Department of Psychology, Swarthmore College, Swarthmore, PA 19081, United States.
Pharmacol Biochem Behav. 2011 Jun;98(4):539-43. doi: 10.1016/j.pbb.2011.03.005. Epub 2011 Mar 17.
Previous work has shown that the effect of opioid-receptor blockade on memory modulation is critically dependent upon the intensity of stress. The current study determined the effect of adrenergic-receptor blockade on memory modulation under varied levels of stress and then compared the effect of adrenergic-receptor blockade under intense stress to that of a) opioid-receptor blockade and b) concurrent opioid- and adrenergic-receptor blockade. In the first experiment, the β-adrenergic-receptor blocker propranolol impaired retention in the passive-avoidance procedure when administered immediately after exposure to intense stress (passive-avoidance training followed by swim stress) but not mild stress (passive-avoidance training alone). In the second experiment, while separate administration of either propranolol or the opioid-receptor blocker naloxone immediately after exposure to intense stress impaired retention, the combined administration of propranolol and naloxone failed to do so. These findings demonstrate that the effect of β-adrenergic-receptor blockade or opioid-receptor blockade on memory modulation in the passive-avoidance procedure is dependent upon the intensity of stress, and suggest that concurrent inactivation of endogenous adrenergic- and opioid-based memory modulation systems under stressful conditions is protective of memory.
先前的研究表明，阿片受体阻断对记忆调节的影响取决于应激的强度。本研究在不同水平的应激下确定了肾上腺素能受体阻断对记忆调节的影响，然后比较了在强烈应激下肾上腺素能受体阻断的效果与以下两者的效果：a) 阿片受体阻断；b) 同时阻断阿片受体和肾上腺素能受体。在第一个实验中，β-肾上腺素能受体阻滞剂普萘洛尔在暴露于强烈应激后（被动回避训练后游泳应激）立即给药时会损害被动回避程序中的保留，但在轻度应激（单独进行被动回避训练）时不会。在第二个实验中，虽然在暴露于强烈应激后立即单独给予普萘洛尔或阿片受体阻滞剂纳洛酮都会损害保留，但联合给予普萘洛尔和纳洛酮则不会。这些发现表明，β-肾上腺素能受体阻断或阿片受体阻断对被动回避程序中记忆调节的影响取决于应激的强度，并表明在应激条件下同时失活内源性肾上腺素能和基于阿片类的记忆调节系统对记忆具有保护作用。
