The Role Of Coronary Artery Baroreceptors In Cardiopulmonary Reflexes
Funder
National Health and Medical Research Council
Funding Amount
$361,018.00
Summary
The blood vessels and heart contain sensors that report on the state of the circulation to the brain. Blood vessel sensors send information about the level of blood pressure to the brain, and the brain coordinates appropriate changes in the activity of the heart and blood vessels so that blood pressure stays within narrow limits and blood flow to the brain is protected. Heart sensors send information to the brain about pressures in the heart and the release of chemicals during heart pain. Specia ....The blood vessels and heart contain sensors that report on the state of the circulation to the brain. Blood vessel sensors send information about the level of blood pressure to the brain, and the brain coordinates appropriate changes in the activity of the heart and blood vessels so that blood pressure stays within narrow limits and blood flow to the brain is protected. Heart sensors send information to the brain about pressures in the heart and the release of chemicals during heart pain. Specialized pressure receptors, like the receptors on blood vessels, have recently been reported to exist on the main blood vessels in the heart and, although not extensively studied, likely send information to the brain to participate in blood pressure regulation and to protect the supply of blood to the heart. These heart receptors normally work in concert with, and overshadowed by, the blood vessel receptors. In cardiovascular disease this concerted and complimentary interaction may be lost, resulting in contradictory signals being sent to the brain and inappropriate regulatory responses occurring. To study the functions of these heart receptors we will compare the number and types of nerves going to the heart receptors with the nerves that go to the blood vessel receptors to tell us whether their functions are likely to be similar. We will activate the heart receptors in healthy conscious animals to see what happens to blood pressure, heart rate, breathing patterns and blood flow to different organs. Finally we will use brain mapping techniques to see which brain cells are excited when the heart receptors are excited, and brain cell recording techniques to determine how individual brain cells respond to heart or vessel information. These studies will provide important new information about heart sensors, and help us understand the role these sensors have in heart disease or heart attack. This knowledge will aid the development of effective new ways of treating heart disease.Read moreRead less
THE VASCULAR CONSEQUENCES OF SNORING AND OBSTRUCTIVE SLEEP APNOEA
Funder
National Health and Medical Research Council
Funding Amount
$476,052.00
Summary
Snoring refers to a condition where the throat narrows significantly during sleep, and allows the soft tissues which surround this part of the airway to vibrate and create the typical snoring noise. Habitual snoring is a very common problem in the adult population, with a prevalence of between 20-40%. More severe forms of snoring are associated with the obstructive sleep apnoea syndrome, which is a condition in which the throat completely blocks behind the tongue and palate during sleep leading ....Snoring refers to a condition where the throat narrows significantly during sleep, and allows the soft tissues which surround this part of the airway to vibrate and create the typical snoring noise. Habitual snoring is a very common problem in the adult population, with a prevalence of between 20-40%. More severe forms of snoring are associated with the obstructive sleep apnoea syndrome, which is a condition in which the throat completely blocks behind the tongue and palate during sleep leading to cessation of breathing for short periods of time. Sleep apnoea is among the commonest chronic disorders of adult males occurring in 5% of men over the age of 45 years. Increasingly, it is now recognised that snoring, without sleep apnoea, may be an independent risk factor for the development of both of these very common and significant medical disorders. However, there have been no studies exploring the mechanisms by which snoring might contribute to the development of stroke and hypertension. In this proposal, we will explore the hypothesis that chronic snoring transmits a pressure wave through the tissues of the neck to the carotid artery which is the main blood supply to the brain. We propose that the chronic vibration of this artery leads to disease such as atherosclerosis and hypertension. Our studies will help to prove that this is a common mechanism whereby both snoring and sleep apnoea may contribute to the development of important vascular diseases. Studies will also establish the prevalence of carotid atherosclerosis in snorers (with and without OSA), and the prevalence of habitual snoring and OSA in patients at risk of developoing completed stroke. The recognition of snoring as an independent risk factor for vascular disease will clearly have important and wide ranging implications for the future management of snoring in the prevention of stroke and hypertension.Read moreRead less