INTEGRATION OF TASTE AND VISCERAL AFFERENT SIGNALS

来自口腔和肠道的信号在中枢神经系统相互作用，以调节摄取。在口腔中，味觉刺激最初会影响摄取决定，也会促进持续摄取。在肠道中，化学感受器和机械感受器发出饱腹感的信号，从而帮助抑制进一步的摄入。行为学研究表明，摄取的特点是摄取后积累的负荷产生的抑制影响，逐渐抵消味觉对促进摄取的兴奋影响。这种味觉-内脏传入整合的机制在很大程度上尚不清楚，但可能涉及神经信号到达特定的腹侧神经系统部位，包括臂旁核(PBN)，该部位接受二级味觉和内脏传入的强烈汇聚投射。本系列实验将通过确定(1)胃和肠道机械感受器信号是否会聚并调节PBN中的味觉敏感神经元，以及(2)来自肝脏和十二指肠的代谢/营养相关信号是否也影响PBN中的味觉敏感神经元，来验证PBN是食物摄取调节的重要部位的假设。饮食、新陈代谢和胃肠紊乱会导致许多疾病，包括高血压、中风和糖尿病。了解味觉和内脏信号在大脑中的位置和方式是制定临床干预措施的基础。

Signals from the mouth and gut interact in the central nervous system to regulate ingestion. In the mouth, taste stimulation initially influences the decision to ingest and also promotes ongoing ingestion. In the gut, chemoreceptors and mechanoreceptors signal satiety, and thus help to suppress further intake. Behavioral studies show that ingestion is characterized by an inhibitory influence derived from an accumulating post-ingestive load that progressively counters the excitatory influence of taste on promoting ingestion. Mechanisms of this taste-visceral afferent integration are largely unknown, but likely involve neural signals reaching specific ventral nervous system loci, including the parabrachial nucleus (PBN), a site that receives strong convergent projects from second order taste and visceral afferents. The present series of experiments will test the hypothesis that the PBN is an important site for food intake regulation by determining (1) whether gastric and intestinal mechanoreceptor signals converge upon and modulate taste-sensitive neurons in the PBN, and (2) whether metabolic/nutrient-related signals from the liver and duodenum also influence taste-sensitive neurons in the PBN. Eating, metabolic and gastrointestinal disorders contribute to numerous diseases including hypertension, stroke and diabetes. An understanding of where and how taste and visceral signals are processed in the brain is fundamental to developing clinical interventions.