Cochlear Mechanisms Of Otoacoustic Emission Generation
Funder
National Health and Medical Research Council
Funding Amount
$311,989.00
Summary
Deafness, both congenital and acquired, is likely to be one of the major causes of disability in the Australian workforce, in young Australians, and in some categories of pre-term infants in the next decade or two. While not life-threatening, hearing impairment deprives individuals of one of their most basic social needs: the ability to communicate with others. Although little can be done to recover lost hearing, it is important to detect hearing loss as early as possible in order to reduce furt ....Deafness, both congenital and acquired, is likely to be one of the major causes of disability in the Australian workforce, in young Australians, and in some categories of pre-term infants in the next decade or two. While not life-threatening, hearing impairment deprives individuals of one of their most basic social needs: the ability to communicate with others. Although little can be done to recover lost hearing, it is important to detect hearing loss as early as possible in order to reduce further loss (by behaviour modification in the case of noise-exposed adults) and to provide hearing assistance in very young children so that they may be exposed to some degree of auditory experience at as early an age as possible. To this end, the phenomenon of otoacoustic emissions, or noises from the ear, now recognised for twenty years, is likely to become even more significant in the early years of the next millennium. Otoacoustic emissions were first demonstrated as very soft echoes re-emerging from the ear after a delay of ten milliseconds or so following a click stimulus. These echoes are sounds produced by the ear as it goes about its normal function and are lost if the hearing sensitivity of the individual is below normal. Several other forms of otoacoustic emissions have been discovered and rapidly applied to the testing of hearing so that today the technique of assessing hearing status in neonates and others unable to co-operate, as well as in diagnostic applications, is widespread. The application of the technique, however, has preceded a real understanding of what otoacoustic emissions are and how they are generated, and their widespread use at the moment is somewhat akin to a car repair industry which does not understand how an engine works. This proposal intends to investigate the basic mechanisms behind otoacoustic emissions in order to improve their efficiency and accuracy of clinical interpretation.Read moreRead less
Identification Of The Pain Pathway From The Rectum And Its Mechanisms Of Activation
Funder
National Health and Medical Research Council
Funding Amount
$566,931.00
Summary
Abdominal pain is one of the most common reasons why patients seek medical attention. It is now known that irritable bowel syndrome (IBS) is one of the major causes of abdominal pain, but the reason why people experience pain from the gut is not known. This project will identify which sensory nerves in the gut wall signal pain to the spinal cord during conditions that mimic IBS and the precise mechanisms that activate these sensory neurons during IBS-like inflammation will be investigated.
The Neural Control Of Serotonin Release From Intestinal Enterochromaffin (EC) Cells
Funder
National Health and Medical Research Council
Funding Amount
$117,187.00
Summary
Many functional gastrointestinal problems are believed to be caused by a disruption of the normal functioning of the nerves within the wall of the gut. These nerves are believed to receive information about the contents of the intestine from a specialised class of cell lining the inside wall of the gut called the enterochromaffin cell. The enterochromaffin cell does this job by modulating the release of the transmitter serotonin. In some disorders, like the Irritable Bowel Syndrome (IBS) which c ....Many functional gastrointestinal problems are believed to be caused by a disruption of the normal functioning of the nerves within the wall of the gut. These nerves are believed to receive information about the contents of the intestine from a specialised class of cell lining the inside wall of the gut called the enterochromaffin cell. The enterochromaffin cell does this job by modulating the release of the transmitter serotonin. In some disorders, like the Irritable Bowel Syndrome (IBS) which can affect the upper and lower intestine, the information that serotonin carries can become confused. Thus, the control of the release of serotonin from the enteroendocrine cell is an important process to understand in health and in disease. We will investigate this release directly in isolated tissues from guinea pig small and large intestine and from human large intestine. This study will examine the role of serotonin and the modulation of its release from the enterochromaffin cell. Problems with serotonin release may underlie disease, thus, understanding how this release is controlled will provide a foundation for new and specific therapies that target channels or receptors specific to the release of serotonin. These data could help to develop therapies for gastrointestinal problems such as the IBS, chronic intestinal pseudo-obstruction and gastro-oesophageal reflux disease. The release of serotonin is also intimately linked with the diarrhea associated with cholera and anti-cancer treatments. The proposed study will contribute to the ongoing development of specific therapies that block serotonin receptors on the nerve terminal and will lead to new therapies that compliment existing therapies by modulating the release of serotonin.Read moreRead less
The Knotty Problem Of Enterochromaffin Cells And Gastro-intestinal Function: Unravelling Cause And Effect
Funder
National Health and Medical Research Council
Funding Amount
$403,097.00
Summary
It is crucial to understand how the food we eat controls the secretions and movements of a healthy or a diseased gastrointestinal (GI) system. One way control is achieved involves the release of serotonin (5-HT) from the enterochromaffin cells present in the epithelial lining of the intestine. This is the subject of our proposal and our results will help us to understand the causes of GI disorders and help to formulate new treatments.
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.
The human brain has many subdivisions (�areas�) that are dedicated to vision, but in many cases their functions remain unclear. This project will study an area located deep in the brain, about which very little is known, and which appears to be affected from early stages in conditions such as Alzheimer�s disease. By understanding the patterns of electrical activity of cells in this region, and their connections with other brain areas, we hope to decipher their contribution to sensory cognition.
We are able to identify and discriminate objects in the world because of exquisitely detailed and rapid processing of sensory information by neurons in the cortex of the brain. In this project we will examine these operations in neurons in the cortex that receive input from the large face whiskers of the rat. These whiskers are used for fine-grain discrimination and for gauging distance. They are deflected by being actively moved, under muscle control, over objects (active touch) or by being pas ....We are able to identify and discriminate objects in the world because of exquisitely detailed and rapid processing of sensory information by neurons in the cortex of the brain. In this project we will examine these operations in neurons in the cortex that receive input from the large face whiskers of the rat. These whiskers are used for fine-grain discrimination and for gauging distance. They are deflected by being actively moved, under muscle control, over objects (active touch) or by being passively deflected by objects. Deflection results in inputs to the brain that are processed to form the neural basis for very finely detailed perceptual behaviour. In rats, with impoverished visual and auditory senses, the whiskers are the major sensory system for interacting with the world, and are used in navigating the environment and in finding and distinguishing foods. Thus they contribute strongly to the remarkable success of this species. This elegant sensory system has a number of advantages that make it a very good model for the study of brain mechanisms responsible for active fine-grain sensory function. We plan to take advantage of the unique features of this system to define the information processing that occurs in the cortex in this elegantly complex system. This will address an issue relevant to all sensory systems - namely the neural basis of complex fine grain perceptual behaviour. Understanding the mechanisms underlying active tactile perception also has relevance to clinical conditions involving deficits in active touch e.g., in diabetic polyneuropathy (which eventually affects ~50% of diabetics), in leprosy (in which an early sign is damage to active touch). Knowledge of the core brain processes in active touch gained in this study could eventually underpin the ameliorative technologies for such deficits.Read moreRead less
The Role Of Adipokines In Modulation Of Gastric Vagal Afferent Satiety Signals
Funder
National Health and Medical Research Council
Funding Amount
$624,535.00
Summary
When we feel full after a meal it is the result of a variety of different nerve signals from the gut in response to distension of the stomach and specific nutrients. These signals are disordered in obesity and may be influenced by factors released from fat stores in the body. The aim of this project is to determine how these factors interact with gastric nerve satiety signals and thus identify targets for the pharmacological treatment of obesity.