Muscarinic regulation of plasticity in the brain

描述(由申请者提供)：这个项目旨在阐明将经验转化为大脑结构变化的机制，使成年动物能够提高它们的行为表现。我们的模型系统，觅食诱导蜜蜂肌肉小体的生长(昆虫大脑学习和记忆中心)，允许在行为、细胞和分子水平上进行研究。我们的建议是基于一个令人惊讶但强有力的证明，即用毒扁豆碱激动剂匹罗卡品治疗笼中蜜蜂，产生的大脑可塑性与一周的真实觅食体验所产生的结果相同。我们将：1.使用一种新的经验替换技术来确定通过胆碱能通路的信号如何与觅食诱导的蘑菇体神经纤维体积的增加有关；2.使用高尔基体技术来确定匹罗卡品引起的蘑菇体神经元(Kenyon细胞)变化的细胞表型；以及3.使用全蜜蜂基因组微阵列来鉴定通过毒扁豆碱途径对信号做出反应的在蘑菇体中表达的基因，然后用定量RT-PCR和原位杂交来证实和扩展这些结果。蜜蜂为这些研究提供了一个极好的模型系统，因为现在已经有了适当的工具，比如测序的基因组，而且有可能在神经解剖学和分子水平上严格操纵蜜蜂在自然条件下的经验和研究效果。这项研究的主要意义在于，它将揭示体验如何与大脑的可塑性相关联。在整个动物界，神经系统功能在分子水平上的广泛保守使我们对昆虫的研究结果广泛应用于行为发育领域。这项研究与公众健康有关，因为使用更简单的昆虫神经系统可以有效地进行实验，很可能揭示学习如何改变包括人类在内的所有动物的大脑。这样的理解是开发治疗方法的第一步，以改善大脑损伤后的人类学习。我们的结果还将为开发治疗伴随人类衰老而来的智力功能下降的方法提供方向。

DESCRIPTION (provided by applicant): This project is designed to elucidate mechanisms that translate experience into changes in brain structure that allow adult animals to enhance their behavioral performance. Our model system, foraging-induced growth of the mushoom bodies (insect brain center for learning and memory) in the honey bee, permits investigations at the behavioral, cellular, and molecular levels. Our proposal is based on the surprising, but robust, demonstration that treatment of caged bees with a muscarinic agonist, pilocarpine, results in brain plasticity identical to that produced by a week of real foraging experience. We will: 1. determine how signaling via cholinergic pathways is related to foraging-induced increases in the volume of mushroom body neuropil using a novel experience-replacement technique; 2. determine the cellular phenotype of pilocarpine-induced changes in mushroom body neurons (Kenyon cells) using the Golgi technique; and 3. identify genes expressed in the mushroom bodies responsive to signaling via muscarinic pathways using whole bee genome microarrays, and then confirm and extend these results with quantitative RT-PCR and in situ hybridization. The bee provides a superb model system for these studies because appropriate tools, such as a sequenced genome, are now available, and because it is possible to rigorously manipulate the experience of the bee under naturalistic conditions and study effects at the neuroanatomical and molecular levels. The principal significance of this research is that it will reveal how experience is coupled to brain plasticity. Extensive conservation of nervous system function at the molecular level across the animal kingdom makes the results of our investigations on an insect broadly applicable within the field of behavioral development. This research is relevant to public health because experiments that can be efficiently performed using the simpler insect nervous system are likely to reveal how learning changes the brain in all animals, including humans. Such understanding is the first step in the development of therapies to improve human learning after brain damage. Our results will also suggest directions for the development of treatments for the decline in mental function that accompanies human aging.