DESCENDING CONTROL OF SOMATOSENSORY INPUT

本研究从中枢调制的几个方面进行探讨 躯体感觉的 主要目标之一是确定 皮质神经元的神经递质在下降的起源 到躯体感觉丘脑、背柱核和 大鼠脊髓。 现有的证据表明，谷氨酸可能是 我们将采用免疫细胞化学的方法 结合染料的逆行运输来验证这一点。 免疫细胞化学双标法也将被用来研究 一些已知存在于非锥体皮质中的肽 神经元与谷氨酰胺能神经元共定位于VI层。 我们还希望研究是否调制VB活动的猫， 皮层和其他皮层下中心（例如，中缝核、导水管周围核、中脑核、中央核）。 灰色等）主要是通过直接接触内在GABA介导的， 能神经元 谷氨酸免疫细胞化学联合法 脱羧酶（GAD）和顺行追踪技术将在 电子显微镜水平。 计划中的这部分研究将 阐明可能涉及某些基本丘脑功能的机制 并将建立一个坚实的基础，进一步了解如何输入从 VB神经元的活动可能受到不同中枢的影响。 作为第三个主要目标，我们将试图回答是否GAD阳性神经元在 猫的VB含有被认为与某种形式的 控制神经传递。 这部分研究的基本原理 主要在于证明GABA能神经元，例如在 皮质，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 其他标志物可能反映了 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.