Migratory Cells To Ganglionated Network: Self-organization Of The Enteric Nervous System
Funder
National Health and Medical Research Council
Funding Amount
$328,294.00
Summary
The intestine has its own nervous system. This develops from cells that wander into the intestine during early development and self-organize to form the functional nervous system . The correct organization of the cells of this nervous system is required for correct intestine function. How they self-organize is not known, and there are diseases in which the process is disturbed. Molecular and cell biology and mathematical modelling will be used to understand how this occurs.
Computational Study Of Selectivity, Gating And Mutation In The Acetylcholine Receptor And Potassium Channels
Funder
National Health and Medical Research Council
Funding Amount
$301,393.00
Summary
One way cells in living organisms communicate with each other is via the passage of charged particles across the cell membrane. This takes place through ion channels, large protein molecules that span the membrane and allow small molecules or ions to pass through a central pore. Malfunction of ion channels is known to underlie a variety of disorders including epilepsy, hypertension, kidney disease, heart attack, deafness. Channels also provide promising targets for making new broad spectrum anti ....One way cells in living organisms communicate with each other is via the passage of charged particles across the cell membrane. This takes place through ion channels, large protein molecules that span the membrane and allow small molecules or ions to pass through a central pore. Malfunction of ion channels is known to underlie a variety of disorders including epilepsy, hypertension, kidney disease, heart attack, deafness. Channels also provide promising targets for making new broad spectrum antibiotics and antivirals. This project aims to study two important types of ion channel: acetylcholine receptors that convey signals between nerve and muscle cells, and potassium channels that regulate the nerve impulses themselves. The binding of the neurotransmitter acetylcholine released from a nerve cell to acetylcholine receptors in the muscle cell prompts the opening of a cation conductive pore. The resulting influx of ions initiates a cascade of events ending in the contraction of the muscle fibre. However, the way in which this channel opening is initiated and how ions move into the muscle cell remain to be determined. Potassium channels are primarily used to rapidly 'switch off' nerve impulses so that subsequent messages can be passed through the nerve cell. To do this they have to be highly discriminatory, allowing only potassium to pass across the cell membrane and not sodium that would initiate another impulse. Although we now know what these tiny proteins look like, it is not clear how they differentiate between types of ions while still allowing many millions to pass each second. We will use computer simulations to study how these two type of channel open and close, and how they discriminate between different ion types. Using sophisticated computational techniques on Australia's most powerful supercomputers we aim to elucidate this fundamental area of human biology in the hope of deriving treatments for some debilitating neuromuscular diseases.Read moreRead less
How The Intestinal Microenvironment Controls Propulsion And Mixing Of Food In The Gut: Parallel Transduction Pathways
Funder
National Health and Medical Research Council
Funding Amount
$1,157,350.00
Summary
This project will identify the mechanisms that control the mixing of food with digestive juices, the absoprtion of nutrients from the gut to the blood stream and the excretion of waste. Disruption of these processes causes significant health problems and is associated with normal aging and many diseases. We will identify nutrients and other food components (eg spices) that switch gut from mixing to propulsion and hence identify targets to treat disorders of gut movement.
Role Of The Hypothalamus, Oxidative Stress And Angiotensin In Chronic Stress
Funder
National Health and Medical Research Council
Funding Amount
$535,333.00
Summary
Stress can trigger life threatening cardiovascular events and its impact is much greater when blood pressure is raised. We seek to determine which chemical type of brain neuron and which region is responsible for amplifying the responses to repeated stress in an animal model that closely resembles the human form of the disease. We will focus specifically on the hypothalamus which controls the sympathetic nervous system.
Investigations Of Neural Pathways For Heat Loss And Heat Gain In Thermoregulation And Fever
Funder
National Health and Medical Research Council
Funding Amount
$349,486.00
Summary
This project aims to map the nerve pathways in the brain that participate in the regulation of body temperature in the laboratory rat. The area of the brain that will be studied is the hypothalamic region. We will determine how this region influences the constriction of blood vessels in the skin to reduce heat loss when an animal is exposed to a cool environment, or when it exhibits a fever in response to a bacterial infection. As well, we will compare the nervous pathway that controls the gener ....This project aims to map the nerve pathways in the brain that participate in the regulation of body temperature in the laboratory rat. The area of the brain that will be studied is the hypothalamic region. We will determine how this region influences the constriction of blood vessels in the skin to reduce heat loss when an animal is exposed to a cool environment, or when it exhibits a fever in response to a bacterial infection. As well, we will compare the nervous pathway that controls the generation of heat from fat tissue in response to cold or fever with those controlling blood flow to the skin. These nervous pathways may be critical for maintaining correct body temperature during general anaesthesia, infections or in the aged subjected to temperature extremes. Thus, they are of importance in the health and well-being of much of the population.Read moreRead less
Forebrain Neuroadaptations To Chronic Morphine Treatment
Funder
National Health and Medical Research Council
Funding Amount
$435,956.00
Summary
Drug addiction is caused by long term changes in brain areas that normally produce the drives that sustain normal behaviours such as eating, drinking and sex. Addictive drugs effectively hijack these brain areas so that behaviours relating to drug taking become associated with feeling good. In some individuals, over time the pattern of drug taking becomes compulsive and no longer can be controlled. This transition is now known to be due to drugs causing physical changes to certain groups of nerv ....Drug addiction is caused by long term changes in brain areas that normally produce the drives that sustain normal behaviours such as eating, drinking and sex. Addictive drugs effectively hijack these brain areas so that behaviours relating to drug taking become associated with feeling good. In some individuals, over time the pattern of drug taking becomes compulsive and no longer can be controlled. This transition is now known to be due to drugs causing physical changes to certain groups of nerve cells in the brain. The affected nerve cells are responsible for causing new behaviours that appear once addiction is established. Addiction is not exclusive to humans. Animals will self-inject the same addictive drugs that humans use, and show many other kinds of addictive behaviours that parallel aspects of human addiction. Studying the effects of addictive drugs on rats and other animals has been very important in working out where and how drugs work. We now have a very good idea of which parts of the brain are affected by drugs, and it turns out that most addictive drugs act in the same places. We also now know for all of the major drugs, exactly which parts of nerve cells they affect. However, this turns out to be only the first step as the nerve cells that directly respond to drugs can affect other whole networks of nerve cells. This study is going to look at how morphine, a drug that is related to heroin, affects nerve cells in a part of the brain that helps cause addiction. It is going to work out which of the many pathways in this brain region are affected by morphine treatments that cause addiction in rats. It will then see what is happening to single nerve cells in the affected pathways. If we can understand more about these processes it may become possible to come up with new ways to treat addiction. We will also understand much more about the production of powerful emotional and behavioural drives so many of us find hard to control.Read moreRead less
Role Of SOCS 3 In Regulating Oligodendroglial Phenotype In Health And Disease
Funder
National Health and Medical Research Council
Funding Amount
$419,187.00
Summary
The response of nerve cells, known as oligodendrocytes, to an inflammatory insult dictates the severity of demyelinating diseases such as multiple sclerosis (MS). We have previously discovered that a key protein in this response is the cytokine leukaemia inhibitory factor (LIF) which, by activating the LIF receptor expressed on these cells, limits their death and reduces the clinical impact on animal models of MS. However, the therapeutic benefit of LIF is incomplete and we do not completely und ....The response of nerve cells, known as oligodendrocytes, to an inflammatory insult dictates the severity of demyelinating diseases such as multiple sclerosis (MS). We have previously discovered that a key protein in this response is the cytokine leukaemia inhibitory factor (LIF) which, by activating the LIF receptor expressed on these cells, limits their death and reduces the clinical impact on animal models of MS. However, the therapeutic benefit of LIF is incomplete and we do not completely understand the mechanisms by which LIF exerts these effects. To maximise the treatment potential of LIF we need to understand how LIF receptor signaling is modulated in the nervous system. An important protein known to regulate the activity of LIF and of other cytokines in other organs of the body is the suppressor of cytokine signaling 3 (SOCS 3) molecule. We have recently shown that the expression of SOCS 3 is increased in an animal model of MS, indicating that it is likely to modulate the activity of LIF in this context. We plan to investigate the nature of this regulation. SOCS 3 might limit the efficacy of LIF but it could also limit the deleterious effect of unbridled LIF receptor signaling. To distinguish between these possibilities, we plan to study the impact of demyelinating disease in animals in which SOCS 3 is either deleted or overexpressed in oligodendrocytes. In this way, we should be able to learn how to optimise the therapeutic potential of LIF in MS and related nervous system diseases.Read moreRead less
Brain Pathways For Neurally-mediated Fever: From Vagal Afferent To Sympathetic Output To Brown Adipose Tissue Via Brain
Funder
National Health and Medical Research Council
Funding Amount
$405,223.00
Summary
Fever is one of the immune defence reactions to the invasion of microorganisms such as bacteria and viruses. Fever reflects increased heat production and decreased heat loss. Systems regulating heat production and heat loss are under brain control. To trigger fever, the immune system must alert the brain to the presence of infection. The general view of how the alerting system triggers fever is that it develops in sequential steps. Macrophages ingest microorganisms, and then regulatory proteins ....Fever is one of the immune defence reactions to the invasion of microorganisms such as bacteria and viruses. Fever reflects increased heat production and decreased heat loss. Systems regulating heat production and heat loss are under brain control. To trigger fever, the immune system must alert the brain to the presence of infection. The general view of how the alerting system triggers fever is that it develops in sequential steps. Macrophages ingest microorganisms, and then regulatory proteins (cytokines) are released. The cytokines enter the blood stream and are transported to the brain. Recently, the existence of another signalling pathway has been demonstrated. The pathway is via a special peripheral sensory nerve, the abdominal vagal sensory nerve. However, special neural pathways in the brain have not yet been clarified, even though several neural relay stations have been proposed. To elucidate neural pathways transmitting information of infection to the brain, both input and output of the pathway need to be specified. Specific outputs other than body temperature have not been determined, so far. I have recently developed a new reflex model, in which I focus on sympathetic nerves supplying the specialised fat tissue as an output as well as the vagus sensory nerve as an input. The fat tissue, brown adipose tissue (BAT), generates heat. When the vagus sensory nerve is stimulated electrically, BAT sympathetic nerve is activated. We were very exited when we discovered the potency of the combination in our rat model. We are now ready to elucidate brain pathways for neurally-mediated fever, using our new reflex model. Signalling to the brain via the nervous system is faster than via the blood stream, and thus must be very important for the earliest phase of fever. Understanding the neural pathways by which the brain perceives peripheral infection and triggers fever may promote beneficial aspects of the acute-phase immune reaction.Read moreRead less