Factors triggering abolishment of benzodiazepines effects in the Four-Plate Test--retest in mice.
Abolishment of anxiolytic-like effects of diazepam occurs during re-exposure to some animal tests of anxiety. We investigated the loss of anxiolytic-like effects of diazepam during Trial 2 on previously undrugged mice, namely one-trial tolerance (OTT). Swiss mice were subjected to 1) Four-Plate Test (FPT) without punishments in Trial 1 or 2) FPT without punishments in both Trials or 3) FPT with spatial modifications in Trial 1 or 4) Elevated Plus Maze (EPM), then 24 h later to FPT, with saline, diazepam (1 mg/kg) or DOI (1 mg/kg). Removing punishments in Trial 1 does not counteract the effect reduction of diazepam in Trial 2, but spatial modifications of the aversive environment. Previous exposure to EPM does not trigger a loss of efficacy of diazepam in FPT. Electric punishments do not trigger OTT to benzodiazepines; whilst knowledge of the environment seems to be responsible for this phenomenon. FPT may be useful to study OTT because punishments potentate OTT in this model of anxiety.
Petit-Demoulière
B
B
EA 3256 Neurobiologie de l'anxiété et de la dépression, Faculté de Médecine, BP 53508, 1 Rue Gaston Veil, F44035 Nantes Cedex 01 France.
Hascoët
M
M
Bourin
M
M
D000662:Amphetamines / Q000494:pharmacology; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy* / Q000523:psychology; D001362:Avoidance Learning / Q000187:drug effects; D003975:Diazepam / Q000494:pharmacology*; D004361:Drug Tolerance; D004558:Electric Stimulation; D008297:Male; D051379:Mice; D011678:Punishment
D000662:Amphetamines; D014151:Anti-Anxiety Agents; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine; D003975:Diazepam