SWALLOWING--BUCCOPHARYNGEAL/ESOPHAGEAL COORDINATION

吞咽是较为复杂的运动行为之一，是由位于孤立束核内及其周围的髓质中央模式发生器集中编程的。中枢模式产生器对神经元模式运动活动的产生和调节依赖于内源性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不平衡可能形成神经系统疾病中存在的功能障碍吞咽的基础。以大鼠为动物模型，研究咽咽吞咽和食管吞咽相协调的兴奋和抑制过程的解剖学基础。伪狂犬病毒跨突触示踪结合：(1)荧光逆行示踪将在运动前神经元水平上研究咽和食管中枢模式产生网络之间的解剖联系；(2)利用不同n -甲基-D-天冬氨酸（NMDA）受体亚基（R1, R2A- D）和GABAA受体亚基（alpha1-6, beta1-3, gamma1-3, delta）的寡核苷酸探针原位杂交，确定运动前神经元表达的NMDA和GABAA受体亚基；(4)谷氨酸和GABA的免疫细胞化学将用于确定谷氨酰胺能和GABA能神经元构成和投射到中枢模式发生器的位置和组织；(5)利用NMDAR1和GABAA α 1受体亚基蛋白的免疫细胞化学方法研究其在咽和食管前运动神经元上的共定位（三重标记法）。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，这些研究可能对未来吞咽困难患者的临床治疗有直接的影响。

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.