The regulation of the 5-HT2 receptor-mediated head twitch response and of 5-HT2 receptor binding in the frontal cortex was studied in rats treated repeatedly with the 5-HT2 agonist 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) (2.5 mg/kg, s.c.). Four injections in 24 h produced a near maximal reduction in the behaviour (-70%) and in the Bmax for [3H]ketanserin binding (-41%). The KD...
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...
Using a food-reinforced two-lever operant method, rats (n = 9) were trained to discriminate 0.16 mg/kg LSD from saline. Tests for stimulus generalization in rats so trained indicated that the purported 5-HT antagonists cyproheptadine (1.25 and 10 mg/kg), methysergide (0.16 to 10 mg/kg) and mianserin (2.5 to 40 mg/kg) produced partial generalization with LSD. The hallucinogens mescaline (5 to 40...