REGULATION OF TASTE GENERATION

味觉为再生研究提供了一个模型系统，因为 受体细胞的持续周转及其营养依赖 味觉神经的神经支配。对该项目的研究表明， 一些细胞表面分子在味觉上有不同的表达 细胞，这种表达依赖于味觉的神经支配 神经纤维。第一个具体目标是确定 这些分子的表达与味觉细胞类型之间的关系 这种表达是由支配神经或味觉决定的。 上皮组织。EM免疫细胞化学将解决两者之间的关系 NCAM、L1、几种血型抗原和其他碳水化合物来品尝 单元类型。上皮细胞和神经支配在血管内皮损伤中的作用 味觉细胞表型的确定将通过特性进行评估 交叉神经支配后的瓣状和菌状味蕾 鼓索(CT)神经或前舌的舌后 被第IXth神经攻击。第二个具体目标是确定可塑性 孤束核中的中央味觉联系 (NST)在味蕾去神经和再神经支配之后。这个 第一个实验将评估中枢神经系统对去神经的反应。初步 研究表明味觉神经后NST内有强烈的神经胶质反应 以及GAP-43和GAP-43的显著结构性表达 NST中的星形胶质细胞和小胶质细胞标志物。这意味着持续不断的 中枢神经系统的重组伴随着正常的味觉细胞更新。这个 终末变性和反应性胶质化的程度和时间进程 周围神经损伤后的铜-银研究 小胶质细胞(OX42)和星形胶质细胞的变性方法和抗体 (GFAP)。再生将使用抗体进行评估。 再生轴突(GAP43和CDA-1)。高尔基方法将被用来 描述味觉神经损伤对NST细胞的影响。一秒钟 一系列研究将审查终端领域的重组 (A)IXth神经挤压后再生的IXth神经轴突，(B)IXth 神经挤压合并膝状神经节破坏，以及(C)交叉- 近端IXTH与远端CT吻合。再生纤维将是 用HRP标记，并映射它们的终端字段。功能研究 将在上述三项之后本地化响应的NST单元 通过定位c-fos蛋白表达来响应 电刺激第IXth神经和单细胞电刺激 NST的神经生理记录对味觉的反应， 触觉，以及舌头的热刺激。

Taste provides a model system for the study of regeneration because of the continual turnover of receptor cells and their trophic dependence on innervation by gustatory nerves. Studies on this project have shown that several cell-surface molecules are differentially expressed on taste cells and that this expression depends upon innervation by gustatory nerve fibers. The first Specific Aim is to determine the relationship between the expression of these molecules and taste cell type and whether this expression is determined by the innervating nerve or the gustatory epithelium. EM immunocytochemistry will address the relation between NCAM, L1, several blood group antigens, and other carbohydrates to taste cell type. The roles of the epithelium and the innervating nerve In determining the taste cell phenotype will be assessed by characterization of vallate and fungiform taste buds following cross-reinnervation of the posterior tongue by the chorda tympani (CT) nerve or the anterior tongue by the IXth nerve. The second Specific Aim is to determine the plasticity of central gustatory connections in the nucleus of the solitary tract (NST) following denervation and reinnervation of the taste buds. The first experiments will assess CNS responses to denervation. Preliminary studies show intense glial reactions in the NST following gustatory nerve injury as well as a significant constitutive expression of GAP-43 and astroglial and microglial markers in the NST. This suggests continual reorganization in the CNS accompanying normal taste cell turnover. The extent and time course of terminal degeneration and reactive gliosis following peripheral nerve injury will be studied by the cupric-silver degeneration method and antibodies against microglia (OX42) and astroglia (GFAP). Regeneration will be assessed using antibodies against regenerating axons (GAP43 and CDA-1). Golgi methods will be used to characterize the effects of taste nerve damage on NST cells. A second series of studies will examine the terminal field reorganization of regenerated IXth nerve axons following (a) IXth nerve crush, (b) IXth nerve crush combined with geniculate ganglion destruction, and (c) cross- anastomosis of proximal IXth to distal CT. Regenerated fibers will be labeled with HRP and their terminal fields mapped. Functional studies will localize responsive NST cells following the above three manipulations by mapping c-fos protein expression in response to electrical stimulation of the IXth nerve and by single-cell neurophysiological recording from the NST in response to gustatory, tactile, and thermal stimulation of the tongue.