funding Amount
$287,321.00
Summary
The project aim is to better understand the function of a newly-discovered signalling molecule in the mammalian brain, know as relaxin-3. Recent research suggests that this chemical is vital for normal animal behaviour, such as arousal, stress, and learning and memory processes. This project will thoroughly characterise how this chemical modulates activity of brain regions that subserve behaviour in rats. This should reveal clinical implications of relaxin-3 in human behavioural disorders.