Drug
SB242084 (6-chloro-5-methyl-1-[2(2methylpyridyl- 3-oxy)-pyrid-5-yl carbamoyl] indoline hydrochloride; Tocris, Bristol, UK) was initially dissolved in PEG400 (Sigma-Aldrich, Poole, UK) at 20% of the final required volume, which was then made up by 10% (w/v) hydroxypropyl-beta-cyclodextrin (Fluka, Poole, UK). The stock solution was aliquoted and frozen at −80°C in vials of quantities required for each test day. Each animal in Experiment 1 was dosed at 0.5 mg/kg subcutaneously (s.c.) in the nape of the neck at a volume of 4 ml/kg 30 min prior to behavioural testing.