We distinguished the functions of the different 5-hydroxytryptamine-2 (5-HT(2)) receptor (5-HT(2)R) subtypes in the tryptamine-induced 5-HT syndrome in rats using (1) the 5-HT(2A)R antagonist R93274 (N-[(3-p-fluorophenyl-1-propyl)-4-methyl-4-piperidinyl]-4-amino-5-iodo-2-methoxybenzamide), the 5-HT(2A/C)R antagonist R99647...
Abstract Ritanserin, a novel methylenepiperidine derivative, was studied in a wide range of common pharmacological tests mainly in rats. The lowest ED 50 , 0.0070 mg/kg, was obtained against tryptamine‐induced cyanosis. At 0.037 mg/kg, tryptamine‐induced bilateral clonic seizures were inhibited. Slightly higher doses, up to 0.11 mg/kg, inhibited mescaline and 5‐hydroxytryptophan (5‐HTP)‐induced...
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...