The John B Pierce Laboratory, New Haven, CT 06519, USA.
Physiol Behav. 2012 Jun 6;106(3):394-9. doi: 10.1016/j.physbeh.2012.02.026. Epub 2012 Mar 3.
Post-ingestive factors are known to strongly modulate feeding behavior by providing feedback signals to the central nervous system on the current physiological state of the organism. Of particular interest is the identification of the physiological pathways that permit the brain to sense post-ingestive signals. We will review recent evidence supporting the concept that direct stimulation of the gastrointestinal tract with nutrients induces release of the catecholamine neurotransmitter dopamine. In addition, changes in dopamine efflux produced by direct stimulation of the gastrointestinal tract were found to reflect the caloric load of the infusates, suggesting that dopamine signaling may function as a central caloric sensor that mediates adjustments in intake according to the caloric density of a meal. Consistent with the above, blockade of dopamine signaling disrupts flavor-nutrient associations and impairs the regulatory capacity to maintain constant caloric intake during intra-gastric feeding. Future research must determine the exact pathways linking gut nutrient administration to dopamine efflux. Current evidence points to parallel contributions by pre- and post-absorptive pathways, indicating that dopamine systems constitute a site of convergence through which distinct physiological signals can exert control over ingestive behaviors.
进食后因素通过向中枢神经系统提供关于机体当前生理状态的反馈信号，强烈调节进食行为。特别感兴趣的是确定允许大脑感知进食后信号的生理途径。我们将回顾最近的证据，支持以下观点，即直接刺激胃肠道的营养素会诱导儿茶酚胺神经递质多巴胺的释放。此外，发现直接刺激胃肠道引起的多巴胺外流量变化反映了输注物的热量负荷，表明多巴胺信号可能作为中央热量传感器，根据膳食的热量密度调节摄入。与上述观点一致，阻断多巴胺信号会破坏味道-营养的关联，并损害在胃内喂养期间维持恒定热量摄入的调节能力。未来的研究必须确定将肠道营养素管理与多巴胺外排联系起来的确切途径。目前的证据表明，吸收前和吸收后途径的平行贡献，表明多巴胺系统构成了一个汇聚点，通过该汇聚点，不同的生理信号可以控制摄食行为。
