title: Pargyline and tryptophan enhancement of tonic immobility: paradoxical attenuation with combined administration.
abstract: Four experiments were conducted to examine the individual and combined effects of pargyline and tryptophan on the duration of tonic immobility in chickens. Injection of either compound alone produced a dose-dependent potentiation of tonic immobility. However, combined administration of pargyline and tryptophan resulted in a dramatic attenuation of the response and this effect was completely blocked by pretreatment with p-chlorophenylalanine. In addition to reducing the duration of tonic immobility, combined administration of pargyline and tryptophan produced a complex behavioral syndrome which may be analogous to that observed in mammals after similar drug treatment. These results suggest the need for a modification of the recently proposed serotonergic-raphe model of tonic immobility.
mesh_terms: D000818:Animals; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D010134:Fenclonine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D010293:Pargyline / Q000494:pharmacology*; D012149:Restraint, Physical; D014364:Tryptophan / Q000494:pharmacology*
chemical_list: D014364:Tryptophan; D010293:Pargyline; D010134:Fenclonine