Hyson R L, Ashcraft L J, Drugan R C, Grau J W, Maier S F
Pharmacol Biochem Behav. 1982 Nov;17(5):1019-25. doi: 10.1016/0091-3057(82)90488-9.
Opioid and nonopioid mediated changes in pain sensitivity have been observed after exposure to various stressful conditions. A series of inescapable shocks sequentially produces an early form of analgesia which is not affected by the opiate antagonist, naltrexone, and a late antinociceptive response which is sensitive to reversal by naltrexone. Here, this is shown to be true over a wide range of doses. In a further experiment subjects given either escapable or inescapable shock were analgesic immediately after the stress session. However, the analgesia of inescapably shocked subjects was more sensitive to reversal by naltrexone. A final experiment revealed that inescapably shocked subjects, but not escapably shocked subjects, were hyperreactive to the analgesic effects of morphine 24 hr after shock. These results suggest that activation of an opiate system occurs only after extended exposure to stress and that this activation is greater when the stress is inescapable. Implications for opioid versus nonopioid mechanisms of stress-induced analgesia are discussed.
在暴露于各种应激条件后，已观察到阿片类和非阿片类药物介导的疼痛敏感性变化。一系列不可逃避的电击会依次产生一种不受阿片类拮抗剂纳曲酮影响的早期镇痛形式，以及一种对纳曲酮逆转敏感的晚期抗伤害感受反应。在此，这在很宽的剂量范围内都得到了证实。在另一项实验中，接受可逃避或不可逃避电击的受试者在应激期后立即出现镇痛作用。然而，不可逃避电击的受试者的镇痛作用对纳曲酮逆转更为敏感。最后一项实验表明，不可逃避电击的受试者在电击后24小时对吗啡的镇痛作用反应过度，而可逃避电击的受试者则没有。这些结果表明，阿片系统仅在长期暴露于应激后才被激活，并且当应激不可逃避时，这种激活作用更强。文中讨论了应激诱导镇痛的阿片类与非阿片类机制的意义。
