Genaro Karina, Prado Wiliam A
Department of Anesthesiology, University of California, Irvine, CA, USA.
Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
Eur J Neurosci. 2021 Apr 28. doi: 10.1111/ejn.15255.
Descending pain modulation involves multiple encephalic sites and pathways that range from the cerebral cortex to the spinal cord. Behavioral studies conducted in the 1980s revealed that electrical stimulation of the pretectal area causes antinociception dissociation from aversive responses. Anatomical and physiological studies identified the anterior pretectal nucleus and its descending projections to several midbrain, pontine, and medullary structures. The anterior pretectal nucleus is morphologically divided into a dorsal part that contains a dense neuron population (pars compacta) and a ventral part that contains a dense fiber band network (pars reticulata). Connections of the two anterior pretectal nucleus parts are broad and include prominent projections to and from major encephalic systems associated with somatosensory processes. Since the first observation that acute or chronic noxious stimuli activate the anterior pretectal nucleus, it has been established that numerous mediators participate in this response through distinct pathways. Recent studies have confirmed that at least two pain inhibitory pathways are activated from the anterior pretectal nucleus. This review focuses on rodent anatomical, behavioral, molecular, and neurochemical data that have helped to identify mediators of the anterior pretectal nucleus and pathways related to its role in pain modulation.
下行性疼痛调制涉及多个脑区和从大脑皮层到脊髓的通路。20世纪80年代进行的行为学研究表明，对顶盖前区进行电刺激会导致痛觉缺失与厌恶反应分离。解剖学和生理学研究确定了顶盖前核及其向下投射至几个中脑、脑桥和延髓结构。顶盖前核在形态上分为背侧部分（包含密集的神经元群体，即致密部）和腹侧部分（包含密集的纤维带网络，即网状部）。顶盖前核这两个部分的连接广泛，包括与躯体感觉过程相关的主要脑系统之间的显著投射。自从首次观察到急性或慢性有害刺激会激活顶盖前核以来，已经确定许多介质通过不同途径参与这一反应。最近的研究证实，至少有两条疼痛抑制通路从顶盖前核被激活。本综述重点关注啮齿动物的解剖学、行为学、分子和神经化学数据，这些数据有助于确定顶盖前核的介质及其在疼痛调制中的作用相关通路。
