Broman J
Department of Cell Biology, Faculty of Health Sciences, University of Linköping, Sweden.
Anat Embryol (Berl). 1994 Mar;189(3):181-214. doi: 10.1007/BF00239008.
Investigations during recent years indicate that many different neuroactive substances are involved in the transmission and modulation of somesthetic information in the central nervous system. This review surveys recent developments within the field of somatosensory neurotransmission, emphasizing immunocytochemical findings. Increasing evidence indicates a widespread role for glutamate as a fast-acting excitatory neurotransmitter at different levels in somatosensory pathways. Several studies have substantiated a role for glutamate as a neurotransmitter in primary afferent neurons and in corticofugal projections, and also indicate a neurotransmitter role for glutamate in ascending somatosensory pathways. Other substances likely to be involved in somatosensory neurotransmission include the neuropeptides. Many different peptides have been detected in primary afferent neurons with unmyelinated or thinly myelinated axons, and are thus likely to be directly involved in primary afferent neurotransmission. Some neurons giving rise to ascending somatosensory pathways, primarily those with cell bodies in the dorsal horn, are also immunoreactive for peptides. Recent investigations have shown that the expression of neuropeptides, both in primary afferent and ascending tract neurons, may change as a result of various kinds of peripheral manipulation. The occurrence of neurotransmitters in intrinsic neurons and neurons providing modulating inputs to somatosensory relay nuclei (the dorsal horn, the lateral cervical nucleus, the dorsal column nuclei and the ventrobasal thalamus) is also reviewed. Neurotransmitters and modulators in such neurons include acetylcholine, monoamines, GABA, glycine, glutamate, and various neuropeptides.
近年来的研究表明，许多不同的神经活性物质参与中枢神经系统中躯体感觉信息的传递和调制。本综述概述了躯体感觉神经传递领域的最新进展，重点强调免疫细胞化学研究结果。越来越多的证据表明，谷氨酸作为一种快速起效的兴奋性神经递质，在躯体感觉通路的不同水平发挥着广泛作用。多项研究证实了谷氨酸在初级传入神经元和皮质传出投射中作为神经递质的作用，同时也表明谷氨酸在躯体感觉上行通路中具有神经递质功能。其他可能参与躯体感觉神经传递的物质包括神经肽。在具有无髓鞘或薄髓鞘轴突的初级传入神经元中已检测到许多不同的肽，因此它们可能直接参与初级传入神经传递。一些发出躯体感觉上行通路的神经元，主要是那些胞体位于背角的神经元，也对肽有免疫反应。最近的研究表明，由于各种外周操作，初级传入神经元和上行传导束神经元中神经肽的表达可能会发生变化。本文还综述了内在神经元以及向躯体感觉中继核（背角、外侧颈核、薄束核和腹后丘脑）提供调制性输入的神经元中神经递质的存在情况。这些神经元中的神经递质和调制物包括乙酰胆碱、单胺、γ-氨基丁酸、甘氨酸、谷氨酸以及各种神经肽。
