Trimble Edward A, Kell Parker A, Avella Matteo A, France Christopher R, Rhudy Jamie L
Department of Biochemistry, The University of Tulsa, Tulsa, OK, USA.
Department of Psychology, The University of Tulsa, Tulsa, OK, USA.
J Pain Res. 2024 Feb 1;17:489-500. doi: 10.2147/JPR.S442431. eCollection 2024.
The A118G polymorphism in the opioid receptor mu 1 gene (OPRM1) is associated with decreased opioid receptor availability, altered emotion, and increased pain. Given that emotions modulate pain (positive emotions inhibit pain, negative emotions enhance pain), we predicted that G allele carriers would experience impaired emotional modulation of pain compared to non-G allele carriers.
Emotional pictures (ie, erotica, neutral, attack) from the International Affective Picture System were used by permission from the authors to experimentally manipulate emotions in 64 adult participants while painful electrocutaneous stimulations were delivered in a cross-sectional study. Ratings of arousal and valence/pleasure were made in response to pictures, and pain ratings and a physiological measure of spinal nociception (ie, nociceptive flexion reflex, NFR) were collected in response to painful stimulations. Secondary analyses were conducted to examine the relationship between the A118G polymorphism and emotional modulation of pain/NFR.
Exposure to emotional pictures elicited similar changes in valence, but G-carriers rated erotic pictures as more arousing. In non-carriers, pain was facilitated by attack pictures and pain and NFR were inhibited by erotic pictures relative to neutral pictures. Among G-carriers, pain was facilitated by negative emotional pictures but there was no pain or NFR inhibition by positive emotional pictures.
The altered response to pleasant stimuli further supports the role of opioids in appetitive behavior and describes how the A118G polymorphism may prevent carriers from inhibiting pain during pleasure.
阿片受体μ1基因（OPRM1）中的A118G多态性与阿片受体可用性降低、情绪改变及疼痛加剧有关。鉴于情绪可调节疼痛（积极情绪抑制疼痛，消极情绪增强疼痛），我们预测与非G等位基因携带者相比，G等位基因携带者在疼痛的情绪调节方面会受损。
经作者许可，使用国际情感图片系统中的情感图片（即色情、中性、攻击性图片）对64名成年参与者的情绪进行实验性操控，同时在一项横断面研究中施加疼痛性皮肤电刺激。针对图片进行唤醒度和效价/愉悦度评分，并针对疼痛刺激收集疼痛评分以及脊髓伤害感受的生理指标（即伤害性屈曲反射，NFR）。进行了二次分析以检验A118G多态性与疼痛/NFR的情绪调节之间的关系。
接触情感图片引发了类似的效价变化，但G等位基因携带者将色情图片评为更具刺激性。在非携带者中，相对于中性图片，攻击性图片会加剧疼痛，而色情图片则会抑制疼痛和NFR。在G等位基因携带者中，负面情感图片会加剧疼痛，但正面情感图片不会抑制疼痛或NFR。
对愉悦刺激的反应改变进一步支持了阿片类药物在动机性行为中的作用，并描述了A118G多态性可能如何阻止携带者在愉悦过程中抑制疼痛。
