CORTICAL MODULATION OF SOMATOSENSATION

描述(调查人员摘要)：在最近几年来自 申请者的这项资助侧重于氨基酸的免疫细胞化学。 在已识别的皮质下行通路的突触终末内 氨基酸神经递质池的更好的指示器 放射自显影或免疫细胞化学鉴定联合 在电子显微镜水平上的顺行追踪，从而允许 确定的人群中氨基酸密度的量化 突触末梢。首席调查员发现皮质醇 丘脑、背侧柱核和脊髓的终末 富含谷氨酸，尽管金颗粒的密度编码 这种氨基酸是可变的。一些航站楼也被浓缩了 天门冬氨酸，但颗粒密度之间相关性不大 在同一末端编码谷氨酸和天冬氨酸，意味着 分离皮质激素末端可以富含一种氨基酸，但不能 其他的。 从这项研究中可以明显看出，大脑皮层对 它通过谷氨酸能途径进行控制，即使它的作用 不同的皮质下结构的调制方式可能有所不同。不同的效果 可能是由不同的谷氨酸受体介导的 尤其是当它们的控制作用于一群兴奋性神经元的时候， 例如，在丘脑的腹基底部复合体(VB)中，而不是在 抑制性神经元，如丘脑两边的网状核 电路。 拟议研究的主要重点是探索这种可能性。这个 申请者将在以下位置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……里面 此外，申请人还将确定不同的共存 谷氨酸受体(AMPA、NMDA和代谢性)在同一皮层 VB和网状核内的突触及其局部分布 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.