Harvey J A
Department of Pharmacology, Medical College of Pennsylvania and Hahnemann University, Philadelphia 19129, USA.
Behav Brain Res. 1996;73(1-2):47-50. doi: 10.1016/0166-4328(96)00068-x.
This paper presents a review of studies dealing with the effects of 5-HT agonists and antagonists on learning as measured by classical conditioning of the rabbit's nictitating membrane response or the conditioned avoidance response in the rat. These studies indicate that the 5-HT2A/2C receptors are importantly involved in learning. In these behavioral paradigms, enhancement of learning is only produced by drugs that are agonists at the 5-HT2A/2C receptors, and this enhancement is only blocked by drugs that are antagonists at these receptors. In addition, evidence is presented for the existence of two classes of 5-HT2A/2C antagonists consisting of negative antagonists that retard learning when given alone (ritanserin, MDL-11,939, pizotifen and cyproheptadine) and those that are neutral antagonists in that they have no effect on learning (ketanserin, mianserin, BOL and LY-53,857). However, both the neutral and negative antagonists are equally capable of blocking the enhancement of learning produced by 5-HT2A/2C agonists. It was concluded that 5-HT2A and/or 5-HT2C agonists may provide a new approach to the treatment of learning disorders in aging or Alzheimer's disease.
本文综述了一系列研究，这些研究通过兔瞬膜反应的经典条件反射或大鼠的条件性回避反应来测量5-羟色胺（5-HT）激动剂和拮抗剂对学习的影响。这些研究表明，5-HT2A/2C受体在学习过程中起着重要作用。在这些行为范式中，只有5-HT2A/2C受体激动剂类药物才能增强学习，并且这种增强作用只能被这些受体的拮抗剂类药物所阻断。此外，有证据表明存在两类5-HT2A/2C拮抗剂：一类是负性拮抗剂，单独使用时会延缓学习（利坦色林、MDL-11,939、苯噻啶和赛庚啶）；另一类是中性拮抗剂，即对学习没有影响（酮色林、米安色林、BOL和LY-53,857）。然而，中性拮抗剂和负性拮抗剂都同样能够阻断5-HT2A/2C激动剂所产生的学习增强作用。得出的结论是，5-HT2A和/或5-HT2C激动剂可能为治疗衰老或阿尔茨海默病中的学习障碍提供一种新方法。
