Effects of buspirone on antinociceptive and behaviourial responses to the elevated plus-maze in mice

Brief exposure to an elevated plus-maze (EPM) induces antinociception in male mice, a reaction that is not blocked by opiate receptor manipulations but which is completely inhibited by the benzodiazepine receptor agonist, diazepam. The present study examined the effects of a non-benzodiazepine anxiolytic, buspirone, on EPM antinociception and behaviour. EPM antinociception was completely abolished by 10mg/kg buspirone but was largely unaffected by lower doses (0.1-1.0mg/kg) of the compound. Behaviourally, 1-10mg/kg buspirone produced changes indicative of anxiety reduction, although the high dose anxiolytic profile was at least partially compromised by a general reduction in behaviour. Data are discussed in relation to the proposal that anxiety may be a critical factor in non-opioid forms of adaptive pain inhibition.