Institute of Pharmacology and Pharmacognosy, School of Pharmacy, University of Turin, Italy.
1. The effects of a chronic administration (around 30 mg/ kg/day) of the dihydropyridine calcium antagonist nimodipine, on apomorphine induced yawning behaviour of grouped or individual housed rats, were studied. 2. Nimodipine treatment had no effect in grouped rats. 3. Individually housed animals gave a significant lower number of yawns in respect to grouped controls: this difference disappeared in isolated, nimodipine treated, group. 4. The results show the ability of nimodipine to restore a depressed behavioural performance.