Sandstrom N J, Arnold H M, Williams C L
Department of Psychology: Experimental, Duke University, Durham, North Carolina 27708-0086, USA.
Behav Neurosci. 1998 Aug;112(4):909-19. doi: 10.1037//0735-7044.112.4.909.
The authors report that the expression of a conditioned odor aversion is impaired in preweanling rats when they are conditioned on Postnatal Day 12 and tested under the influence of scopolamine hydrobromide (0.2 or 0.5 mg/kg, intraperitoneal) after a 48-hr, but not after a 2-hr, retention interval (Experiment 1). This effect of scopolamine is not dependent on maturation of the cholinergic system between Days 12 and 14 (Experiment 2), nor is it due to peripheral mechanisms (Experiment 3). When pups are reexposed to the unconditioned stimulus (footshock) before drug administration, performance on the 48-hr retention test is not impaired by scopolamine (Experiment 4). These findings demonstrate that the cholinergic system may be critical for the retrieval and expression of long-term or weak memories in young rats. However, the expression of active memories (recent or recently reactivated) may not be dependent on the cholinergic system to the same extent as is the expression of inactive memories.
作者报告称，在出生后第12天对断奶前大鼠进行条件化训练，并在48小时（而非2小时）的保留间隔后，在氢溴酸东莨菪碱（0.2或0.5毫克/千克，腹腔注射）影响下进行测试时，条件性气味厌恶的表达受损（实验1）。东莨菪碱的这种作用不依赖于第12天至14天胆碱能系统的成熟（实验2），也不是由外周机制导致的（实验3）。当幼崽在给药前再次暴露于非条件刺激（足部电击）时，东莨菪碱不会损害48小时保留测试的表现（实验4）。这些发现表明，胆碱能系统可能对幼鼠长期或微弱记忆的提取和表达至关重要。然而，活跃记忆（近期或最近重新激活的记忆）的表达可能不像非活跃记忆的表达那样在同等程度上依赖于胆碱能系统。
