Sensory pathways from the gastrointestinal mucosa

肥胖对澳大利亚人来说是一个迫在眉睫的健康危机;它增加了许多严重疾病的机会，包括糖尿病，癌症，中风和心脏病。当食物中消耗的能量大于长时间使用的能量时，就会发生肥胖。因为人类通常在每天的几顿饭中获得大部分食物，所以这些饭菜的大小非常重要。决定什么时候停止进食可以有效控制能量摄入。众所周知，到达肠道的营养物质会导致胃和肠内壁细胞释放激素。这些激素告诉大脑什么时候已经消耗了足够的食物。过去人们认为激素在血液中流动直接影响大脑。最近，人们已经清楚地认识到，它们的大部分作用实际上是由末端位于肠道内壁的感觉神经元来传递的。这些激素对感觉神经纤维有很强的作用，然后感觉神经纤维将迷走神经中的神经纤维中的电信号发送到大脑。它们在这里建立联系，最终影响控制进食的中枢。关于激素如何影响肠道壁中的感觉神经末梢，是否所有神经纤维都以同样的方式受到影响，以及向大脑传达何种信息，还有很多东西需要了解。该项目将使用电生理学方法来确定哪些神经纤维被激素激活，不同的激素是否影响不同的神经纤维，哪些营养素激活特定的神经纤维，以及神经纤维是否与特定的释放激素的细胞进行选择性接触。这些问题对于理解我们通常是如何停止进食的，以及药物是如何被设计成在每顿饭的早些时候引起饱腹感的非常重要。

Obesity is a looming health crisis for Australians; it increases the chances of many serious diseases including diabetes, cancer, stroke and heart disease. Obesity occurs when the amount of energy consumed in food is greater than the energy used over an extended period. Because human beings usually get most of their food in a few meals each day, the size of those meals is very important. Deciding when to stop eating can exert a powerful control on energy intake. It is well known that nutrients reaching the gut cause the release of hormones from cells in the lining of the stomach and intestine. These hormones tell the brain when enough food has been consumed. It used to be thought that the hormones travelled in the blood stream to affect the brain directly. Recently, it has become clear that much of their effect is actually carried by sensory neurons with endings in the lining of the gut. The hormones have a powerful effect the sensory nerve fibres which then send electrical signals in nerve fibres running in the vagus nerve to the brain. Here they make connections which eventually influence the centres that control feeding. There is much to understand about how hormones affect the sensory nerve endings in the wall of the gut, whether all nerve fibres are affected the same way and what sort of information is conveyed to the brain. This project will use electrophysiological methods to identify which nerve fibres are activated by hormones, whether different hormones affect different nerve fibres, which nutrients activate particular nerve fibres and whether nerve fibres make selective contacts with particular hormone-releasing cells. These questions are important for understanding how we normally stop feeding and how drugs might be designed to cause feelings of fullness earlier in each meal.