DESCENDING CONTROL OF SOMATOSENSORY INPUT

拟议的研究涉及中央调制的几个方面 体感的感觉。主要目标之一是确定 降支起始处皮质神经元的神经递质 丘脑躯体感觉核、背侧柱核和 大鼠脊髓。现有证据表明，谷氨酸可能是 涉及到这些神经元，我们将使用免疫细胞化学方法 结合染料的逆行运输来验证这一点。 双标记免疫细胞化学也将被用来研究 一些已知存在于非锥体皮质的多肽 神经元与谷氨酸能神经元共定位于第VI层。 我们还希望研究在猫的VB活动的调节是否 皮质和其他皮质下中枢(如中缝核、中脑导水管周围 Gray等)主要通过直接接触内在的GABA- 能神经元。抗谷氨酸免疫细胞化学的联合应用 脱羧酶(GAD)和顺行追踪技术将在 电子显微镜水平。这部分计划的研究将 阐明一些可能涉及丘脑基本功能的机制 并将为进一步深入了解来自 不同中枢可能影响VB神经元的活动。 作为第三个主要目标，我们将尝试回答GAD阳性神经元在 猫的Vb含有多肽，据信与某种形式的 神经传递的控制。这部分研究的基本原理 主要在于证明了GABA能神经元，例如在 大脑皮层，也可能表达其他分子标记。此外，物种 GABA能神经元的存在差异和共同定位 其他标记可能反映了日益细化和复杂的 丘脑核团的功能特征。

The proposed research deals with several aspects of the central modulation of somatosensation. One of the main goals is to identify the neurotransmitter of cortical neurons at the origin of the descending pathways to the somatosensory thalamus, the dorsal column nuclei and the spinal cord in rats. Available evidence suggests that glutamate may be involved in these neurons and we will employ an immunocytochemical approach combined with the retrograde transport of dyes to verify this. Double-labeling immunocytochemistry will be also employed to investigate whether some of the peptides known to be present in non-pyramidal cortical neurons co-localize with glutamergic neurons in layer VI. We also wish to investigate whether modulation of VB activity in cats by the cortex and other subcortical centers (e.g. raphe nuclei, periaqueductal gray, etc.) is primarily mediated via direct contacts upon intrinsic GABA - ergic neurons. Combination of immunocytochemistry against glutamic acid decarboxylase (GAD) and anterograde tracing techniques will be employed at the electron microscopical level. This part of the planned research will elucidate mechanisms presumably involved in some basic thalamic functions and will establish a solid basis for further insights in how input from different centers may affect the activity of VB neurons. As a third main goal, we'll try to answer whether GAD positive neurons in cat's VB contain peptides that are believed to be involved in some form of control of neurotransmission. The rationale for this part of the research lies mainly in the demonstration that GABA - ergic neurons, e.g. in the cortex, may express other molecular markers. Furthermore species differences in the presence of GABA - ergic neurons and co-localisation of other markers may reflect increasing elaboration and complexity of functional features of thalamic nuclei.