Cruz-Morales S E, Duran-Arevalo M, Diaz Del Guante M A, Quirarte G, Prado-Alcala R A
Behavioral Pharmacology, Enep-Iztacala, National University of Mexico; Mexico, D.F.
Behav Neural Biol. 1992 May;57(3):256-9. doi: 10.1016/0163-1047(92)90248-3.
Acetylcholine-receptor blockers produce amnesia of aversively motivated behaviors. However, when animals are submitted to relatively high intensities of footshock (over-reinforcement), anticholinergic treatment does not induce memory impairments. The aim of this work was to determine whether the antiamnesic effect produced by increasing the magnitude of the negative reinforcer is gradually established or if a threshold should be reached to obtain such an effect. Wistar rats were trained in passive avoidance using 2.5, 2.6, 2.7, 2.8, 2.9 or 3.0 mA; 5 min after training they were given one systemic injection of scopolamine (8 mg/kg). An amnesic state was produced in the groups that were trained with the lower intensities (2.5-2.7 mA); with the three higher intensities near-perfect retention was evident. These results suggest that acetylcholine is critically involved in memory consolidation, and that by increasing the magnitude of the negative reinforcer, a threshold is reached where cholinergic activity of the nervous system is not necessary for the development of the consolidation process.
乙酰胆碱受体阻滞剂会导致厌恶性动机行为的失忆。然而，当动物接受相对高强度的足部电击（过度强化）时，抗胆碱能治疗不会引起记忆障碍。这项研究的目的是确定通过增加负性强化物的强度产生的抗失忆效应是逐渐形成的，还是需要达到一个阈值才能获得这种效应。将Wistar大鼠分别用2.5、2.6、2.7、2.8、2.9或3.0毫安进行被动回避训练；训练5分钟后，给它们一次性全身注射东莨菪碱（8毫克/千克）。用较低强度（2.5 - 2.7毫安）训练的组产生了失忆状态；而用较高的三种强度训练的组则表现出近乎完美的记忆保持。这些结果表明，乙酰胆碱在记忆巩固中起关键作用，并且通过增加负性强化物的强度，会达到一个阈值，此时神经系统的胆碱能活动对于巩固过程的发展不再必要。
