Neurocircuitry of a novel gastrointestinal-circulatory reflex

心脏输送到全身的血液中，有三分之一是通过胃肠道输送的。这意味着肠道循环在血压控制中起着重要作用。肠道血流量根据改变的行为活动所施加的需求而变化。参加体育锻炼会导致流向四肢工作肌肉的血液增加，并从肠道分流出去。或者，食物消费促进了流向肠道的血液流量的增加，以帮助消化。虽然这是一个正常的身体过程，但血流的重新分配也有不利的影响：在老年人中，对这些变化的补偿通常会受到损害，可能会导致低血压和晕厥。此外，进食后心绞痛的发生率更高，这可能与血液重新分配到肠道有关。胆囊素(CCK)是一种激素，由排列在肠道上的特殊细胞释放，在控制流向肠道的血液方面发挥作用。我们提出的假设是，CCK作用于神经，神经向大脑发送信号，进而通过其他神经作用，导致流向肠道的血液增加。这个项目旨在研究大脑中控制这一新机制的神经通路。我们将记录特定脑细胞和神经的活动，这些细胞和神经参与控制肠道的血液供应。我们还将研究大脑细胞和神经使用哪些化学物质来相互通信，从而建立一个参与肠道血液流动控制的大脑区域的模型。该项目将为肠道血流控制的机制提供新的线索，并确定相关的脑通路。这些信息将对老年人和肥胖者以及心绞痛患者的循环系统疾病和与食物消耗有关的心血管变化的治疗具有重要意义。

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.