SWALLOWING--BUCCOPHARYNGEAL/ESOPHAGEAL COORDINATION

吞咽是一种更复杂的运动行为，由位于孤束核及其周围的延髓中央模式生成器集中编程。中枢模式生成器对神经元模式运动活动的产生和调节依赖于内源性的兴奋和抑制机制以及必要的中枢和外周传入接触。通过NMDA的兴奋和通过GABA受体的抑制的相对贡献的显著失衡可能形成了神经系统疾病存在的吞咽功能障碍的基础。以大鼠为动物模型，研究吞咽过程中对口咽和食道协调至关重要的兴奋和抑制过程的解剖学基础。伪狂犬病病毒的跨突触追踪结合：(1)荧光逆行追踪将在运动前神经元水平上研究颊咽和食道中枢模式生成器网络之间的解剖联系；(2)N-甲基-D-天冬氨酸(NMDA)受体亚单位(R1，R2a-D)和GABAA受体亚单位(α1-6，β1-3，Gamma1-3，Delta)的寡核苷酸探针原位杂交将用于确定我们的运动前神经元表达的NMDA和GABAA受体亚单位；(4)谷氨酸和GABA的免疫细胞化学将被用来确定构成并投射到中枢模式生成器的谷氨酸和GABA能神经元的位置和组织；(5)NMDAR1和GABAAα1受体亚单位的免疫细胞化学将被用来研究这两种受体在颊咽和食道前运动神经元上的共存(三标记法)。由于兴奋性和抑制性突触功能的改变可能与吞咽障碍的发病机制有关，这些研究可能对吞咽困难患者的未来临床治疗有直接影响。

Swallowing, one of the more complex motor behaviors is programmed centrally by a medullary central pattern generator located in and around the nucleus of the solitary tract. The generation and modulation of neuronal patterned motor activity by the central pattern generator is dependent upon endogenous excitatory and inhibitory mechanisms and requisite central and peripheral afferent contacts. A significant imbalance in the relative contribution of excitation via NMDA and inhibition via GABA receptors may form the basis of dysfunctional swallowing present in neurological disease. Utilizing the rat as animal model, the anatomic basis of the excitatory and inhibitory processes critical to the coordination of the buccupharyngeal and esophageal phases of swallowing will be studied. Transsynaptic tracing with Pseudorabies Virus in conjunction with: (1) Fluorescent retrograde tracing will be utilized to study the anatomical connections between the buccopharyngeal and esophageal central pattern generator networks at the premotor neuron level; (2) In situ hybridization with oligonucleotide probes for the different N-Methyl-D-aspartate (NMDA) receptor subunits (R1, R2A- D) and GABAA receptor subunits (alpha1-6, beta1-3, gamma1-3, delta) will be utilized to determine the NMDA and GABAA receptor subunits expressed by our premotor neurons; (4) Immunocytochemistry for glutamate and GABA will be utilized to determined location and organization of glutaminergic and GABAergic neurons constituting and projecting to the central pattern generator; (5) Immunocytochemistry for NMDAR1 and GABAA alpha1 receptor subunit proteins will be utilized to investigate colocalization of the receptors on buccopharyngeal and esophageal premotor neurons (triple labeling method). Since alterations in excitatory and inhibitory synaptic function could contribute to the pathogenesis of swallowing disorders, these studies may have a direct bearing on the future clinical management of patients with dysphagia.