Colpaert F C, Meert T F, Niemegeers C J, Janssen P A
Psychopharmacology (Berl). 1985;86(1-2):45-54. doi: 10.1007/BF00431683.
The newly synthesized compound and putative 5-HT2 antagonist ritanserin, but not the structurally related compound R 56413, resembles pirenperone in that it acts as a pure antagonist in an LSD-saline drug discrimination assay in the rat. Ritanserin exceeded pirenperone in terms of behavioral specificity; the lowest effective dose of ritanserin in antagonizing LSD was one order of magnitude higher than that of pirenperone, but the compound depressed rate of operant responding only at doses that were about 1000-fold higher than those at which pirenperone was effective. Ritanserin exerted effects in an open field test which were reminiscent of anxiolytic drug activity in the rat; its effects were greater than those of pirenperone, R 56413 and the benzodiazepines chlordiazepoxide and diazepam. The results of experiments on antagonism of 5-HT-induced hypothermia and of the 5-HTP-induced head-twitch response fail to support the possibility that the putative anxiolytic effects of ritanserin in the rat can be ascribed simply to a pharmacologically defined action at 5-HT receptors.
新合成的化合物以及假定的5-羟色胺2（5-HT2）拮抗剂利坦色林，而非结构相关化合物R 56413，在大鼠的麦角酸二乙酰胺（LSD）-生理盐水药物辨别试验中表现为纯拮抗剂，这一点与匹仑哌隆相似。利坦色林在行为特异性方面超过了匹仑哌隆；利坦色林拮抗LSD的最低有效剂量比匹仑哌隆高一个数量级，但该化合物仅在比匹仑哌隆有效剂量高约1000倍的剂量下才会抑制操作性反应速率。利坦色林在旷场试验中产生的效应使人联想到大鼠体内抗焦虑药物的活性；其效应大于匹仑哌隆、R 56413以及苯二氮䓬类药物氯氮卓和地西泮。关于拮抗5-羟色胺（5-HT）诱导的体温过低以及5-羟色氨酸（5-HTP）诱导的头部抽搐反应的实验结果，无法支持利坦色林在大鼠体内假定的抗焦虑效应可简单归因于其对5-HT受体的药理学定义作用这一可能性。
