Horing Bjoern, McCubbin James A, Moore Dewayne, Muth Eric R
Department of Psychology, Clemson University, Clemson, South Carolina, USA.
Psychophysiology. 2016 Oct;53(10):1600-7. doi: 10.1111/psyp.12724. Epub 2016 Jul 18.
Resting blood pressure (BP) shows a negative relationship with pain sensitivity (BP-related hypoalgesia). In chronic pain conditions, this relationship is inverted. The precise mechanisms responsible for the inversion are unknown. Using a tonic pain protocol, we report findings closely resembling this inversion in healthy participants. Resting BP and state measures of anxiety and mood were assessed from 33 participants (21 female). Participants then immersed their dominant hand in painfully hot water (47 °C) for five trials of 1-min duration, with 30-s intertrial intervals. Throughout the trials, participants continually registered their pain. After a 35-min intermission, the trial sequence was repeated. A disassociation of the negative relationship of resting systolic BP (as per Trial 1) was found using hierarchical linear modeling (p < .001, R(2) = .07). The disassociation unfolds over each consecutive trial, with an increasingly positive relationship. In Sequence 2, the initially negative relationship is almost completely absent. Furthermore, the association of BP and pain was found to be moderated by anxiety, such that only persons with low anxiety exhibited BP hypoalgesia. Our findings expand the existing literature by incorporating anxiety as a moderator of BP hypoalgesia. Furthermore, the protocol emulates the changing relationship between BP and pain observed in chronic pain patients. The protocol has potential as a model for chronic pain; however, future research should determine if similar physiological systems are involved. The finding holds potential diagnostic or prognostic relevance for certain clinical pain conditions, especially those involving dysfunction of the descending modulation of pain.
静息血压（BP）与疼痛敏感性呈负相关（血压相关的痛觉减退）。在慢性疼痛情况下，这种关系会反转。导致这种反转的确切机制尚不清楚。通过一项持续性疼痛方案，我们报告了在健康参与者中发现的与这种反转极为相似的结果。对33名参与者（21名女性）的静息血压以及焦虑和情绪的状态指标进行了评估。参与者随后将其优势手浸入47°C的热水中，进行5次每次持续1分钟的试验，每次试验间隔30秒。在整个试验过程中，参与者持续记录他们的疼痛程度。在35分钟的间歇期后，重复试验序列。使用分层线性模型发现静息收缩压的负相关关系（根据试验1）出现了分离（p <.001，R² =.07）。这种分离在每个连续试验中逐渐显现，呈现出越来越正的关系。在序列2中，最初的负相关关系几乎完全消失。此外，发现血压与疼痛之间的关联受焦虑调节，只有低焦虑的人表现出血压痛觉减退。我们的研究结果通过将焦虑作为血压痛觉减退的调节因素纳入其中，扩展了现有文献。此外，该方案模拟了慢性疼痛患者中观察到的血压与疼痛之间不断变化的关系。该方案有潜力成为慢性疼痛的模型；然而，未来的研究应确定是否涉及相似的生理系统。这一发现对于某些临床疼痛状况，特别是那些涉及疼痛下行调节功能障碍的状况，具有潜在的诊断或预后意义。
