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...
Abstract An intravenous dose of 20.0 mg/kg of mescaline induced a reproducible head‐twitch response in rats. Drugs with very different pharmacological activities were tested for potential inhibition of this response. Among these drugs were a large number of serotonin antagonists, including several members of the recently described selective S 2 antagonists of which ketanserin (a potent vascular...