Tiemann Laura, Heitmann Henrik, Schulz Enrico, Baumkötter Jochen, Ploner Markus
Department of Neurology, Technische Universität München, Munich, Germany; TUM-Neuroimaging Center, Technische Universität München, Munich, Germany.
Department of Pediatrics, Technische Universität München, Munich, Germany.
PLoS One. 2014 Apr 23;9(4):e96167. doi: 10.1371/journal.pone.0096167. eCollection 2014.
Pain is a multidimensional experience, which includes sensory, cognitive, and affective aspects. Converging lines of evidence indicate that dopaminergic neurotransmission plays an important role in human pain perception. However, the precise effects of dopamine on different aspects of pain perception remain to be elucidated. To address this question, we experimentally decreased dopaminergic neurotransmission in 22 healthy human subjects using Acute Phenylalanine and Tyrosine Depletion (APTD). During APTD and a control condition we applied brief painful laser stimuli to the hand, assessed different aspects of pain perception, and recorded electroencephalographic responses. APTD-induced decreases of cerebral dopaminergic activity did not influence sensory aspects of pain perception. In contrast, APTD yielded increases of pain unpleasantness. The increases of unpleasantness ratings positively correlated with effectiveness of APTD. Our finding of an influence of dopaminergic neurotransmission on affective but not sensory aspects of phasic pain suggests that analgesic effects of dopamine might be mediated by indirect effects on pain affect rather than by direct effects on ascending nociceptive signals. These findings contribute to our understanding of the complex relationship between dopamine and pain perception, which may play a role in various clinical pain states.
疼痛是一种多维度的体验，包括感觉、认知和情感方面。越来越多的证据表明，多巴胺能神经传递在人类疼痛感知中起着重要作用。然而，多巴胺对疼痛感知不同方面的确切影响仍有待阐明。为了解决这个问题，我们使用急性苯丙氨酸和酪氨酸耗竭法（APTD），对22名健康人类受试者的多巴胺能神经传递进行了实验性降低。在APTD期间和对照条件下，我们对手部施加短暂的疼痛激光刺激，评估疼痛感知的不同方面，并记录脑电图反应。APTD引起的脑多巴胺能活性降低并未影响疼痛感知的感觉方面。相反，APTD导致疼痛不适感增加。不适感评分的增加与APTD的效果呈正相关。我们发现多巴胺能神经传递对阶段性疼痛的情感而非感觉方面有影响，这表明多巴胺的镇痛作用可能是通过对疼痛情感的间接影响介导的，而不是通过对上行伤害性信号的直接影响。这些发现有助于我们理解多巴胺与疼痛感知之间的复杂关系，这可能在各种临床疼痛状态中发挥作用。
