Preclinical research has demonstrated that exposure to acute stress is associated with attenuated pain perception, so called stress-induced analgesia (SIA). Mechanisms of SIA in humans have not been reliably demonstrated. This study examined the role of the endogenous opioid system in the impact of combined interpersonal and mental stressors on evoked pain responses in 84 participants (34 women). Using a within-subject, double-blinded, counterbalanced design, participants were administered either oral placebo or the opioid antagonist naltrexone (50 mg) across two testing sessions. In each session, they experienced two evoked pain stimuli (cold pressor test [CPT], heat pain) after an extended rest period (rest condition) and after exposure to an acute stressor (a combination of public speaking and mental arithmetic challenge; stress condition). Results showed that both stress and opioid blockade produced significant changes in hormonal and cardiovascular measures, consistent with successful induction of acute stress. Stress was associated with attenuated pain perception (SIA) as indicated by significantly increased CPT tolerance. These effects were particularly pronounced in individuals experiencing the stress condition first. More importantly, SIA effects on CPT tolerance were abolished by opioid blockade. There were no significant SIA effects on heat pain responses. This study demonstrates that the endogenous opioid system may mediate effects of acute stress on pain perception, although this effect seems to be qualified by the type of evoked pain stimuli experienced.

临床前研究表明，暴露于急性压力与减轻疼痛感有关，即所谓的压力诱导镇痛 (SIA)。人类 SIA 的机制尚未得到可靠证实。这项研究检查了内源性阿片类药物系统在人际和精神压力因素对 84 名参与者（34 名女性）诱发的疼痛反应的影响中的作用。使用受试者内、双盲、平衡设计，参与者在两个测试阶段接受口服安慰剂或阿片拮抗剂纳曲酮（50 毫克）。在每次会议中，他们在长时间休息（休息条件）和暴露于急性压力源（公开演讲和心算挑战的组合；压力条件）。结果表明，压力和阿片类药物阻断都使激素和心血管指标发生了显着变化，与成功诱导急性压力一致。如显着增加的 CPT 耐受性所示，压力与减轻的痛觉 (SIA) 相关。这些影响在首先经历压力状况的个体中尤为明显。更重要的是，阿片类药物阻断消除了 SIA 对 CPT 耐受性的影响。SIA 对热痛反应没有显着影响。这项研究表明，内源性阿片类药物系统可能会介导急性压力对疼痛感知的影响，尽管这种影响似乎受到所经历的诱发疼痛刺激类型的限制。与成功诱导急性应激一致。如显着增加的 CPT 耐受性所示，压力与减轻的痛觉 (SIA) 相关。这些影响在首先经历压力状况的个体中尤为明显。更重要的是，阿片类药物阻断消除了 SIA 对 CPT 耐受性的影响。SIA 对热痛反应没有显着影响。这项研究表明，内源性阿片类药物系统可能介导急性压力对疼痛感知的影响，尽管这种影响似乎受到所经历的诱发疼痛刺激类型的限制。与成功诱导急性应激一致。如显着增加的 CPT 耐受性所示，压力与减轻的痛觉 (SIA) 相关。这些影响在首先经历压力状况的个体中尤为明显。更重要的是，阿片类药物阻断消除了 SIA 对 CPT 耐受性的影响。SIA 对热痛反应没有显着影响。这项研究表明，内源性阿片类药物系统可能介导急性压力对疼痛感知的影响，尽管这种影响似乎受到所经历的诱发疼痛刺激类型的限制。这些影响在首先经历压力状况的个体中尤为明显。更重要的是，阿片类药物阻断消除了 SIA 对 CPT 耐受性的影响。SIA 对热痛反应没有显着影响。这项研究表明，内源性阿片类药物系统可能介导急性压力对疼痛感知的影响，尽管这种影响似乎受到所经历的诱发疼痛刺激类型的限制。这些影响在首先经历压力状况的个体中尤为明显。更重要的是，阿片类药物阻断消除了 SIA 对 CPT 耐受性的影响。SIA 对热痛反应没有显着影响。这项研究表明，内源性阿片类药物系统可能介导急性压力对疼痛感知的影响，尽管这种影响似乎受到所经历的诱发疼痛刺激类型的限制。