Salinas J A, Introini-Collison I B, Dalmaz C, McGaugh J L
Department of Psychology, University of Virginia, Charlottesville 22903, USA.
Neurobiol Learn Mem. 1997 Jul;68(1):51-9. doi: 10.1006/nlme.1997.3776.
These experiments examined the effects of posttraining intraamygdala administration of the muscarinic agonist, oxotremorine, and the beta-noradrenergic antagonist, propranolol, on memory for reduction in reward magnitude. Male Sprague-Dawley rats (175-200 g) implanted with bilateral intraamygdala cannulae were food deprived (maintained at 80% of body weight) and trained to run a straight alley (six trials/day) for either ten 45-mg food pellets (high reward) or one 45-mg food pellet (low reward) for 10 days. In Experiment One, the animals in the high-reward group were than shifted to a one-pellet reward and immediately given intraamygdala infusions (0.5 microliter/side) of either oxotremorine (10 ng) or phosphate buffer. Shifted training continued for 4 more days and no further injections were given. Shifted animals given the buffer solution displayed an increase in runway latencies but returned to preshift latencies by the fifth day of shifted training. In contrast, animals given oxotremorine exhibited increased latencies through the fifth day. In Experiment Two, rats were trained as in Experiment. One but immediately following the shift received intraamygdala infusions of oxotremorine (10 ng), propranolol (0.3 microgram), both, or phosphate buffer. Shifted vehicle-injected rats returned to preshift performance by the fifth day of shifted training. Shifted propranolol rats returned to preshift latencies by the third day of shifted training. In contrast, the shifted oxotremorine and the shifted oxotremorine/propranolol rats displayed longer latencies than unshifted controls through 5 days of shifted training. The findings indicate that the muscarinic cholinergic and beta-noradrenergic systems within the amygdala interact in regulating memory and support the view that noradrenergic influences are mediated through cholinergic activation.
这些实验研究了训练后向杏仁核内注射毒蕈碱激动剂氧化震颤素和β-去甲肾上腺素能拮抗剂普萘洛尔对奖励幅度降低记忆的影响。将植入双侧杏仁核套管的雄性斯普拉格-道利大鼠（175 - 200克）进行食物剥夺（维持在体重的80%），并训练其在直道上奔跑（每天6次试验），持续10天，以获取十颗45毫克的食物颗粒（高奖励）或一颗45毫克的食物颗粒（低奖励）。在实验一中，高奖励组的动物随后被改为单颗粒奖励，并立即向杏仁核内注射（每侧0.5微升）氧化震颤素（10纳克）或磷酸盐缓冲液。转换训练持续4天，不再进行进一步注射。注射缓冲液的转换动物在跑道潜伏期有所增加，但在转换训练的第五天恢复到转换前的潜伏期。相比之下，注射氧化震颤素的动物在第五天潜伏期持续增加。在实验二中，大鼠的训练方式与实验一相同，但在转换后立即向杏仁核内注射氧化震颤素（10纳克）、普萘洛尔（0.3微克）、两者或磷酸盐缓冲液。注射载体的转换大鼠在转换训练的第五天恢复到转换前的表现。注射普萘洛尔的转换大鼠在转换训练的第三天恢复到转换前的潜伏期。相比之下，转换后的氧化震颤素组和氧化震颤素/普萘洛尔组大鼠在转换训练的五天内潜伏期比未转换的对照组更长。研究结果表明，杏仁核内的毒蕈碱胆碱能系统和β-去甲肾上腺素能系统在调节记忆方面相互作用，并支持去甲肾上腺素能影响是通过胆碱能激活介导的这一观点。
