Production of climbing behaviour in mice requires both D1 and D2 receptor activation

The ability of SKF38393 (a D1 agonist), quinpirole (a D2 agonist), and apomorphine (a mixed D1/D2 agonist) to induce stereotyped climbing behaviour in mice was investigated. Apomorphine produced a dose-related increase in stereotyped cage climbing which lasted for up to 60 min. SKF38393 and quinpirole failed to produce climbing when administered alone. When given in combination intense apomorphine-like cage climbing was observed which lasted for up to 2 h. Apomorphine or the combination of SKF38393 and quinpirole also produced biting of the cage. The climbing behaviour produced by either apomorphine or SKF38393/quinpirole combinations was antagonised by either the D1 antagonist, SCH23390 or the D2 antagonist clebopride. These results demonstrate that both D1 and D2 receptor activation is necessary to produce apomorphine-like cage climbing in mice.