CORTICAL MODULATION OF SOMATOSENSATION

描述（研究者摘要）：近年来， 申请人专注于氨基酸的免疫细胞化学 在确定的下行皮质通路的突触末端内， 更好的指示剂的神经递质库的氨基酸比 放射自显影或免疫细胞化学鉴定结合 电子显微镜水平的顺行追踪，从而允许 在一个鉴定的群体中的氨基酸密度的定量 突触末梢 主要研究者发现， 丘脑、背柱核和脊髓的终末为 富含谷氨酸盐，尽管金颗粒的密度编码 该氨基酸是可变的。 一些码头还增加了 天冬氨酸，但颗粒密度之间几乎没有相关性 在同一末端编码谷氨酸和天冬氨酸，这意味着 离皮质末端可能富含一种氨基酸，但离皮质末端不富含一种氨基酸。 其他. 从这项研究中可以明显看出，大脑皮层 其控制的方式amatergic途径，即使它的作用， 调制在不同的皮层下结构中可能不同。 不同的影响 皮层控制的不同可能由不同的谷氨酸受体介导 特别是当它们的控制作用于一群兴奋性神经元时， 例如在丘脑的腹基底复合体（VB）中， 抑制性神经元，例如网状核、丘脑的两个部分 电路. 这项研究的主要重点是探索这种可能性。 的 申请人将确定谷氨酸受体的亚基组成， VB和网状核内皮质丘脑纤维的终末。 在 此外，申请人还将确定不同的 谷氨酸受体（AMPA，NMDA和代谢型）在同一皮层 VB与网状核内突触及其分布 以及突触前和突触后的位置。

DESCRIPTION (Investigator's Abstract): During recent years of support from this grant the applicant has focused on immunocytochemistry for amino acids within synaptic terminals of identified descending cortical pathways as a better indicator of the neurotransmitter pool of an amino acid than the autoradiographic or immunocytochemical identification combined with anterograde tracing at the electron microscopic level, thus permitting quantification of the density of amino acids in an identified population of synaptic endings. The principal investigator found that corticofugal terminals in the thalamus, dorsal column nuclei and spinal cord were enriched with glutamate, though the density of gold particles coding for this amino acid was variable. Some terminals were also enriched with aspartate but little correlation existed between the density of particles coding for glutamate and for aspartate in the same terminal, implying that corticofugal terminals may be enriched with one amino acid but not the other. From this research it has become apparent that the cerebral cortex exerts its control by way of glutamatergic pathways even though the role of its modulation may vary in different subcortical structures. Different effects of cortical control may be mediated by different glutamate receptors especially where their control is exerted on a pool of excitatory neurons, e.g. in the ventrobasal complex (VB) of the thalamus versus a pool of inhibitory neurons, e.g. in the reticular nucleus, both parts of thalamic circuits. The main focus of the proposed research is to explore this possibility. The applicant will determine the subunit composition of glutamate receptors at the ending of corticothalamic fibers in VB and in the reticular nucleus. In addition, the applicant will also determine the co-existence of different glutamate receptors (AMPA, NMDA and metabotropic) at the same cortical synapse in VB and reticular nucleus, as well their topographic arrangement and presynaptic versus postsynaptic location.