Neural Mechanisms Mediating Hypersecretion And Motility Patterns Induced By Enterotoxins
Funder
National Health and Medical Research Council
Funding Amount
$415,250.00
Summary
This project aims to identify the nerve cells that are responsible for the massive oversecretion of water and salt seen with cholera and other diseases producing diarrhoea. Many of these disease act through specific toxins and, although the biochemical targets of these toxins are reasonably well understood, the nerve cells on which they act have never been identified. Furthermore, the mechanisms that couple the oversecretion with a massive increase in the propulsive activity of the intestine are ....This project aims to identify the nerve cells that are responsible for the massive oversecretion of water and salt seen with cholera and other diseases producing diarrhoea. Many of these disease act through specific toxins and, although the biochemical targets of these toxins are reasonably well understood, the nerve cells on which they act have never been identified. Furthermore, the mechanisms that couple the oversecretion with a massive increase in the propulsive activity of the intestine are also unknown. We will investigate each of these questions using the small intestine of the guinea-pig, because the nerve circuit in this preparation is better understood than that of any other. Nerve cells that respond to three specific toxins, each known to activate the nervous system via different mechanisms, will be determined using intracellular recording methods, injection of marker dyes and methods that allow the identification of their neurochemistry. This will allow the functions of responsive nerve cells to be identified and their places in the circuits that control secretion and propulsion to be determined. This information will be correlated with studies in whole animals being undertaken in Sweden so that potential sites for intervention can be identified.Read moreRead less
Neural Coordination Of Intestinal Motility And Mucosal Secretion Of Water And Salt - Role In Toxin Induced Diarrhoea
Funder
National Health and Medical Research Council
Funding Amount
$490,020.00
Summary
This project deals with some of the basic mechanisms underlying disorders of gastrointestinal function and in particular with the mechanisms responsible for diarrhoea. Whenever there is a natural disaster (the recent tsunami for example) or a war, the breakdown of medical services leads to concern about outbreaks of cholera and other diarrhoea causing diseases, so understanding the mechanisms by which the cholera bacterium cause diarrhoea remains a major imperative. It is known that the diarrhoe ....This project deals with some of the basic mechanisms underlying disorders of gastrointestinal function and in particular with the mechanisms responsible for diarrhoea. Whenever there is a natural disaster (the recent tsunami for example) or a war, the breakdown of medical services leads to concern about outbreaks of cholera and other diarrhoea causing diseases, so understanding the mechanisms by which the cholera bacterium cause diarrhoea remains a major imperative. It is known that the diarrhoea resulting from cholera infection is produced by an enterotoxin, which acts to produce a massive over-secretion of water and salt through the intestinal wall, which if it is not controlled causes death by dehydration. This effect requires the activity of the nerve cells within the gut wall, the enteric nervous system (ENS). Other bacterial toxins have similar effects and also require activity of the ENS for these effects to be manifested. This project will identify how these toxins alter the activity of the ENS and the effects that they have on intestinal movements which are also regulated by the ENS. We already know that the movements and secretion of water are related to each other and that this relationship is disturbed in some more subtle diseases like irritable bowel syndrome. This project will characterise this relationship, thereby shedding light on the physiology underlying a variety of gastrointestinal disorders.Read moreRead less