Jänig W, Häbler H J
Physiologisches Institut, Christian-Albrechts-Universität, Kiel, Germany.
Schmerz. 2002 Dec;16(6):429-46. doi: 10.1007/s00482-002-0187-5.
Visceral pain is diffusely localized, referred to deep somatic tissues, skin and viscera, frequently not correlated with an actual trauma, commonly correlated with strong negative affective reactions and accompanied by strong protective autonomic and motor reactions. It is correlated with the excitation of spinal (thoraco-lumbar, sacral) visceral afferents and (with a few exceptions) not with the excitation of vagal afferents. Spinal visceral afferents are polymodal and can be excited by physical and chemical stimuli. All groups of visceral afferents can be sensitized (e.g.by inflammation). Normally silent (mechanically insensitive) visceral afferents are recruited by inflammation. Individual visceral afferent neurons project in laminae I and V of the dorsal horn over several segments, medio-lateral over the entire width of the dorsal horn and to the contralateral side. Their activity is synaptically transmitted, in these and deeper laminae, to viscero-somatic convergent neurons which receive additional afferent synaptic input from skin and deep somatic tissues of the corresponding dermatomes,myotomes and sclerotomes. The mechanism of sensitization of viscerosomatic convergent neurons (central sensitization) during sensitization of spinal visceral afferents is unclear.Viscero-somatic tract neurons project to lower and upper brain stem,hypothalamus and via the thalamus to various cortex areas. Visceral nociception and pain is presumably (together with other visceral sensations and homeostatic regulations of autonomic body functions) primarily represented in the insula in the context of interoception. The insula obtains its main peripheral afferent input from lamina I neurons via the Nucleus ventromedialis posterior of the thalamus. The transmission of visceral impulses in the spinal cord is modulated by the endogenous control systems in the brain stem which are in turn under the control of cortex and limbic system.
内脏痛定位弥散，可牵涉到深部躯体组织、皮肤和内脏，常与实际创伤无关，通常与强烈的负面情感反应相关，并伴有强烈的自主性保护反应和运动反应。它与脊髓（胸腰段、骶段）内脏传入神经的兴奋相关，（少数情况除外）与迷走神经传入神经的兴奋无关。脊髓内脏传入神经是多模式的，可被物理和化学刺激所兴奋。所有内脏传入神经组均可被致敏（如通过炎症）。炎症可使原本静息（对机械刺激不敏感）的内脏传入神经被激活。单个内脏传入神经元投射至背角的Ⅰ层和Ⅴ层，跨越多个节段，在背角的整个宽度上呈内外侧分布，并投射至对侧。它们的活动在这些及更深层中通过突触传递给内脏-躯体汇聚神经元，这些神经元还从相应皮节、肌节和骨节的皮肤和深部躯体组织接收额外的传入突触输入。脊髓内脏传入神经致敏期间内脏-躯体汇聚神经元致敏（中枢致敏）的机制尚不清楚。内脏-躯体束神经元投射至脑桥下部和上部、下丘脑，并通过丘脑投射至各个皮质区域。内脏伤害感受和疼痛大概（与其他内脏感觉和自主身体功能的稳态调节一起）主要在脑岛的内感受背景中体现。脑岛主要通过丘脑后内侧核从Ⅰ层神经元获得外周传入输入。脊髓中内脏冲动的传递受脑干内源性控制系统的调节，而该系统又受皮质和边缘系统的控制。
