Frisch C, Hasenöhrl R U, Huston J P
Institute of Physiological Psychology and Center for Biological and Medical Research, Heinrich-Heine-University of Düsseldorf, Germany.
Neurosci Lett. 1997 Jun 27;229(2):89-92. doi: 10.1016/s0304-3940(97)00422-9.
The effect of the histamine H1-receptor antagonist chlorpheniramine on inhibitory avoidance conditioning was investigated in 31-month-old rats, using a one-trial step-through avoidance task. Immediately after the learning trial, old rats were injected intraperitoneally with 5 or 10 mg/kg d-chlorpheniramine. Control groups included vehicle-injected old and adult (4-month-old) rats and a group of aged animals given an injection of 10 mg/kg chlorpheniramine 5 h after the training trial. When tested 24 h after training, aged rats receiving 10 mg/kg chlorpheniramine exhibited longer step-through latencies than vehicle-treated old controls, indicative of superior learning of the task. The hypermnestic effects of 10 mg/kg chlorpheniramine were no longer evident when injection was performed 5 h, rather than immediately after the learning trial, ruling out enduring proactive effects of the treatment on test performance. Furthermore, vehicle-treated old rats showed poorer inhibitory avoidance performance than vehicle-treated adult controls. Thus, the improvement in performance after the 10 mg/kg dose of chlorpheniramine can be interpreted in terms of a compensation of performance deficits in the old rats.
使用单次通过式回避任务，研究了组胺H1受体拮抗剂氯苯那敏对31月龄大鼠抑制性回避条件反射的影响。学习试验后，立即给老年大鼠腹腔注射5或10mg/kg的右旋氯苯那敏。对照组包括注射溶媒的老年和成年（4月龄）大鼠，以及一组在训练试验后5小时注射10mg/kg氯苯那敏的老年动物。训练后24小时进行测试时，接受10mg/kg氯苯那敏的老年大鼠表现出比接受溶媒处理的老年对照组更长的通过潜伏期，表明对该任务有更好的学习效果。当在学习试验后5小时而非立即注射时，10mg/kg氯苯那敏的记忆增强作用不再明显，排除了该处理对测试表现的持久前摄效应。此外，接受溶媒处理的老年大鼠比接受溶媒处理的成年对照组表现出更差的抑制性回避表现。因此，10mg/kg剂量氯苯那敏给药后表现的改善可解释为对老年大鼠表现缺陷的补偿。
