The Role Of Prostaglandins In The Control Of Intestinal Motility In Physiological And Experimental Inflammatory States.
Funder
National Health and Medical Research Council
Funding Amount
$316,209.00
Summary
Many intestinal disorders are due to inflammations of unknown origin, associated with pain, diarrhoea or constipation. How this occurs is not known. The movements of the intestine are due to the contractions and relaxations of the muscular wall, which are controlled by a network of nerve cells, a kind of a brain in the gut. In inflammatory conditions, a multitude of chemical substances are produced by the sick gut. Among these substances are the prostaglandins that are responsible for increasing ....Many intestinal disorders are due to inflammations of unknown origin, associated with pain, diarrhoea or constipation. How this occurs is not known. The movements of the intestine are due to the contractions and relaxations of the muscular wall, which are controlled by a network of nerve cells, a kind of a brain in the gut. In inflammatory conditions, a multitude of chemical substances are produced by the sick gut. Among these substances are the prostaglandins that are responsible for increasing pain from inflamed parts. However, the gut makes prostaglandins even when there is no inflammation, although it is not clear what do these substances do in the normal intestine. During disease, prostaglandins are made in much larger amounts. If we can establish what they do normally we may be able to establish how they work in disease. Therefore our projects is in two parts. First, we will investigate how prostaglandins normally affect the working of the nerves and muscle controlling intestinal movement. In the second part we will reveal the role of these substances during mild inflammation induced in some laboratory animals to mimic human diseases. All experiments will be carried out on intestines removed from these experimental animals after they are killed humanely. This enables us to study how the experimentally induced diseases affect gut function, especially movement. We will use a method, that has recently been developed in our laboratory, to transform video recordings of gut movements into computer-generated maps. From these pictures, we can see patterns of movement that are too subtle to detect by just watching the videos. We will end our project by establishing if and when prostaglandins are responsible for producing the abnormal intestinal movements seen in disease. This will give clinicians a better basis to develop new drugs against gut disorders.Read moreRead less
Spatio-temporal Analysis Of Rat Intestinal Motility In Physiological And Disease Models
Funder
National Health and Medical Research Council
Funding Amount
$358,750.00
Summary
This project addresses the question of how the movements of the gut are controlled in health and disease. The progress of food along the gut is due to movements of the involuntary muscle of the wall of the intestine. Three fundamental mechanisms are involved. One is the spontaneous ability of the intestinal muscle to contract rhythmically and is driven by a delicate net of pacemaker cells. Fast propulsion of food contents depends on nerve circuits in the gut wall that generate a powerful pumping ....This project addresses the question of how the movements of the gut are controlled in health and disease. The progress of food along the gut is due to movements of the involuntary muscle of the wall of the intestine. Three fundamental mechanisms are involved. One is the spontaneous ability of the intestinal muscle to contract rhythmically and is driven by a delicate net of pacemaker cells. Fast propulsion of food contents depends on nerve circuits in the gut wall that generate a powerful pumping behaviour to prevent over-filling or to eject toxic or irritating substances (eg: some laxatives activate this mechanisms). This is often called peristalsis. A third mechanism consists of activity of nerve cells in the gut, that slowly propagates along the intestine and causes the muscle to contract, sweeping along any remnants. The movements generated by these three mechanisms occur in segments of intestine isolated from rats. The major difficulty up until now has been to relate the actual movements in living animals to these fundamental mechanisms. It is now possible to bridge this gap because we have developed methods to record, display and measure graphically the actual movements. Movements are transformed into spatio-temporal maps which show all of the contractions over a period of time. Coordinated activity is visible in these maps as recognisable patterns or visual objects. Measurements can be readily made with conventional statistics. The literature in gastroenterology is full of descriptions of motility based on indirect methods of recordings. In this project we will be able to correlate the previous indirect methods with the new graphic methods and thus establish a clearer, simpler and more accurate classification of normal patterns of intestinal motility. We will then use this to establish what goes wrong in a number of experimental diseases known to affect adversely the movements of the intestine.Read moreRead less
Inflammatory Bowel Disease (IBD) has two clinical forms known as Ulcerative Colitis (UC) and Crohn's Disease (CD). These are severe diseases which predominantly affect young people. They are occasionally fatal and often severely debilitating. Treatment of UC frequently requires removal of the large bowel and life long wearing of an ileostomy bag. While this is curative, its psychological and life style effects are very disturbing particularly in the young. The cause of IBD is unknown, although i ....Inflammatory Bowel Disease (IBD) has two clinical forms known as Ulcerative Colitis (UC) and Crohn's Disease (CD). These are severe diseases which predominantly affect young people. They are occasionally fatal and often severely debilitating. Treatment of UC frequently requires removal of the large bowel and life long wearing of an ileostomy bag. While this is curative, its psychological and life style effects are very disturbing particularly in the young. The cause of IBD is unknown, although it is clear that there are both genetic and environmental factors. We have developed a model of IBD in mice which appears to be very like human UC. We have generated genetically modified mice in which it appears that the mucous secreted by their bowel wall is different from normal. We propose to investigate how this change leads to UC. It appears likely that the mucous is defective and can not prevent some of the normal bacteria or other material present in the stools from entering the bowel wall and causing chronic inflammation. If we can show that this is the case, it adds strong support to the the idea that a similar genetic trait may occur in some humans and that this may be one of the genetic components which renders them susceptible to IBD. Put another way, it would be a pointer to the type of genetic defect which may underlie susceptibility in humans and so help to focus the search for the genetic component. Understanding genetic factors underlying disease susceptibility is vitally important to inform genetic counselling. In addition, understanding the various factors which lead to IBD is critical to developing rational treatments which target cause rather than the symptoms of the disease.Read moreRead less
Understanding The Role Of Nociceptin In PMNL-mediated Inflammation In Vivo
Funder
National Health and Medical Research Council
Funding Amount
$474,750.00
Summary
This work will study the role of a type of protein in white blood cell movement into tissues, a process called inflammation. The outcome of this work may lead to the development of molecules which control this movement of white blood cells more specifically than existing therapeutics. Such inhibitors would potentially be useful as anti-inflammatory agents in a range of human diseases.