Neurocircuitry of a novel gastrointestinal-circulatory reflex

胃肠道接收大约三分之一的由心脏泵送到全身的血液。这意味着肠道循环在血压控制中起着重要作用。肠道血液流动的变化，根据所施加的要求改变的行为活动。参与体育锻炼会增加流向四肢工作肌肉的血液流量，并从肠道分流。或者，食物消耗促进血液流向肠道以帮助消化。虽然这是一个正常的身体过程，但也有血流重新分布的不利影响：在老年人中，这些变化的补偿往往受到损害，并可能导致低血压和昏厥。此外，与心绞痛相关的心脏疼痛的发生率在进食后更高，这可能与血流重新分布到肠道有关。胆囊收缩素（CCK）是一种从肠道特殊细胞释放的激素，在控制肠道血流中起作用。我们已经发展了这样一种假设，即CCK作用于神经，这些神经向大脑发送信号，而大脑又通过其他神经起作用，从而增加流向肠道的血液。该项目旨在研究大脑中控制这种新机制的神经通路。我们将记录参与控制肠道血液供应的特定脑细胞和神经的活动。我们还将研究脑细胞和神经使用哪些化学物质进行相互交流，从而建立一个参与肠道血流控制的大脑区域模型。该项目将为肠道血流控制机制提供新的线索，并确定相关的大脑通路。这些信息对于治疗老年人和肥胖者以及心绞痛患者的循环和食物消耗相关的心血管变化的疾病具有重要意义。

The gastrointestinal tract receives about one third of the blood pumped around the body by the heart. This implies that the gut circulation plays a major role in blood pressure control. Gut blood flow changes according to the demands imposed by altered behavioural activity. Engagement in physical exercise results in increased blood flow to the working muscles of the limbs and diversion away from the gut. Alternatively, food consumption promotes an increase in blood flow to the gut to aid digestion. While this is a normal bodily process, there are also adverse implications of the re-distribution of blood flow: in the elderly compensation for these changes is often impaired and can result in low blood pressure and fainting. In addition, the incidence of angina-related heart pain is greater after food consumption and this may be associated with re-distribution of blood flow to the gut. Cholecystokinin (CCK), a hormone which is released from special cells that line the intestine, plays a role in the control of blood flow to the gut. We have developed the hypothesis that CCK acts on nerves which send a signal to the brain which, in turn, acting through other nerves, produces an increase in the flow of blood to the gut. This project is designed to study the nerve pathways in the brain which control this novel mechanism. We will record the activity of specific brain cells and nerves which are involved in the control of the blood supply to the gut. We will also examine which chemicals the brain cells and nerves use for communication with each other and so build up a model of the brain areas which are involved in gut blood flow control. This project will shed new light on the mechanisms of gut blood flow control and identify the associated brain pathways. The information will be of importance in the treatment of diseases of the circulation and food consumption-related cardiovascular changes in the elderly and obese as well as in sufferers of angina.