title: Acute and chronic effects of the triazolobenzo-diazepine, alprazolam, on defeat and analgesia evoked by conspecific attack in male mice.
abstract: Behavioural and pharmacological evidence suggest that non-opioid analgesia in defeated male mice is a consequence of anxiety provoked by ecologically relevant aspects of the stimulus situation. The effects of acute and chronic alprazolam (0.05-2.0mg/kg, i.p.) treatment on basal nociception, defeat behaviour and analgesia evoked by conspecific attack are assessed. Results show that basal nociception (tail-flick assay) was unaffected by acute or chronic drug treatment, and that attack-induced analgesia was unaltered by acute administration of 0.05-0.50mg/kg alprazolam. Higher acute doses (1-2mg/kg) of the compound inhibited locomotor activity, markedly interfered with the display of defeat postures and resulted in the exposure of intruders to higher than normal levels of attack. Though 1mg/kg alprazolam (acute) significantly inhibited the analgesic consequences of conspecific attack, this effect went at a higher dose. Chronic drug administration led to the development of tolerance to the inhibitory effects of higher alprazolam doses on locomotor activity and, over the dose range 0.5-2mg/kg, to the complete inhibition of analgesic consequences of conspecific attack. Nonetheless, mice treated chronically with 0.5-2mg/kg still failed to display defeat within the maximum time allotted for encounters, suggesting that this behavioural effect may be a valid index of anxiolytic activity. Data are discussed in relation to the possible involvement of panic in intruder analgesia.
authors.affiliation: Pharmacoethology Laboratory, Department of Psychology, University of Bradford, UK Correspondence: Department of Psychology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: J.K.
authors.initials: JK
authors.lastname: Shepherd
authors.forename: R.J.
authors.initials: RJ
authors.lastname: Rodgers