ABSTRACT
Within groups of rats rank–specific behavioural patterns have been discerned by either recording offensive and defensive postures and/or observing each individual’s performance for a rewarding stimulus of limited availability (e.g. food or fluid or a sexual partner). Having recently described a stable intragroup rank–order when assessing each individual’s tendency to partake in competition for sucrose–pellets (Gentsch, Lichtsteiner & Feer, 1988), we asked whether the competition–rate of so–called high– or poor–performing rats could be affected by pharmacological interventions. Among others, serotonergic drugs influence the competition–rates for sucrose–pellets as follows: by inhibiting 5–HT–synthesis in poor–performing rats these animals temporarily overcome their characteristic abstention from competition and, after administration of quipazine, a 5–HT–agonist, the high–performing rats’ competition–rate is temporarily attenuated (Gentsch et al., unpublished). Such findings which are corroborating previous observations (Kostowski, Plewako & Bidzingski, 1984), indicate that the competition–rate might be related to the activity of the 5–HT–system.
