Mechanisms Behind The Activation Of Cardiac And Renal Sympathetic Nerve Activity In Heart Failure
Funder
National Health and Medical Research Council
Funding Amount
$452,670.00
Summary
Heart failure is associated with an increase in messages from the brain that control how fast the heart beats but the factors involved remain poorly understood. This project will enable a better understanding ot the mechanisms controlling this increase in the activity of the nerves. This understanding will provide a new avenue for therapy and for the development of new treatments.
Mechanisms Controlling Sympathetic Nerve Activity To The Heart
Funder
National Health and Medical Research Council
Funding Amount
$101,220.00
Summary
In heart failure there is a large increase in sympathetic nerve activity to the heart and the kidney that has detrimental effects which is related to mortality in patients. The areas in the brain causing the increased nerve activity to the heart are unknown. We will investigate the role of two key brain areas in mediating this increase. In addition we will also focus on local mechanisms that are responsible for the increase in noradrenaline spillover.
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
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.
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
Control Of Sympathetic Nerves That Talk To The Immune System
Funder
National Health and Medical Research Council
Funding Amount
$385,958.00
Summary
The two complex systems of the body, the immune system and the nervous system, communicate with each other. This proposal studies one of the major pathways from brain to immune system - sympathetic immuno-efferent nerves. In stroke, these pathways cause profound immunosuppression, causing susceptibility to infection. Their poorly understood central and peripheral pathways will be defined and mapped by this study.
Hypothalamic Orexin Neurons And The Medullary Sympathoadrenal Centre: A Key Role In Glucose Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$577,957.00
Summary
Hypoglycaemia or low blood sugar is a major side-effect of the treatment of diabetes. Exposure to hypoglycaemia results in changes in the brain (neuroplasticity) that reduce the awareness of hypoglycaemia, often with serious consequences. Hypoglycaemia triggers the production of several hormones including adrenaline which restore normal blood glucose. This process is incompletely understood. This research project will identify key components of the neurocircuitry that controls blood sugar.
Hypertension is the major driver of cardiovascular disease affecting over a billion people. The cause is increasingly lifestyle related (obesity and stress) and activation of the nervous system is a major contributor in all cases. My vision for the next 5 years is discover the key underlying mechanisms within the central nervous system and the kidney that are primarily responsible for increasing nervous activity and blood pressure.
Reducing The Burden Of Orthostatic Intolerance - Delineating Mechanisms And Improving Therapy
Funder
National Health and Medical Research Council
Funding Amount
$411,735.00
Summary
Orthostatic intolerance (OI) represents a heterogenous group of complex disorders which are poorly understood and lack effective treatment. They are frequently disabling and may severely impact on quality of life. In the proposed project, we will undertake a systematic investigation of _sympathetic nervous system� in OI patients and assess the clinical effect of a drug _L-DOPS� in subjects suffering from OI.