CONTROL OF OLFACTORY AND GUSTATORY NEURON REGENERATION

本提案中所述研究的广泛目标是了解 (i)发育和再生的化学感受神经如何 （二）如何实现目标;（三）如何实现目标。 他们停止生长，（iii）他们如何改变他们的基因表达， 增长模式向成熟模式转变，在成熟模式中，它们形成功能关系 和目标在一起 我们认为在味觉和嗅觉系统中 神经生长的环境和目标 结构提供了调节生长和成熟行为的信号 神经。 这些信号可能包括导航引导线索， “停止生长”信号和诱导基因表达变化的信号。 在大鼠舌中，2条感觉神经，即舌固有（LP）分支， 三叉神经和鼓索（CT）提供神经支配， 乳突 在发育过程中，它们同时进入舌头， 针对不同的目标。 CT支配的顶点的 菌状乳头，而LP支配这些菌状乳头的其他区域。 以及舌头的其他部分。 我们建议 识别将这些神经引导到不同位置的导航信号， 菌状乳头中的靶点;（1）绘制 细胞外基质（ECM）分子可能促进（或抑制）神经 生长;（2）鉴定生长和再生的表面分子 舌头上的感觉神经可能作为信号的受体 在环境中或在突触目标上;（3）识别阳性和 轴突生长的负向信号和停止信号 （4）识别改变基因表达的信号， 味觉神经元 含有轮廓乳头的味蕾是 由舌咽神经支配。 因为味觉和 舌咽神经中的躯体感觉神经来自两个不同的 我们也将能够检查其中一些问题， 轮廓乳头的神经支配。 在嗅觉系统中， 建议（1）识别嗅觉轴突的“停止生长”信号;（2） 识别可溶性或膜相关的延髓信号， 嗅觉神经元的基因表达。 体内和体外方法 将用于

The broad goal of the research described in this proposal is to understand (i) how developing and regenerating chemosensory nerves navigate their paths to their appropriate targets; (ii) how, when they reach the targets, they stop growing and (iii) how they alter their gene expression from a growth mode to a mature mode in which they form a functional relationship with the target. In both the taste and the olfactory systems we suggest that both the environment through which the nerve growth and the target structures provide signals that regulate the behavior of growing and mature nerve. These signals are likely to include navigational guidance cues, "stop growth" signals, and signals that induce changes in gene expression. In the rat tongue, 2 sensory nerves, the lingual proper (LP) branch of the trigeminal, and the chorda tympani (CT) provide innervation to fungiform papillae. During development they enter the tongue simultaneously but are directed to different targets. The CT innervates the apices of the fungiform papillae whereas the LP innervates other regions of these structures, as well as the remainder of the anterior tongue. We propose to identify the navigational signals directing these nerves to different targets in the fungiform papilla by; (1) mapping the distribution of extracellular matrix (ECM) molecules that might promote (or inhibit) nerve growth; (2) identifying surface molecules on growing and regenerating sensory nerves in the tongue that might act as receptors of signals present in the environment or on the synaptic target; (3) identifying positive and negative tropic signals and stop signals for axonal growth in the developing tongue; (4) identifying signals that alter gene expression in gustatory neurons. The taste bud containing circumvallate papilla is innervated by the glossopharyngeal nerve. Because gustatory and somatosensory nerves in the glossopharyngeal nerve arise from two distinct ganglia in the rat we will also be able to examine some of these issues in the innervation o the circumvallate papilla. In the olfactory system we propose (1) to identify the "stop growth" signal for olfactory axons; (2) to identify soluble or membrane-associated bulbar signals that act to alter gene expression in olfactory neurons. Both in vivo and in vitro methods will be used.