Frew Ashley K, Drummond Peter D
School of Psychology, Murdoch University, Perth, WA, Australia.
Pain. 2007 Nov;132 Suppl 1:S77-S85. doi: 10.1016/j.pain.2007.04.010. Epub 2007 May 18.
Opioid neurotransmission modulates pain and negative affect during psychological stress. To determine whether these effects differ between men and women, the opioid receptor antagonist naltrexone or placebo was administered double-blind to 21 men and 22 women before they completed 30 min of difficult mental arithmetic. To heighten negative affect, participants received seven moderately noxious electric shocks during the math task, which were believed to be contingent upon performance. Before and after the math task, participants rated pain intensity and unpleasantness while their left hand was immersed in 2 degrees C water for up to 4 min. Anxiety, discouragement and anger were also rated before, during and after the math task. Tolerance of cold-induced pain was greater in men, whereas discouragement during the math task was greater in women. Opioid blockade did not influence ratings of negative affect, which increased in line with the intensity and unpleasantness of shock-induced pain. The intensity and unpleasantness of cold-induced pain increased after the math task only in women administered naltrexone. Within the naltrexone condition, pain ratings increased most in the most discouraged subjects. However, this relationship was absent in placebo recipients, implying that the hyperalgesic effect of psychological distress was tempered by opioid release. Greater stress-evoked discouragement in women than men may explain why cold-induced pain increased after the math task only in women administered naltrexone.
阿片类神经传递在心理应激过程中调节疼痛和负面情绪。为了确定这些效应在男性和女性之间是否存在差异，在21名男性和22名女性完成30分钟的复杂心算之前，对他们双盲给予阿片受体拮抗剂纳曲酮或安慰剂。为了增强负面情绪，参与者在数学任务期间接受了七次中度有害的电击，这些电击被认为取决于表现。在心算任务前后，当参与者的左手浸入2摄氏度的水中长达4分钟时，他们对疼痛强度和不愉快程度进行评分。在数学任务之前、期间和之后，还对焦虑、气馁和愤怒进行了评分。男性对冷诱导疼痛的耐受性更高，而女性在数学任务期间的气馁程度更高。阿片类药物阻断对负面情绪评分没有影响，负面情绪评分随着电击诱导疼痛的强度和不愉快程度而增加。仅在接受纳曲酮治疗的女性中，冷诱导疼痛的强度和不愉快程度在心算任务后增加。在纳曲酮治疗组中，最气馁的受试者疼痛评分增加最多。然而，在接受安慰剂的受试者中不存在这种关系，这意味着心理应激的痛觉过敏效应被阿片类药物释放所缓和。女性比男性在应激时更易产生气馁情绪，这可能解释了为什么仅在接受纳曲酮治疗的女性中，冷诱导疼痛在心算任务后会增加。
