Knyihár Elizabeth, Csillik Bertalan
Szegedi Tudományegyetem, Szent-Györgyi Albert Orvos- es Gyógyszerésztudományi Központ, Neurológiai Klinika, Szeged.
Ideggyogy Sz. 2006 Mar 20;59(3-4):87-97.
Traditional concept holds that the pain unit consists of three neurons. The first of these, the primary nociceptive neuron, starts with the nociceptors and terminates in the dorsal spinal cord. The second one, called spinothalamic neuron, crosses over in front of the central canal and connects the dorsal horn with the thalamus. The third one, called thalamo-cortical neuron, terminates in the "pain centres" of the cerebral cortex. While this simplistic scheme is useful for didactic purposes, the actual situation is more complex. First, in the periphery it is only nociception that occurs, while pain is restricted to the levels of thalamus and the cortex. Second, pain results from interactions of excitation and inhibition, from divergence and convergence and from attention and distraction, in a diffuse and plastic system, characteristic for all levels of organization. This study describes the major cytochemical markers of primary nociceptive neurons followed by the presentation of recent data on the functional anatomy of nociception and pain, with special focus on the intrinsic antinociceptive system and the role of nitrogen oxide, opiate receptors, nociceptin and nocistatin. In addition to the classic intrinsic antinociceptive centres such as the periaqueductal gray matter and the raphe nuclei, roles of several recently discovered members of the antinociceptive system are discussed, such as the pretectal nucleus, the reticular formation, the nucleus accumbens, the nucleus tractus solitarii, the amygdala and the reticular thalamic nucleus, this latter being a coincidence detector and a centre for attention and distraction. The localisation of cortical centres involved in the generation of pain are presented based on the results of studies using imaging techniques, and the structural basis of corticospinal modulation is also outlined. Seven levels of nociception and pain are highlighted where pharmacological intervention may be successful, 1. the peripheral nociceptor, 2. the spinal ganglion, 3. the multisynaptic system of the dorsal horn, 4. the modulatory system of the brain stem, 5. the antinociceptive system, 6. the multisynaptic system of the thalamus, and 7. the cortical evaluating and localisation system that is also responsible for descending (inhibiting) control. The many levels of nociception and pain opens new ways both for pharmacological research and the general practitioner aiming to alleviate pain.
传统观念认为，痛觉单元由三个神经元组成。其中第一个是初级伤害感受神经元，始于伤害感受器，终止于脊髓背侧。第二个称为脊髓丘脑束神经元，在中央管前方交叉，将背角与丘脑相连。第三个称为丘脑皮质神经元，终止于大脑皮质的“疼痛中枢”。虽然这个简单的模式在教学上很有用，但实际情况更为复杂。首先，在周围组织中仅发生伤害感受，而疼痛则局限于丘脑和皮质水平。其次，疼痛是由兴奋与抑制、发散与汇聚以及注意力和分心等因素在一个弥漫且具有可塑性的系统中相互作用产生的，这是所有组织层次的特征。本研究描述了初级伤害感受神经元的主要细胞化学标志物，随后展示了关于伤害感受和疼痛功能解剖学的最新数据，特别关注内在抗痛系统以及一氧化氮、阿片受体、痛敏肽和痛抑素的作用。除了经典的内在抗痛中枢，如导水管周围灰质和中缝核，还讨论了抗痛系统中几个最近发现的成员的作用，如顶盖前核、网状结构、伏隔核、孤束核、杏仁核和丘脑网状核，后者是一个巧合探测器以及注意力和分心的中枢。基于使用成像技术的研究结果，展示了参与疼痛产生的皮质中枢的定位，同时也概述了皮质脊髓调制的结构基础。强调了七个可能成功进行药物干预的伤害感受和疼痛水平，1. 外周伤害感受器，2. 脊髓神经节，3. 背角的多突触系统，4. 脑干的调制系统，5. 抗痛系统，6. 丘脑的多突触系统，7. 也负责下行（抑制）控制的皮质评估和定位系统。伤害感受和疼痛的多个层次为旨在减轻疼痛的药物研究和全科医生开辟了新途径。
