Izquierdo I, Netto C A
Centro de Memoria, U.F.R.G.S., Porto Alegre, RS, Brazil.
Behav Neural Biol. 1990 Jan;53(1):140-6. doi: 10.1016/0163-1047(90)90933-w.
Naloxone administered at a dose of 0.2 mg/kg post-training antagonizes the deleterious effect of post-training beta-endorphin administration and prevents the enhancing effect of pretest beta-endorphin administration, on retention of a step-down inhibitory avoidance task in rats. Given at a higher dose (0.4 mg/kg), naloxone caused, in addition to these effects, a pronounced retrograde facilitation which was additive with that caused by post-training ACTH or epinephrine administration. These findings show that post-training naloxone has two different effects or sets of effects, each with a different dose threshold: An interference with beta-endorphin induced state dependency and a true modulatory effect.
训练后以0.2毫克/千克的剂量给予纳洛酮，可拮抗训练后给予β-内啡肽的有害作用，并防止测试前给予β-内啡肽对大鼠一步跳下抑制性回避任务记忆保持的增强作用。以更高剂量（0.4毫克/千克）给予纳洛酮时，除了这些作用外，还会产生明显的逆行促进作用，这与训练后给予促肾上腺皮质激素或肾上腺素所产生的作用相加。这些发现表明，训练后给予纳洛酮有两种不同的作用或作用组，每种都有不同的剂量阈值：干扰β-内啡肽诱导的状态依赖性和真正的调节作用。
