Thirst And Vasopressin Secretion In Left Ventricular Dysfunction
Funder
National Health and Medical Research Council
Funding Amount
$130,950.00
Summary
Water homeostasis is essential for life and is achieved by a balance between water intake, controlled by thirst, and output controlled by the kidneys via the hormone vasopressin. In health the control mechanisms of thirst and vasopressin are very similar. Both are controlled by the brain. Thirst and vasopressin secretion are activated when the body becomes dehydrated or when blood volume is low. Heart failure occurs when the heart cannot pump sufficient blood to meet the body's demands. It has a ....Water homeostasis is essential for life and is achieved by a balance between water intake, controlled by thirst, and output controlled by the kidneys via the hormone vasopressin. In health the control mechanisms of thirst and vasopressin are very similar. Both are controlled by the brain. Thirst and vasopressin secretion are activated when the body becomes dehydrated or when blood volume is low. Heart failure occurs when the heart cannot pump sufficient blood to meet the body's demands. It has a worse outlook than many cancers including breast and prostate cancer. Because the body's demands for oxygen are not being met, the body reacts as though blood volume is low. A variety of responses lead to excess body water with congestion of various organs and oedema. The aim of this research is to explore to what extent and how, the controls of thirst and vasopressin secretion are altered in heart failure by investigating both a rat model of heart failure and patients after a heart attack. From these studies we will gain a greater understanding of how body water homeostasis control mechanisms are altered which will aid our understanding of potential treatment options for this deadly disease.Read moreRead less
IDENTIFICATION OF BRAIN NEURONS INVOLVED IN THE CARDIOVASCULAR RESPONSE TO FEAR AND FLIGHT
Funder
National Health and Medical Research Council
Funding Amount
$400,247.00
Summary
The circulatory system of the body acts in concert with the respiratory system to distribute oxygenated blood to the brain and other organs and tissues of the body. Control of blood pressure and heart rate is achieved largely through the actions of the central nervous system on effector organs and tissues such as the heart and blood vessels. This control is exerted through the actions of nerves in the body which affect the rate and force of contraction of the heart and the diameter of blood vess ....The circulatory system of the body acts in concert with the respiratory system to distribute oxygenated blood to the brain and other organs and tissues of the body. Control of blood pressure and heart rate is achieved largely through the actions of the central nervous system on effector organs and tissues such as the heart and blood vessels. This control is exerted through the actions of nerves in the body which affect the rate and force of contraction of the heart and the diameter of blood vessels which restrict the flow of blood to the tissues. These nerves, in turn, are under the control of brain cells or neurons which are located in the brainstem. Blood pressure-controlling neurons, acting upon information they receive from pressure sensors in the major blood vessels in the chest cavity, can alter their activity so that blood pressure is maintained within normal limits. Our laboratory has been examining the properties of these blood pressure-controlling neurons by recording their minute electrical discharges and by studying other brain regions which are able to influence them. In this study, we will use newly-developed procedures which will allow us to identify the precise locations of these neurons in the brain, to study which neurotransmitters (chemicals released by neurons which are used to communicate with other neurons) they use, as well as to identify other regions of the brain they connect with and influence. The major significance of this work will be that new brain circuits which transmit information about the status of the cardiovascular system to other areas of the brain will be identified. Our understanding of, and the development of new treatments for, cardiovascular diseases such as high blood pressure and heart failure are critically dependent on advancing our understanding of the nervous system.Read moreRead less
Heart failure is a severely debilitating condition with a poor prognosis. It is characterized by retention of fluid and high nervous activity especially to the kidneys and the heart. Even with the best current treatment available, patients with heart failure still suffer from abnormally high nerve activity to the further detriment of this condition. The successful completion of this project will provide considerable insight into the role of the brain in the elevated nerve activity in heart failu ....Heart failure is a severely debilitating condition with a poor prognosis. It is characterized by retention of fluid and high nervous activity especially to the kidneys and the heart. Even with the best current treatment available, patients with heart failure still suffer from abnormally high nerve activity to the further detriment of this condition. The successful completion of this project will provide considerable insight into the role of the brain in the elevated nerve activity in heart failure. It will also provide us with a significant understanding of the role in reflex sympathetic nerve regulation of an important brain region known as the hypothalamic paraventricular nucleus (PVN). Our findings will help us understand the nature of the neurotransmitters contributing to the reflex nerve regulation and the specific neurons within the PVN involved. This knowledge could help us to identify novel potential therapeutic targets within the brain to alleviate the problems observed in heart failure.Read moreRead less
Forebrain Control Of Cardiovascular Function: Integrative And Cellular Mechanisms
Funder
National Health and Medical Research Council
Funding Amount
$834,233.00
Summary
Blood pressure is controlled to a large extent by nerves, known as sympathetic nerves, that supply the heart and blood vessels. Measurements in humans have shown that the activity of sympathetic nerves is increased in a number of cardiovascular diseases, including heart failure and in many cases of high blood pressure. This has the effect of constricting blood vessels and increasing heart rate, which places an additional load on the heart which can cause damage to the heart. It is not known what ....Blood pressure is controlled to a large extent by nerves, known as sympathetic nerves, that supply the heart and blood vessels. Measurements in humans have shown that the activity of sympathetic nerves is increased in a number of cardiovascular diseases, including heart failure and in many cases of high blood pressure. This has the effect of constricting blood vessels and increasing heart rate, which places an additional load on the heart which can cause damage to the heart. It is not known what causes this increased sympathetic activity, but one possibility is that it is due to the action of a circulating hormone called angiotensin, which acts on the brain, activating central nerve pathways which ultimately increase sympathetic activity. In this project we aim to test this hypothesis and thus help to unravel the mechanisms involved in the long term control of sympathetic activity and blood pressure.Read moreRead less