title: Pharmacological analysis of the variation in behavioural responses to tryptamine in five strains of mice.
abstract: The effects of tryptamine on behaviour were studied in five strains of mice. There were significant strain differences in the intensity of the 5-HT syndrome (head weaving and hindlimb abduction) and head twitch responses. The intensity of the 5-HT syndrome correlated significantly with the brain tryptamine content, although the occurrence of head twitch was unrelated. The 5-HT2 receptor antagonist, ketanserin, antagonized the head twitch responses elicited by tryptamine without affecting the head weaving or hindlimb abduction. Metergoline, an antagonist of both the 5-HT1 and 5-HT2 receptors, strongly inhibited both the 5-HT syndrome and the head twitch responses in all five strains. [3H]5-HT and [3H]ketanserin binding in the frontal cortex of the five strains of mice was also studied. The number of [3H]5-HT binding sites did not differ among the five strains of mice although there was a noticeable difference in the number of [3H]ketanserin binding sites. These results suggest that the 5-HT syndrome and the head twitch responses induced by tryptamine are linked separately with the 5-HT1 and 5-HT2 receptors, respectively. The strain differences in the tryptamine-induced 5-HT syndrome can be explained by the different levels of brain tryptamine. The differences in the head twitch responses in the mice are probably derived from the differences in the 5-HT2 receptor binding sites in the brain and the content of brain tryptamine.
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects; D007650:Ketanserin / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D008711:Metergoline / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D012701:Serotonin / Q000378:metabolism; D013045:Species Specificity; D014363:Tryptamines / Q000494:pharmacology*
chemical_list: D014363:Tryptamines; D008711:Metergoline; D012701:Serotonin; D007650:Ketanserin