title: A behavioural and pharmacological evaluation of the discriminative stimulus induced by pentylenetetrazole in the pig.
abstract: The anxiogenic nature of the interoceptive discriminative stimulus induced by pentylenetetrazole (PTZ) was investigated by examining the discriminatory behaviour of PTZ conditioned pigs during a conditioned emotional response (CER). A CER was induced in a nonoperant situation, by pairing a tone stimulus with the application of a mild, non-injurious electric shock. Subsequent presentation of the conditioned tone stimulus alone produced a generalisation to the PTZ cue. This generalisation of the conditioned emotional state (CES) to the PTZ cue was antagonised by pretreatment with diazepam (0.5 mg/kg, PO; 30 min). The PTZ stimulus was also antagonised by diazepam (0.5 mg/kg, PO; 30 min) but not by an anticonvulsant dose of ethosuximide (30 mg/kg, PO; 1-3 h), providing further confirmation of the anxiogenic nature of the PTZ cue. Our results demonstrate the validity of the PTZ discrimination paradigm in pigs as a test of anxiety.
authors.affiliation: Department of Physiology, University College London, UK.
authors.forename: M P
authors.initials: MP
authors.lastname: Carey
authors.forename: J P
authors.initials: JP
authors.lastname: Fry
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects; D003463:Cues; D003975:Diazepam / Q000494:pharmacology; D004192:Discrimination, Psychological / Q000187:drug effects*; D004597:Electroshock; D004644:Emotions / Q000187:drug effects; D005013:Ethosuximide / Q000494:pharmacology; D008297:Male; D010433:Pentylenetetrazole / Q000494:pharmacology*; D012055:Reinforcement Schedule; D013552:Swine
chemical_list: D005013:Ethosuximide; D003975:Diazepam; D010433:Pentylenetetrazole