Davis M, Sheard M H
Eur J Pharmacol. 1976 Feb;35(2):261-73. doi: 10.1016/0014-2999(76)90228-4.
In a series of 6 experiments the effects of p-chloroamphetamine (PCA) on the acoustic startle response in rats were investigated. 15 min after 5 mg/kg PCA startle amplitude was inhibited, 2-15 hr after PCA startle was facilitated. Rate of habituation however was not altered. Both the inhibitory and excitatory effects of PCA were blocked by pretreatment with p-chlorophenylalanine but not by alpha-methyl-p-tyrosine. 24 hr, 1 week and 4 weeks after PCA, initial startle amplitude was unchanged but PCA increased rate of sensitization over successive tone blocks. Increased sensitization was most pronounced at 10 mg/kg and absent at 2.5 mg/kg. The early inhibitory effect of PCA but not the later facilitatory effect was eliminated by reducing the level of background noise. The results suggest that inhibition of startle sensitization is associated with enhanced release of serotonin (5-HT) whereas enhancement of startle sensitization is associated with 5-HT depletion.
在一系列6个实验中，研究了对氯苯丙胺（PCA）对大鼠听觉惊吓反应的影响。给予5mg/kg PCA 15分钟后，惊吓幅度受到抑制，PCA给药后2 - 15小时，惊吓反应增强。然而，习惯化速率未改变。PCA的抑制和兴奋作用均被对氯苯丙氨酸预处理所阻断，但未被α-甲基对酪氨酸阻断。PCA给药后24小时、1周和4周，初始惊吓幅度未改变，但PCA增加了连续音块刺激下的敏感化速率。敏感化增强在10mg/kg时最为明显，在2.5mg/kg时不存在。降低背景噪声水平可消除PCA早期的抑制作用，但不能消除后期的促进作用。结果表明，惊吓敏感化的抑制与血清素（5-HT）释放增强有关，而惊吓敏感化的增强与5-HT耗竭有关。
