Ogren S O, Berge O G, Johansson C
Psychopharmacology (Berl). 1985;87(3):260-5. doi: 10.1007/BF00432704.
The effects of selective lesions of the descending serotonergic (5-HT) pathways on analgesia and avoidance deficit induced by the 5-HT releasing compound p-chloroamphetamine (PCA, 2.5 mg/kg) were investigated in male rats. Intrathecal injection of 5,6-DHT (20 micrograms/rat) reduced the uptake of labelled 5-HT into spinal synaptosomes by approximately 85% but did not significantly affect the uptake of noradrenaline. The lesions produced a significant hyperalgesia and strongly attenuated the analgesic effect of PCA in the hot-plate test. In the flinch-jump test 5,6-DHT lesioned rats receiving PCA did not differ from the saline control group. Spinal lesioning did not, however, affect one-way active avoidance performance and did not prevent the marked impairment of avoidance performance induced by PCA. Thus, the avoidance deficit caused by PCA is independent of the descending serotonergic pathways and of the analgesia induced by PCA. These results support the view of a differential involvement of the ascending and descending serotonergic projections in behavioural processes controlled by aversive stimuli.
在雄性大鼠中，研究了下行5-羟色胺（5-HT）通路的选择性损伤对5-HT释放化合物对氯苯丙胺（PCA，2.5毫克/千克）诱导的镇痛和回避缺陷的影响。鞘内注射5,6-二羟基色胺（20微克/只大鼠）使标记的5-HT进入脊髓突触体的摄取减少约85%，但对去甲肾上腺素的摄取没有显著影响。这些损伤在热板试验中产生了显著的痛觉过敏，并强烈减弱了PCA的镇痛作用。在退缩跳跃试验中，接受PCA的5,6-二羟基色胺损伤大鼠与生理盐水对照组没有差异。然而，脊髓损伤并不影响单向主动回避行为，也不能防止PCA诱导的回避行为的显著损伤。因此，PCA引起的回避缺陷与下行5-羟色胺能通路以及PCA诱导的镇痛无关。这些结果支持了在由厌恶刺激控制的行为过程中，上行和下行5-羟色胺能投射存在不同参与的观点。
