title: Head-twitches induced by p-hydroxyamphetamine in mice.
abstract: Head-twitches have been regarded as an experimental model of hallucination, and we have recently observed that p-hydroxyamphetamine (p-OHA) markedly induced head-twitches in mice. The present work was undertaken to study possible participation of a serotonergic system in the mechanism of head-twitches induced by p-OHA. Head-twitches induced by p-OHA continued for 20-80 min, and the peak time of this effect was approximately 30-40 min after the administration. The i.c.v. administration of p-OHA (20, 40, 80 and 160 micrograms/mouse) produced characteristic head-twitches in a dose-dependent manner. Simultaneous injection of serotonin (10 micrograms/mouse, i.c.v.) and p-OHA caused a 2-2.5-fold increase in the number of head-twitches compared with non-serotonin controls. Pretreatment with p-chlorophenylalanine (200 mg/kg, i.p. and 500 micrograms/mouse, i.c.v.), in contrast, reduced head-twitches as did the pretreatment with cyproheptadine or dimethothiazine. These results suggest that p-OHA-induced head-twitches may involve the central serotonergic system which may exert an excitatory effect on head-twitches.
mesh_terms: D000662:Amphetamines / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000503:physiopathology; D004195:Disease Models, Animal; D006212:Hallucinations / Q000139:chemically induced* / Q000503:physiopathology; D006213:Hallucinogens; D006257:Head; D008297:Male; D051379:Mice; D009069:Movement Disorders / Q000139:chemically induced* / Q000503:physiopathology; D009435:Synaptic Transmission; D010136:p-Hydroxyamphetamine / Q000494:pharmacology*
chemical_list: D000662:Amphetamines; D006213:Hallucinogens; D010136:p-Hydroxyamphetamine